Slim Node Si7021 sensor example

[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.

[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?

[m26872]

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

[carlierd]

@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 !

[carlierd]

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

David.

[ar91]

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

[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.

[ar91]

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

[rsachoc]

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!

[GertSanders]

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

[ar91]

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

[rsachoc]

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

[carlierd]

@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.

[rsachoc]

Bump, can anyone advise on how I got about finding out where I need to solder the resistors on? So far I've just soldered the 4.7uf capacitor, as can be seen from the pics. But I'm struggling to find out where I need to solder the other capacitor's I have (from the BOM).

[m26872]

@rsachoc C1,C2,C3 are clearly marked at top layer silkscreen. You'll see them in the middle of the uC socket if you look at your 2nd picture in you last post above. C5 is visible next to the 4.7u cap, in the 3rd picture of my first post in this thread.

[m26872]

@rsachoc said:

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

First picture in first post of this thread should be enough. Connect (+) to Vcc and (-) to Gnd.

[rsachoc]

Thanks, apologies, I really should have looked at my board, I was searching for the answer in the main slim node thread and I think i was looking at older boards and couldn't for the life of me find where C3 is!

[m26872]

@rsachoc I'm sorry, I know I need to update those old pictures.

[rsachoc]

@m26872 no problem, not your fault at all, mine for being a newbie. So much so that my first attempt resulted in me soldering the capacitor to the wrong hole, so I've had to abandon my first attempt. You live, you learn, next time I'll double check.

[m26872]

@rsachoc Yes. Double check polarity of the 4.7uF cap.