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  3. Slim Node Si7021 sensor example

Slim Node Si7021 sensor example

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  • carlierdC Offline
    carlierdC Offline
    carlierd
    wrote on last edited by
    #8

    @m26872 : I don't use booster. You think it's necessary ? 90uA is really important for battery operation.

    For the design off course I will make it open hardware :)

    David.

    m26872M A 2 Replies Last reply
    0
    • carlierdC carlierd

      @m26872 : I don't use booster. You think it's necessary ? 90uA is really important for battery operation.

      For the design off course I will make it open hardware :)

      David.

      m26872M Offline
      m26872M Offline
      m26872
      Hardware Contributor
      wrote on last edited by
      #9

      @carlierd What's your setup then? The DHT22 is for 3.3-5.5V.

      carlierdC 1 Reply Last reply
      0
      • A Offline
        A Offline
        ar91
        wrote on last edited by ar91
        #10

        @m26872 I have built the Slim Node described above and i am using your exact sketch given above but when i look at the serial monitor, it is printing junk characters i tried different baud rates on the serial monitor but nothing works.

        I am connected to the slim node using FTDI board.

        Any thoughts?

        Thanks for your help.

        m26872M 1 Reply Last reply
        0
        • A ar91

          @m26872 I have built the Slim Node described above and i am using your exact sketch given above but when i look at the serial monitor, it is printing junk characters i tried different baud rates on the serial monitor but nothing works.

          I am connected to the slim node using FTDI board.

          Any thoughts?

          Thanks for your help.

          m26872M Offline
          m26872M Offline
          m26872
          Hardware Contributor
          wrote on last edited by
          #11

          @ar91 Did you change baud rate in MySensors config too?

          A 1 Reply Last reply
          0
          • m26872M m26872

            I've tried to post some sensor examples in the main Slim Node thread. It's continuously growing and I think it's better to start new threads for as much as possible. Here's one. I used this Si7021 (GY-21 board).

            0_1454701237885_20160205_115230_bottom.jpg
            0_1454701249276_20160205_115440_top.jpg
            0_1454701293649_20160205_115016_caps.jpg

            Sketch
            Apologize for still not having cleaned up the sketch yet ...

            /* Sketch with Si7021 and battery monitoring.
            by m26872, 20151109 
            */
            #include <MySensor.h>  
            #include <Wire.h>
            #include <SI7021.h>
            #include <SPI.h>
            #include <RunningAverage.h>
            
            //#define DEBUG
            
            #ifdef DEBUG
            #define DEBUG_SERIAL(x) Serial.begin(x)
            #define DEBUG_PRINT(x) Serial.print(x)
            #define DEBUG_PRINTLN(x) Serial.println(x)
            #else
            #define DEBUG_SERIAL(x)
            #define DEBUG_PRINT(x) 
            #define DEBUG_PRINTLN(x) 
            #endif
            
            #define NODE_ID 132             // <<<<<<<<<<<<<<<<<<<<<<<<<<<   Enter Node_ID
            #define CHILD_ID_TEMP 0
            #define CHILD_ID_HUM 1
            // #define SLEEP_TIME 15000 // 15s for DEBUG
            #define SLEEP_TIME 300000   // 5 min
            #define FORCE_TRANSMIT_CYCLE 36  // 5min*12=1/hour, 5min*36=1/3hour 
            #define BATTERY_REPORT_CYCLE 2880   // Once per 5min   =>   12*24*7 = 2016 (one report/week)
            #define VMIN 1900
            #define VMAX 3300
            #define HUMI_TRANSMIT_THRESHOLD 3.0  // THRESHOLD tells how much the value should have changed since last time it was transmitted.
            #define TEMP_TRANSMIT_THRESHOLD 0.5
            #define AVERAGES 2
            
            int batteryReportCounter = BATTERY_REPORT_CYCLE - 1;  // to make it report the first time.
            int measureCount = 0;
            float lastTemperature = -100;
            int lastHumidity = -100;
            
            RunningAverage raHum(AVERAGES);
            SI7021 humiditySensor;
            
            MySensor gw;
            MyMessage msgTemp(CHILD_ID_TEMP,V_TEMP); // Initialize temperature message
            MyMessage msgHum(CHILD_ID_HUM,V_HUM);
            
            void setup() {
              DEBUG_SERIAL(115200);    // <<<<<<<<<<<<<<<<<<<<<<<<<< Note BAUD_RATE in MySensors.h
              DEBUG_PRINTLN("Serial started");
              
              DEBUG_PRINT("Voltage: ");
              DEBUG_PRINT(readVcc()); 
              DEBUG_PRINTLN(" mV");
            /*
              delay(500);
              DEBUG_PRINT("Internal temp: ");
              DEBUG_PRINT(GetInternalTemp()); // Probably not calibrated. Just to print something.
              DEBUG_PRINTLN(" *C");
            */  
              delay(500); // Allow time for radio if power useed as reset
              gw.begin(NULL,NODE_ID);
              gw.sendSketchInfo("EgTmpHumBat5min", "1.0 151106"); 
              gw.present(CHILD_ID_TEMP, S_TEMP);   // Present sensor to controller
              gw.present(CHILD_ID_HUM, S_HUM);
              DEBUG_PRINT("Node and "); DEBUG_PRINTLN("2 children presented.");
              
              raHum.clear();
              
            }
            
            void loop() { 
            
              measureCount ++;
              batteryReportCounter ++;
              bool forceTransmit = false;
              
              if (measureCount > FORCE_TRANSMIT_CYCLE) {
            	forceTransmit = true; 
              }
              sendTempHumidityMeasurements(forceTransmit);
            /*
              // Read and print internal temp
              float temperature0 = static_cast<float>(static_cast<int>((GetInternalTemp()+0.5) * 10.)) / 10.;
              DEBUG_PRINT("Internal Temp: "); DEBUG_PRINT(temperature0); DEBUG_PRINTLN(" *C");        
            */
              // Check battery
              if (batteryReportCounter >= BATTERY_REPORT_CYCLE) {
            	long batteryVolt = readVcc();
            	DEBUG_PRINT("Battery voltage: "); DEBUG_PRINT(batteryVolt); DEBUG_PRINTLN(" mV");
            	uint8_t batteryPcnt = constrain(map(batteryVolt,VMIN,VMAX,0,100),0,255);   
            	DEBUG_PRINT("Battery percent: "); DEBUG_PRINT(batteryPcnt); DEBUG_PRINTLN(" %");
            	gw.sendBatteryLevel(batteryPcnt);
            	batteryReportCounter = 0;
              }
              
              gw.sleep(SLEEP_TIME);
            }
            
            // function for reading Vcc by reading 1.1V reference against AVcc. Based from http://provideyourown.com/2012/secret-arduino-voltmeter-measure-battery-voltage/
            // To calibrate reading replace 1125300L with scale_constant = internal1.1Ref * 1023 * 1000, where internal1.1Ref = 1.1 * Vcc1 (per voltmeter) / Vcc2 (per readVcc() function) 
            long readVcc() {
              // set the reference to Vcc and the measurement to the internal 1.1V reference
              ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
              delay(2); // Wait for Vref to settle
              ADCSRA |= _BV(ADSC); // Start conversion
              while (bit_is_set(ADCSRA,ADSC)); // measuring
              uint8_t low  = ADCL; // must read ADCL first - it then locks ADCH  
              uint8_t high = ADCH; // unlocks both
              long result = (high<<8) | low;
              result = 1125300L / result; // Calculate Vcc (in mV); 1125300 = 1.1*1023*1000
              return result; // Vcc in millivolts
            }
            // function for reading internal temp. From http://playground.arduino.cc/Main/InternalTemperatureSensor 
            double GetInternalTemp(void) {  // (Both double and float are 4 byte in most arduino implementation)
              unsigned int wADC;
              double t;
              // The internal temperature has to be used with the internal reference of 1.1V. Channel 8 can not be selected with the analogRead function yet.
              ADMUX = (_BV(REFS1) | _BV(REFS0) | _BV(MUX3));   // Set the internal reference and mux.
              ADCSRA |= _BV(ADEN);  // enable the ADC
              delay(20);            // wait for voltages to become stable.
              ADCSRA |= _BV(ADSC);  // Start the ADC
              while (bit_is_set(ADCSRA,ADSC));   // Detect end-of-conversion
              wADC = ADCW;   // Reading register "ADCW" takes care of how to read ADCL and ADCH.
              t = (wADC - 88.0 ) / 1.0;   // The default offset is 324.31.
              return (t);   // The returned temperature in degrees Celcius.
            }
            
            /*********************************************
             * * Sends temperature and humidity from Si7021 sensor
             * Parameters
             * - force : Forces transmission of a value (even if it's the same as previous measurement)
             *********************************************/
            void sendTempHumidityMeasurements(bool force) {
              bool tx = force;
            
              si7021_env data = humiditySensor.getHumidityAndTemperature();
              
              float temperature = data.celsiusHundredths / 100.0;
              DEBUG_PRINT("T: ");DEBUG_PRINTLN(temperature);
              float diffTemp = abs(lastTemperature - temperature);
              DEBUG_PRINT(F("TempDiff :"));DEBUG_PRINTLN(diffTemp);
              if (diffTemp > TEMP_TRANSMIT_THRESHOLD || tx) {
            	gw.send(msgTemp.set(temperature,1));
            	lastTemperature = temperature;
            	measureCount = 0;
            	DEBUG_PRINTLN("T sent!");
              }
              
              int humidity = data.humidityPercent;
              DEBUG_PRINT("H: ");DEBUG_PRINTLN(humidity);
              raHum.addValue(humidity);
              humidity = raHum.getAverage();  // MA sample imply reasonable fast sample frequency
              float diffHum = abs(lastHumidity - humidity);  
              DEBUG_PRINT(F("HumDiff  :"));DEBUG_PRINTLN(diffHum); 
              if (diffHum > HUMI_TRANSMIT_THRESHOLD || tx) {
            	gw.send(msgHum.set(humidity));
            	lastHumidity = humidity;
            	measureCount = 0;
            	DEBUG_PRINTLN("H sent!");
              }
            
            }
            

            Notes
            Here (and often in other projects as well) the GY-21 board is used to provide the Si7021 sensor . I'm not sure about the identity of components on it, but apart from the sensor the board also includes a small 3.3V-regulator (LDO), mosfets for logic level convertion, supporting capacitors and pull-up resistors.

            The voltage regulator is desoldered and bypassed in pictures above. This gained a node sleep current reduction from 10.7uA to ~6uA. This is the only modification necessary to do on the GY-21.

            The GY-21 board is obviously designed for 5V-projects, but removing-/bypassing the v-reg is enough for using it in our low power 3.3-1.9V applications. @riataman was the first to show the mod of the GY-21 board in this post. There's also a link to a board without the v-reg and level converter. If you design you own pcb you'll probably use the Si7021 bare chip instead of the GY-21 board.

            I had some thoughts about voltage dropout level and the level converter. In the end I still have thoughts, but my experiments show no issues. Here's a description of the level converter working principle. Remember that I don't know if these specs are equivalent, but looking at the mosfet datasheet, it says "Diode forward voltage drop 0.85-1.5V" and "Gate threshold voltage 1.0-2.5V". It's also an "Enhancment mode" FET, where the threshold voltage is important according to this. All together makes me worried about the High side capability to pull down Low side when High side volt is <2V instead of 5V. My tests show differently though. There are no real issues with this. The Si7021 worked down to ~1.7-1.8V with no significant difference whether the level converter was bypassed or not. Comparing one node with bypassed level converter to one without, showed ~1uA lower sleep mode current. But I assume it could just as well be a matter of the individual variations. If anyone like to bypass their level converter, here's a picture.

            0_1454768184528_20160201_205055_convbypass.jpg

            GertSandersG Offline
            GertSandersG Offline
            GertSanders
            Hardware Contributor
            wrote on last edited by
            #12

            @m26872 There is another version of the SI7021 board without voltage regulator. This evening I will look up the link on Aliexpress. The boards are smaller then the GY-21 variant.

            1 Reply Last reply
            0
            • m26872M m26872

              @ar91 Did you change baud rate in MySensors config too?

              A Offline
              A Offline
              ar91
              wrote on last edited by
              #13

              Thanks @m26872, I changed the baud rate on MyConfig.h and it started working.

              1 Reply Last reply
              1
              • m26872M m26872

                @carlierd What's your setup then? The DHT22 is for 3.3-5.5V.

                carlierdC Offline
                carlierdC Offline
                carlierd
                wrote on last edited by
                #14

                @m26872 My nodes are working correctly for the moment. Actually one is at 2.8v. Perhaps I will have problem when voltage will be lower !

                David.

                m26872M 1 Reply Last reply
                0
                • carlierdC carlierd

                  @m26872 My nodes are working correctly for the moment. Actually one is at 2.8v. Perhaps I will have problem when voltage will be lower !

                  David.

                  m26872M Offline
                  m26872M Offline
                  m26872
                  Hardware Contributor
                  wrote on last edited by
                  #15

                  @carlierd Probably. That's why I ask what you use. DHT22 connected straight to 2AA will not utilize battery capacity. Higher battery voltage with step down regulator would be better - or maybe without, but with like 3AAs or so.

                  carlierdC 1 Reply Last reply
                  0
                  • carlierdC carlierd

                    @m26872 : I don't use booster. You think it's necessary ? 90uA is really important for battery operation.

                    For the design off course I will make it open hardware :)

                    David.

                    A Offline
                    A Offline
                    ar91
                    wrote on last edited by
                    #16

                    @carlierd With Slim Node running at 1Mhz even with or without booster i am having hardtime making DHT22 work. I even tried different libraries but none of them works at 1Mhz. How did you get it work?

                    m26872M carlierdC 2 Replies Last reply
                    0
                    • A ar91

                      @carlierd With Slim Node running at 1Mhz even with or without booster i am having hardtime making DHT22 work. I even tried different libraries but none of them works at 1Mhz. How did you get it work?

                      m26872M Offline
                      m26872M Offline
                      m26872
                      Hardware Contributor
                      wrote on last edited by
                      #17

                      @ar91 I don't think there's a good reason to go below 8MHz if DHT22 doesn't work much below 3.3V ?

                      1 Reply Last reply
                      1
                      • m26872M m26872

                        @carlierd Probably. That's why I ask what you use. DHT22 connected straight to 2AA will not utilize battery capacity. Higher battery voltage with step down regulator would be better - or maybe without, but with like 3AAs or so.

                        carlierdC Offline
                        carlierdC Offline
                        carlierd
                        wrote on last edited by
                        #18

                        @m26872 Perhaps that with a caps I can go very low. I want to have at least one year on 2 AA. Wait and see !

                        1 Reply Last reply
                        0
                        • A ar91

                          @carlierd With Slim Node running at 1Mhz even with or without booster i am having hardtime making DHT22 work. I even tried different libraries but none of them works at 1Mhz. How did you get it work?

                          carlierdC Offline
                          carlierdC Offline
                          carlierd
                          wrote on last edited by
                          #19

                          @ar91 Hello. I am using the arduino playground lib. No issue with it ! I can post a sketch if necessary.

                          David.

                          A 1 Reply Last reply
                          0
                          • carlierdC carlierd

                            @ar91 Hello. I am using the arduino playground lib. No issue with it ! I can post a sketch if necessary.

                            David.

                            A Offline
                            A Offline
                            ar91
                            wrote on last edited by
                            #20

                            @carlierd If you could share your code that will be great.

                            carlierdC 1 Reply Last reply
                            0
                            • A ar91

                              @carlierd If you could share your code that will be great.

                              carlierdC Offline
                              carlierdC Offline
                              carlierd
                              wrote on last edited by
                              #21

                              @ar91 Please find the code I used in 3 different nodes. The good thing with the playground lib is that there is error message if dialog with DHT22 failed.

                              /**
                               * The MySensors Arduino library handles the wireless radio link and protocol
                               * between your home built sensors/actuators and HA controller of choice.
                               * The sensors forms a self healing radio network with optional repeaters. Each
                               * repeater and gateway builds a routing tables in EEPROM which keeps track of the
                               * network topology allowing messages to be routed to nodes.
                               *
                               * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
                               * Copyright (C) 2013-2015 Sensnology AB
                               * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
                               *
                               * Documentation: http://www.mysensors.org
                               * Support Forum: http://forum.mysensors.org
                               *
                               * This program is free software; you can redistribute it and/or
                               * modify it under the terms of the GNU General Public License
                               * version 2 as published by the Free Software Foundation.
                               *
                               */
                              
                              /**************************************************************************************/
                              /* Temperature, humidity and luminosity measurements.                                 */
                              /*                                                                                    */
                              /* Version     : 1.1.6                                                                */
                              /* Date        : 10/01/2016                                                           */
                              /* Modified by : David Carlier                                                        */
                              /**************************************************************************************/
                              /*                                ---------------                                     */
                              /*                            RST |             |  A5                                 */
                              /*                            RX  |             |  A4                                 */
                              /*                            TX  |   ARDUINO   |  A3                                 */
                              /*     RFM69 (DIO0) --------- D2  |     UNO     |  A2                                 */
                              /*            DHT22 --------- D3  |             |  A1                                 */
                              /*            Power --------- D4  | ATMEGA 328p |  A0 --------- Light dep. resistor   */
                              /*              +3v --------- VCC |             | GND --------- GND                   */
                              /*              GND --------- GND |  8MHz int.  | REF                                 */
                              /*                            OSC |             | VCC --------- +3v                   */
                              /*                            OSC |             | D13 --------- RFM69 (SCK)           */
                              /*                            D5  |             | D12 --------- RFM69 (MISO)          */
                              /*                            D6  |             | D11 --------- RFM69 (MOSI)          */
                              /*                            D7  |             | D10 --------- RFM69 (NSS)           */
                              /*                            D8  |             |  D9                                 */
                              /*                                ---------------                                     */
                              /*                                                                                    */
                              /* Power = Vcc for LDR.                                                               */
                              /* +3v = 2*AA                                                                         */
                              /*                                                                                    */
                              /**************************************************************************************/
                              
                              #include <SPI.h>
                              #include <MySensor.h>
                              #include <dht.h>
                              #include <MyTransportRFM69.h>
                              #include <MySigningAtsha204Soft.h>
                              
                              #define CHILD_ID_HUM 0
                              #define CHILD_ID_TEMP 1
                              #define CHILD_ID_LIGHT 2
                              #define CHILD_ID_VOLTAGE 3
                              #define LIGHT_SENSOR_ANALOG_PIN 0
                              #define HUMIDITY_SENSOR_DIGITAL_PIN 3
                              #define POWER_PIN 4
                              //unsigned long SLEEP_TIME = 850000; // Sleep time between reads (in milliseconds) (close to 15')
                              unsigned long SLEEP_TIME = 275000; // Sleep time between reads (in milliseconds) (close to 5')
                              
                              //Construct MySensors library
                              MySigningAtsha204Soft signer;
                              MyHwATMega328 hw;
                              MyTransportRFM69 transport;
                              MySensor gw(transport, hw, signer);
                              dht DHT;
                              MyMessage msgHum(CHILD_ID_HUM, V_HUM);
                              MyMessage msgTemp(CHILD_ID_TEMP, V_TEMP);
                              MyMessage msgLum(CHILD_ID_LIGHT, V_LEVEL);
                              MyMessage msgVolt(CHILD_ID_VOLTAGE, V_VOLTAGE);
                              
                              /**************************************************************************************/
                              /* Initialization                                                                     */
                              /**************************************************************************************/
                              void setup()
                                {
                                //Get time (for setup duration)
                                #ifdef DEBUG
                                  unsigned long startTime = millis();
                                #endif
                              
                                //Start MySensors
                                gw.begin();
                              
                                //Send the Sketch Version Information to the Gateway
                                gw.sendSketchInfo("GHAS sensor", "1.1.5");
                              
                                //Register all sensors to gw (they will be created as child devices)
                                gw.present(CHILD_ID_HUM, S_HUM);
                                gw.present(CHILD_ID_TEMP, S_TEMP);
                                gw.present(CHILD_ID_LIGHT, S_LIGHT_LEVEL);
                                gw.present(CHILD_ID_VOLTAGE, S_MULTIMETER);
                              
                                //Delay for DHT22
                                delay(1500);
                              
                                //Print setup debug
                                #ifdef DEBUG
                                  int duration = millis() - startTime;
                                  Serial.print("[Setup duration: "); Serial.print(duration, DEC); Serial.println(" ms]");
                                #endif
                                }
                              
                              /**************************************************************************************/
                              /* Main loop                                                                          */
                              /**************************************************************************************/
                              void loop()
                                {
                                //Get time (for a complete loop)
                                #ifdef DEBUG
                                  unsigned long startTime = millis();
                                #endif
                              
                                //Power on
                                powerOnPeripherals();
                              
                                //Get DHT22 data
                                int dht22Result = DHT.read22(HUMIDITY_SENSOR_DIGITAL_PIN);
                                switch (dht22Result)
                                  {
                                  case DHTLIB_OK:  
                                              //Serial.println("OK,\t");
                                              break;
                                  case DHTLIB_ERROR_CHECKSUM:
                                              #ifdef DEBUG
                                                Serial.println("Checksum error,\t");
                                              #endif
                                              break;
                                  case DHTLIB_ERROR_TIMEOUT:
                                              #ifdef DEBUG
                                                Serial.println("Time out error,\t");
                                              #endif
                                              break;
                                  case DHTLIB_ERROR_CONNECT:
                                              #ifdef DEBUG
                                                Serial.println("Connect error,\t");
                                              #endif
                                              break;
                                  case DHTLIB_ERROR_ACK_L:
                                              #ifdef DEBUG
                                                Serial.println("Ack Low error,\t");
                                              #endif
                                              break;
                                  case DHTLIB_ERROR_ACK_H:
                                              #ifdef DEBUG
                                                Serial.println("Ack High error,\t");
                                              #endif
                                              break;
                                  default:
                                              #ifdef DEBUG
                                                Serial.println("Unknown error,\t");
                                              #endif
                                              break;
                                  }
                              
                                //Get temperature and humidity
                                float temperature = 0;
                                float humidity = 0;
                                if (dht22Result == DHTLIB_OK)
                                  {
                                  temperature = DHT.temperature;
                                  humidity = DHT.humidity;
                                  }
                              
                                //Get power before luminosity to use real voltage
                                float realVoltage = getVoltage() / 100.0;
                                int batteryPcnt = realVoltage * 100 / 3.0;
                                if (batteryPcnt > 100) {batteryPcnt = 100;}
                                int lux = computeIlluminance(realVoltage);
                              
                                //Power off
                                powerOffPeripherals();
                              
                                //Send data to gateway
                                gw.send(msgHum.set(humidity, 1));
                                gw.send(msgTemp.set(temperature, 1));
                                gw.send(msgLum.set(lux));
                                gw.send(msgVolt.set(realVoltage, 2));
                                gw.sendBatteryLevel(batteryPcnt);
                              
                                //Print debug
                                #ifdef DEBUG
                                  Serial.print(temperature, 1);
                                  Serial.print(" degC");
                                  Serial.print("   ");
                                  Serial.print(humidity, 1);
                                  Serial.print(" %");
                                  Serial.print("   ");
                                  Serial.print(lux);
                                  Serial.print(" lx");
                                  Serial.print("   ");
                                  Serial.print(realVoltage);
                                  Serial.print(" v");
                                  int duration = millis() - startTime;
                                  Serial.print("   ");
                                  Serial.print("["); Serial.print(duration, DEC); Serial.println(" ms]");
                                  Serial.flush();
                                #endif
                              
                                //Sleep
                                gw.sleep(SLEEP_TIME);
                                }
                              
                              /**************************************************************************************/
                              /* Allows to compute illuminance (in LUX) from LIGHT_SENSOR_ANALOG_PIN.               */
                              /**************************************************************************************/
                              int computeIlluminance(float realVoltage)
                                {
                                //Get luminosity
                                int luminosity = analogRead(LIGHT_SENSOR_ANALOG_PIN);
                                //Calculating the voltage in the input of the ADC
                                double voltage = realVoltage * ((double)luminosity / 1024.0);
                                //Calculating the resistance of the photoresistor in the voltage divider
                                double resistance = (10.0 * realVoltage) / voltage - 10.0;
                                //Calculating the intensity of light in lux and return it
                                int illuminance = 255.84 * pow(resistance, -10/9);
                                return illuminance;
                                }
                              
                              /**************************************************************************************/
                              /* Allows to get the real Vcc (return value * 100).                                   */
                              /**************************************************************************************/
                              int getVoltage()
                                {
                                const long InternalReferenceVoltage = 1056L;
                                ADMUX = (0<<REFS1) | (1<<REFS0) | (0<<ADLAR) | (1<<MUX3) | (1<<MUX2) | (1<<MUX1) | (0<<MUX0);
                                delay(50);  // Let mux settle a little to get a more stable A/D conversion
                                //Start a conversion  
                                ADCSRA |= _BV( ADSC );
                                //Wait for it to complete
                                while (((ADCSRA & (1<<ADSC)) != 0));
                                //Scale the value
                                int result = (((InternalReferenceVoltage * 1023L) / ADC) + 5L) / 10L;
                                return result;
                                }
                              
                              /**************************************************************************************/
                              /* Allows to power ON peripherals.                                                    */
                              /**************************************************************************************/
                              void powerOnPeripherals()
                                {
                                //Power-up
                                pinMode (POWER_PIN, OUTPUT);
                                digitalWrite (POWER_PIN, HIGH);
                                delay(1);
                                }
                              
                              /**************************************************************************************/
                              /* Allows to power OFF peripherals.                                                   */
                              /**************************************************************************************/
                              void powerOffPeripherals()
                                {
                                //Power off
                                digitalWrite (HUMIDITY_SENSOR_DIGITAL_PIN, LOW);
                                digitalWrite (POWER_PIN, LOW);
                                pinMode (HUMIDITY_SENSOR_DIGITAL_PIN, INPUT);
                                pinMode (POWER_PIN, INPUT);
                                }
                              

                              Hope it helps !

                              David.

                              A siodS 3 Replies Last reply
                              1
                              • carlierdC carlierd

                                @ar91 Please find the code I used in 3 different nodes. The good thing with the playground lib is that there is error message if dialog with DHT22 failed.

                                /**
                                 * The MySensors Arduino library handles the wireless radio link and protocol
                                 * between your home built sensors/actuators and HA controller of choice.
                                 * The sensors forms a self healing radio network with optional repeaters. Each
                                 * repeater and gateway builds a routing tables in EEPROM which keeps track of the
                                 * network topology allowing messages to be routed to nodes.
                                 *
                                 * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
                                 * Copyright (C) 2013-2015 Sensnology AB
                                 * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
                                 *
                                 * Documentation: http://www.mysensors.org
                                 * Support Forum: http://forum.mysensors.org
                                 *
                                 * This program is free software; you can redistribute it and/or
                                 * modify it under the terms of the GNU General Public License
                                 * version 2 as published by the Free Software Foundation.
                                 *
                                 */
                                
                                /**************************************************************************************/
                                /* Temperature, humidity and luminosity measurements.                                 */
                                /*                                                                                    */
                                /* Version     : 1.1.6                                                                */
                                /* Date        : 10/01/2016                                                           */
                                /* Modified by : David Carlier                                                        */
                                /**************************************************************************************/
                                /*                                ---------------                                     */
                                /*                            RST |             |  A5                                 */
                                /*                            RX  |             |  A4                                 */
                                /*                            TX  |   ARDUINO   |  A3                                 */
                                /*     RFM69 (DIO0) --------- D2  |     UNO     |  A2                                 */
                                /*            DHT22 --------- D3  |             |  A1                                 */
                                /*            Power --------- D4  | ATMEGA 328p |  A0 --------- Light dep. resistor   */
                                /*              +3v --------- VCC |             | GND --------- GND                   */
                                /*              GND --------- GND |  8MHz int.  | REF                                 */
                                /*                            OSC |             | VCC --------- +3v                   */
                                /*                            OSC |             | D13 --------- RFM69 (SCK)           */
                                /*                            D5  |             | D12 --------- RFM69 (MISO)          */
                                /*                            D6  |             | D11 --------- RFM69 (MOSI)          */
                                /*                            D7  |             | D10 --------- RFM69 (NSS)           */
                                /*                            D8  |             |  D9                                 */
                                /*                                ---------------                                     */
                                /*                                                                                    */
                                /* Power = Vcc for LDR.                                                               */
                                /* +3v = 2*AA                                                                         */
                                /*                                                                                    */
                                /**************************************************************************************/
                                
                                #include <SPI.h>
                                #include <MySensor.h>
                                #include <dht.h>
                                #include <MyTransportRFM69.h>
                                #include <MySigningAtsha204Soft.h>
                                
                                #define CHILD_ID_HUM 0
                                #define CHILD_ID_TEMP 1
                                #define CHILD_ID_LIGHT 2
                                #define CHILD_ID_VOLTAGE 3
                                #define LIGHT_SENSOR_ANALOG_PIN 0
                                #define HUMIDITY_SENSOR_DIGITAL_PIN 3
                                #define POWER_PIN 4
                                //unsigned long SLEEP_TIME = 850000; // Sleep time between reads (in milliseconds) (close to 15')
                                unsigned long SLEEP_TIME = 275000; // Sleep time between reads (in milliseconds) (close to 5')
                                
                                //Construct MySensors library
                                MySigningAtsha204Soft signer;
                                MyHwATMega328 hw;
                                MyTransportRFM69 transport;
                                MySensor gw(transport, hw, signer);
                                dht DHT;
                                MyMessage msgHum(CHILD_ID_HUM, V_HUM);
                                MyMessage msgTemp(CHILD_ID_TEMP, V_TEMP);
                                MyMessage msgLum(CHILD_ID_LIGHT, V_LEVEL);
                                MyMessage msgVolt(CHILD_ID_VOLTAGE, V_VOLTAGE);
                                
                                /**************************************************************************************/
                                /* Initialization                                                                     */
                                /**************************************************************************************/
                                void setup()
                                  {
                                  //Get time (for setup duration)
                                  #ifdef DEBUG
                                    unsigned long startTime = millis();
                                  #endif
                                
                                  //Start MySensors
                                  gw.begin();
                                
                                  //Send the Sketch Version Information to the Gateway
                                  gw.sendSketchInfo("GHAS sensor", "1.1.5");
                                
                                  //Register all sensors to gw (they will be created as child devices)
                                  gw.present(CHILD_ID_HUM, S_HUM);
                                  gw.present(CHILD_ID_TEMP, S_TEMP);
                                  gw.present(CHILD_ID_LIGHT, S_LIGHT_LEVEL);
                                  gw.present(CHILD_ID_VOLTAGE, S_MULTIMETER);
                                
                                  //Delay for DHT22
                                  delay(1500);
                                
                                  //Print setup debug
                                  #ifdef DEBUG
                                    int duration = millis() - startTime;
                                    Serial.print("[Setup duration: "); Serial.print(duration, DEC); Serial.println(" ms]");
                                  #endif
                                  }
                                
                                /**************************************************************************************/
                                /* Main loop                                                                          */
                                /**************************************************************************************/
                                void loop()
                                  {
                                  //Get time (for a complete loop)
                                  #ifdef DEBUG
                                    unsigned long startTime = millis();
                                  #endif
                                
                                  //Power on
                                  powerOnPeripherals();
                                
                                  //Get DHT22 data
                                  int dht22Result = DHT.read22(HUMIDITY_SENSOR_DIGITAL_PIN);
                                  switch (dht22Result)
                                    {
                                    case DHTLIB_OK:  
                                                //Serial.println("OK,\t");
                                                break;
                                    case DHTLIB_ERROR_CHECKSUM:
                                                #ifdef DEBUG
                                                  Serial.println("Checksum error,\t");
                                                #endif
                                                break;
                                    case DHTLIB_ERROR_TIMEOUT:
                                                #ifdef DEBUG
                                                  Serial.println("Time out error,\t");
                                                #endif
                                                break;
                                    case DHTLIB_ERROR_CONNECT:
                                                #ifdef DEBUG
                                                  Serial.println("Connect error,\t");
                                                #endif
                                                break;
                                    case DHTLIB_ERROR_ACK_L:
                                                #ifdef DEBUG
                                                  Serial.println("Ack Low error,\t");
                                                #endif
                                                break;
                                    case DHTLIB_ERROR_ACK_H:
                                                #ifdef DEBUG
                                                  Serial.println("Ack High error,\t");
                                                #endif
                                                break;
                                    default:
                                                #ifdef DEBUG
                                                  Serial.println("Unknown error,\t");
                                                #endif
                                                break;
                                    }
                                
                                  //Get temperature and humidity
                                  float temperature = 0;
                                  float humidity = 0;
                                  if (dht22Result == DHTLIB_OK)
                                    {
                                    temperature = DHT.temperature;
                                    humidity = DHT.humidity;
                                    }
                                
                                  //Get power before luminosity to use real voltage
                                  float realVoltage = getVoltage() / 100.0;
                                  int batteryPcnt = realVoltage * 100 / 3.0;
                                  if (batteryPcnt > 100) {batteryPcnt = 100;}
                                  int lux = computeIlluminance(realVoltage);
                                
                                  //Power off
                                  powerOffPeripherals();
                                
                                  //Send data to gateway
                                  gw.send(msgHum.set(humidity, 1));
                                  gw.send(msgTemp.set(temperature, 1));
                                  gw.send(msgLum.set(lux));
                                  gw.send(msgVolt.set(realVoltage, 2));
                                  gw.sendBatteryLevel(batteryPcnt);
                                
                                  //Print debug
                                  #ifdef DEBUG
                                    Serial.print(temperature, 1);
                                    Serial.print(" degC");
                                    Serial.print("   ");
                                    Serial.print(humidity, 1);
                                    Serial.print(" %");
                                    Serial.print("   ");
                                    Serial.print(lux);
                                    Serial.print(" lx");
                                    Serial.print("   ");
                                    Serial.print(realVoltage);
                                    Serial.print(" v");
                                    int duration = millis() - startTime;
                                    Serial.print("   ");
                                    Serial.print("["); Serial.print(duration, DEC); Serial.println(" ms]");
                                    Serial.flush();
                                  #endif
                                
                                  //Sleep
                                  gw.sleep(SLEEP_TIME);
                                  }
                                
                                /**************************************************************************************/
                                /* Allows to compute illuminance (in LUX) from LIGHT_SENSOR_ANALOG_PIN.               */
                                /**************************************************************************************/
                                int computeIlluminance(float realVoltage)
                                  {
                                  //Get luminosity
                                  int luminosity = analogRead(LIGHT_SENSOR_ANALOG_PIN);
                                  //Calculating the voltage in the input of the ADC
                                  double voltage = realVoltage * ((double)luminosity / 1024.0);
                                  //Calculating the resistance of the photoresistor in the voltage divider
                                  double resistance = (10.0 * realVoltage) / voltage - 10.0;
                                  //Calculating the intensity of light in lux and return it
                                  int illuminance = 255.84 * pow(resistance, -10/9);
                                  return illuminance;
                                  }
                                
                                /**************************************************************************************/
                                /* Allows to get the real Vcc (return value * 100).                                   */
                                /**************************************************************************************/
                                int getVoltage()
                                  {
                                  const long InternalReferenceVoltage = 1056L;
                                  ADMUX = (0<<REFS1) | (1<<REFS0) | (0<<ADLAR) | (1<<MUX3) | (1<<MUX2) | (1<<MUX1) | (0<<MUX0);
                                  delay(50);  // Let mux settle a little to get a more stable A/D conversion
                                  //Start a conversion  
                                  ADCSRA |= _BV( ADSC );
                                  //Wait for it to complete
                                  while (((ADCSRA & (1<<ADSC)) != 0));
                                  //Scale the value
                                  int result = (((InternalReferenceVoltage * 1023L) / ADC) + 5L) / 10L;
                                  return result;
                                  }
                                
                                /**************************************************************************************/
                                /* Allows to power ON peripherals.                                                    */
                                /**************************************************************************************/
                                void powerOnPeripherals()
                                  {
                                  //Power-up
                                  pinMode (POWER_PIN, OUTPUT);
                                  digitalWrite (POWER_PIN, HIGH);
                                  delay(1);
                                  }
                                
                                /**************************************************************************************/
                                /* Allows to power OFF peripherals.                                                   */
                                /**************************************************************************************/
                                void powerOffPeripherals()
                                  {
                                  //Power off
                                  digitalWrite (HUMIDITY_SENSOR_DIGITAL_PIN, LOW);
                                  digitalWrite (POWER_PIN, LOW);
                                  pinMode (HUMIDITY_SENSOR_DIGITAL_PIN, INPUT);
                                  pinMode (POWER_PIN, INPUT);
                                  }
                                

                                Hope it helps !

                                David.

                                A Offline
                                A Offline
                                ar91
                                wrote on last edited by
                                #22

                                @carlierd Thank you very much. I really like your comment on the top :+1:

                                1 Reply Last reply
                                0
                                • rsachocR Offline
                                  rsachocR Offline
                                  rsachoc
                                  wrote on last edited by
                                  #23

                                  Progress!

                                  http://imgur.com/zRvXvrN
                                  http://imgur.com/KpB7daz

                                  A question though. To get to this point, I copied the pictures posted above, but where do I now add these resistors?

                                  http://imgur.com/6mKJcgE

                                  Also, if I want to add a 2AA battery cage, where do I connect the red and black wires to?

                                  Thanks! And sorry for the newb questions!

                                  m26872M 1 Reply Last reply
                                  0
                                  • GertSandersG Offline
                                    GertSandersG Offline
                                    GertSanders
                                    Hardware Contributor
                                    wrote on last edited by
                                    #24

                                    @rsachoc What you show are not resistors, they look like capacitors. 104 means 100nF (I think). Can you measure their value ?

                                    1 Reply Last reply
                                    0
                                    • carlierdC carlierd

                                      @ar91 Please find the code I used in 3 different nodes. The good thing with the playground lib is that there is error message if dialog with DHT22 failed.

                                      /**
                                       * The MySensors Arduino library handles the wireless radio link and protocol
                                       * between your home built sensors/actuators and HA controller of choice.
                                       * The sensors forms a self healing radio network with optional repeaters. Each
                                       * repeater and gateway builds a routing tables in EEPROM which keeps track of the
                                       * network topology allowing messages to be routed to nodes.
                                       *
                                       * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
                                       * Copyright (C) 2013-2015 Sensnology AB
                                       * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
                                       *
                                       * Documentation: http://www.mysensors.org
                                       * Support Forum: http://forum.mysensors.org
                                       *
                                       * This program is free software; you can redistribute it and/or
                                       * modify it under the terms of the GNU General Public License
                                       * version 2 as published by the Free Software Foundation.
                                       *
                                       */
                                      
                                      /**************************************************************************************/
                                      /* Temperature, humidity and luminosity measurements.                                 */
                                      /*                                                                                    */
                                      /* Version     : 1.1.6                                                                */
                                      /* Date        : 10/01/2016                                                           */
                                      /* Modified by : David Carlier                                                        */
                                      /**************************************************************************************/
                                      /*                                ---------------                                     */
                                      /*                            RST |             |  A5                                 */
                                      /*                            RX  |             |  A4                                 */
                                      /*                            TX  |   ARDUINO   |  A3                                 */
                                      /*     RFM69 (DIO0) --------- D2  |     UNO     |  A2                                 */
                                      /*            DHT22 --------- D3  |             |  A1                                 */
                                      /*            Power --------- D4  | ATMEGA 328p |  A0 --------- Light dep. resistor   */
                                      /*              +3v --------- VCC |             | GND --------- GND                   */
                                      /*              GND --------- GND |  8MHz int.  | REF                                 */
                                      /*                            OSC |             | VCC --------- +3v                   */
                                      /*                            OSC |             | D13 --------- RFM69 (SCK)           */
                                      /*                            D5  |             | D12 --------- RFM69 (MISO)          */
                                      /*                            D6  |             | D11 --------- RFM69 (MOSI)          */
                                      /*                            D7  |             | D10 --------- RFM69 (NSS)           */
                                      /*                            D8  |             |  D9                                 */
                                      /*                                ---------------                                     */
                                      /*                                                                                    */
                                      /* Power = Vcc for LDR.                                                               */
                                      /* +3v = 2*AA                                                                         */
                                      /*                                                                                    */
                                      /**************************************************************************************/
                                      
                                      #include <SPI.h>
                                      #include <MySensor.h>
                                      #include <dht.h>
                                      #include <MyTransportRFM69.h>
                                      #include <MySigningAtsha204Soft.h>
                                      
                                      #define CHILD_ID_HUM 0
                                      #define CHILD_ID_TEMP 1
                                      #define CHILD_ID_LIGHT 2
                                      #define CHILD_ID_VOLTAGE 3
                                      #define LIGHT_SENSOR_ANALOG_PIN 0
                                      #define HUMIDITY_SENSOR_DIGITAL_PIN 3
                                      #define POWER_PIN 4
                                      //unsigned long SLEEP_TIME = 850000; // Sleep time between reads (in milliseconds) (close to 15')
                                      unsigned long SLEEP_TIME = 275000; // Sleep time between reads (in milliseconds) (close to 5')
                                      
                                      //Construct MySensors library
                                      MySigningAtsha204Soft signer;
                                      MyHwATMega328 hw;
                                      MyTransportRFM69 transport;
                                      MySensor gw(transport, hw, signer);
                                      dht DHT;
                                      MyMessage msgHum(CHILD_ID_HUM, V_HUM);
                                      MyMessage msgTemp(CHILD_ID_TEMP, V_TEMP);
                                      MyMessage msgLum(CHILD_ID_LIGHT, V_LEVEL);
                                      MyMessage msgVolt(CHILD_ID_VOLTAGE, V_VOLTAGE);
                                      
                                      /**************************************************************************************/
                                      /* Initialization                                                                     */
                                      /**************************************************************************************/
                                      void setup()
                                        {
                                        //Get time (for setup duration)
                                        #ifdef DEBUG
                                          unsigned long startTime = millis();
                                        #endif
                                      
                                        //Start MySensors
                                        gw.begin();
                                      
                                        //Send the Sketch Version Information to the Gateway
                                        gw.sendSketchInfo("GHAS sensor", "1.1.5");
                                      
                                        //Register all sensors to gw (they will be created as child devices)
                                        gw.present(CHILD_ID_HUM, S_HUM);
                                        gw.present(CHILD_ID_TEMP, S_TEMP);
                                        gw.present(CHILD_ID_LIGHT, S_LIGHT_LEVEL);
                                        gw.present(CHILD_ID_VOLTAGE, S_MULTIMETER);
                                      
                                        //Delay for DHT22
                                        delay(1500);
                                      
                                        //Print setup debug
                                        #ifdef DEBUG
                                          int duration = millis() - startTime;
                                          Serial.print("[Setup duration: "); Serial.print(duration, DEC); Serial.println(" ms]");
                                        #endif
                                        }
                                      
                                      /**************************************************************************************/
                                      /* Main loop                                                                          */
                                      /**************************************************************************************/
                                      void loop()
                                        {
                                        //Get time (for a complete loop)
                                        #ifdef DEBUG
                                          unsigned long startTime = millis();
                                        #endif
                                      
                                        //Power on
                                        powerOnPeripherals();
                                      
                                        //Get DHT22 data
                                        int dht22Result = DHT.read22(HUMIDITY_SENSOR_DIGITAL_PIN);
                                        switch (dht22Result)
                                          {
                                          case DHTLIB_OK:  
                                                      //Serial.println("OK,\t");
                                                      break;
                                          case DHTLIB_ERROR_CHECKSUM:
                                                      #ifdef DEBUG
                                                        Serial.println("Checksum error,\t");
                                                      #endif
                                                      break;
                                          case DHTLIB_ERROR_TIMEOUT:
                                                      #ifdef DEBUG
                                                        Serial.println("Time out error,\t");
                                                      #endif
                                                      break;
                                          case DHTLIB_ERROR_CONNECT:
                                                      #ifdef DEBUG
                                                        Serial.println("Connect error,\t");
                                                      #endif
                                                      break;
                                          case DHTLIB_ERROR_ACK_L:
                                                      #ifdef DEBUG
                                                        Serial.println("Ack Low error,\t");
                                                      #endif
                                                      break;
                                          case DHTLIB_ERROR_ACK_H:
                                                      #ifdef DEBUG
                                                        Serial.println("Ack High error,\t");
                                                      #endif
                                                      break;
                                          default:
                                                      #ifdef DEBUG
                                                        Serial.println("Unknown error,\t");
                                                      #endif
                                                      break;
                                          }
                                      
                                        //Get temperature and humidity
                                        float temperature = 0;
                                        float humidity = 0;
                                        if (dht22Result == DHTLIB_OK)
                                          {
                                          temperature = DHT.temperature;
                                          humidity = DHT.humidity;
                                          }
                                      
                                        //Get power before luminosity to use real voltage
                                        float realVoltage = getVoltage() / 100.0;
                                        int batteryPcnt = realVoltage * 100 / 3.0;
                                        if (batteryPcnt > 100) {batteryPcnt = 100;}
                                        int lux = computeIlluminance(realVoltage);
                                      
                                        //Power off
                                        powerOffPeripherals();
                                      
                                        //Send data to gateway
                                        gw.send(msgHum.set(humidity, 1));
                                        gw.send(msgTemp.set(temperature, 1));
                                        gw.send(msgLum.set(lux));
                                        gw.send(msgVolt.set(realVoltage, 2));
                                        gw.sendBatteryLevel(batteryPcnt);
                                      
                                        //Print debug
                                        #ifdef DEBUG
                                          Serial.print(temperature, 1);
                                          Serial.print(" degC");
                                          Serial.print("   ");
                                          Serial.print(humidity, 1);
                                          Serial.print(" %");
                                          Serial.print("   ");
                                          Serial.print(lux);
                                          Serial.print(" lx");
                                          Serial.print("   ");
                                          Serial.print(realVoltage);
                                          Serial.print(" v");
                                          int duration = millis() - startTime;
                                          Serial.print("   ");
                                          Serial.print("["); Serial.print(duration, DEC); Serial.println(" ms]");
                                          Serial.flush();
                                        #endif
                                      
                                        //Sleep
                                        gw.sleep(SLEEP_TIME);
                                        }
                                      
                                      /**************************************************************************************/
                                      /* Allows to compute illuminance (in LUX) from LIGHT_SENSOR_ANALOG_PIN.               */
                                      /**************************************************************************************/
                                      int computeIlluminance(float realVoltage)
                                        {
                                        //Get luminosity
                                        int luminosity = analogRead(LIGHT_SENSOR_ANALOG_PIN);
                                        //Calculating the voltage in the input of the ADC
                                        double voltage = realVoltage * ((double)luminosity / 1024.0);
                                        //Calculating the resistance of the photoresistor in the voltage divider
                                        double resistance = (10.0 * realVoltage) / voltage - 10.0;
                                        //Calculating the intensity of light in lux and return it
                                        int illuminance = 255.84 * pow(resistance, -10/9);
                                        return illuminance;
                                        }
                                      
                                      /**************************************************************************************/
                                      /* Allows to get the real Vcc (return value * 100).                                   */
                                      /**************************************************************************************/
                                      int getVoltage()
                                        {
                                        const long InternalReferenceVoltage = 1056L;
                                        ADMUX = (0<<REFS1) | (1<<REFS0) | (0<<ADLAR) | (1<<MUX3) | (1<<MUX2) | (1<<MUX1) | (0<<MUX0);
                                        delay(50);  // Let mux settle a little to get a more stable A/D conversion
                                        //Start a conversion  
                                        ADCSRA |= _BV( ADSC );
                                        //Wait for it to complete
                                        while (((ADCSRA & (1<<ADSC)) != 0));
                                        //Scale the value
                                        int result = (((InternalReferenceVoltage * 1023L) / ADC) + 5L) / 10L;
                                        return result;
                                        }
                                      
                                      /**************************************************************************************/
                                      /* Allows to power ON peripherals.                                                    */
                                      /**************************************************************************************/
                                      void powerOnPeripherals()
                                        {
                                        //Power-up
                                        pinMode (POWER_PIN, OUTPUT);
                                        digitalWrite (POWER_PIN, HIGH);
                                        delay(1);
                                        }
                                      
                                      /**************************************************************************************/
                                      /* Allows to power OFF peripherals.                                                   */
                                      /**************************************************************************************/
                                      void powerOffPeripherals()
                                        {
                                        //Power off
                                        digitalWrite (HUMIDITY_SENSOR_DIGITAL_PIN, LOW);
                                        digitalWrite (POWER_PIN, LOW);
                                        pinMode (HUMIDITY_SENSOR_DIGITAL_PIN, INPUT);
                                        pinMode (POWER_PIN, INPUT);
                                        }
                                      

                                      Hope it helps !

                                      David.

                                      A Offline
                                      A Offline
                                      ar91
                                      wrote on last edited by
                                      #25

                                      @carlierd Are you running your Atmega at 1Mhz, Because I tried to use your sketch and i am getting "Checksum Error".

                                      carlierdC 1 Reply Last reply
                                      0
                                      • rsachocR Offline
                                        rsachocR Offline
                                        rsachoc
                                        wrote on last edited by rsachoc
                                        #26

                                        @GertSanders indeed they are capacitors (silly me) - apparently they are 0.1uf - the black one I have already soldered is 4.7uf

                                        1 Reply Last reply
                                        0
                                        • A ar91

                                          @carlierd Are you running your Atmega at 1Mhz, Because I tried to use your sketch and i am getting "Checksum Error".

                                          carlierdC Offline
                                          carlierdC Offline
                                          carlierd
                                          wrote on last edited by
                                          #27

                                          @ar91 said:

                                          @carlierd Are you running your Atmega at 1Mhz, Because I tried to use your sketch and i am getting "Checksum Error".

                                          No, I am working at 8 MHz (internal). Perhaps your DHT is out of order ? You try with another one ?

                                          David.

                                          1 Reply Last reply
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