Battery powered PIR and temp/humid sensor

[tomkxy]

@hek

Thanks! That confirms my understanding.

[Haakon]

@tomkxy: Have you gathered some experiences with this setup over time? And would you mind sharing the Arduino sketch you are using?

I am hoping to do more or less the same with Sensebenders and PIRs, and I am new to electronics of this sort.

[tomkxy]

@Haakon I have one of these sensor in place since about half a year and it is working well. Last battery change is about 4 month ago.

Please find the sketch below which requires some cleanup.

/*
Multisensor Sketch

Author: Thomas Krebs, thkrebs@gmx.de

This sketch reads temperature, humidity, light and presence.
It is based on the various examples sketches from SparkFun and MySensors 

It uses the following sensors:
Light           - TSL2561
Temp&Humidity   - HTU21D
Presence 

HTU21D and TLS2561 need to connect the I2C pins (SCL and SDA) to your Arduino.
The pins are different on different Arduinos:

                    SDA    SCL
Any Arduino         "SDA"  "SCL"
Uno, Redboard, Pro  A4     A5
Mega2560, Due       20     21
Leonardo            2      3

*/
#define MY_DEBUG_VERBOSE_SIGNING //!< Enable signing related debug prints to serial monitor

#define MY_SIGNING_FEATURE
#define MY_SIGNING_ATSHA204
#define MY_SIGNING_REQUEST_SIGNATURES

#define MY_DEBUG
#define MY_NODE_ID              26
#define MY_RADIO_NRF24
#define BATT_SENSOR

#include <MySensor.h>
#include <TSL2561.h>
#include <SparkFunHTU21D.h>

#include <SPI.h>
#include <Wire.h>
#include <avr/power.h>

#define VERSION           "1.4"
#define SKETCH_NAME       "Multisensor A"

#define TEMP_CHILD_ID   1
#define HUM_CHILD_ID    2
#define LIGHT_CHILD_ID  3
#define MOTION_CHILD_ID 4

// Uncomment the line below, to transmit battery voltage as a normal sensor value
#define BATT_SENSOR    199
#define MAX_VOLTAGE    1316
#define MIN_VOLTAGE    890     // it seems that about 0.89 V the sensor stops working

// How many milli seconds between each measurement
#define MEASURE_INTERVAL 120000

// FORCE_TRANSMIT_INTERVAL, this number of times of wakeup, the sensor is forced to report all values to the controller
#define FORCE_TRANSMIT_INTERVAL 30 

// When MEASURE_INTERVAL is 60000 and FORCE_TRANSMIT_INTERVAL is 30, we force a transmission every 30 minutes.
// Between the forced transmissions a tranmission will only occur if the measured value differs from the previous measurement

// HUMI_TRANSMIT_THRESHOLD tells how much the humidity should have changed since last time it was transmitted. Likewise with
// TEMP_TRANSMIT_THRESHOLD for temperature threshold.
#define HUMI_TRANSMIT_THRESHOLD   0.5
#define TEMP_TRANSMIT_THRESHOLD   0.5
#define LIGHT_TRANSMIT_THRESHOLD  0.3    // relative change


// Pin definitions
#define LED_PIN            13            // TODO: need to check that
#define BATTERY_SENSE_PIN  A0            // select the input pin for the battery sense point
#define MOTION_SENSOR      3             // The digital input you attached your motion sensor.  (Only 2 and 3 generates interrupt!)
#define INTERRUPT          1             // Usually the interrupt = pin -2 (on uno/nano anyway)

// Global settings
int tempMeasureCount = 0;
int lightMeasureCount = 0;

int sendBattery = 0;
boolean isMetric = true;
boolean highfreq = true;
boolean motionDetected = false;
int repeats = 2;

// Storage of old measurements
float lastTemperature = -100;
float lastHumidity = -100;
long  lastBattery = -100;
long  lastLight = -5000;
int   lastTripped = -1; 

int   motionTrips = 0;  // count the number of cont. motion trips

HTU21D myHumidity;
TSL2561 myLight(TSL2561_ADDR_FLOAT); 

// Sensor messages
MyMessage msgTemp(TEMP_CHILD_ID,V_TEMP);
MyMessage msgHum(HUM_CHILD_ID,V_HUM);
MyMessage msgLight(LIGHT_CHILD_ID,V_LEVEL);
MyMessage msg(MOTION_CHILD_ID, V_TRIPPED);


#ifdef BATT_SENSOR
MyMessage msgBatt(BATT_SENSOR, V_VOLTAGE);
#endif


/****************************************************
 *
 * Setup code 
 *
 ****************************************************/
void setup()  
{ 
  pinMode(LED_PIN, OUTPUT);
  Serial.print(F(SKETCH_NAME));
  Serial.println(VERSION);
  Serial.flush();
  
  
#ifdef MY_SIGNING_ATSHA204_PIN
  // Make sure that ATSHA204 is not floating
  pinMode(MY_SIGNING_ATSHA204_PIN, INPUT);
  digitalWrite(MY_SIGNING_ATSHA204_PIN, HIGH);
#endif  
  
  // use the 1.1 V internal reference
  analogReference(INTERNAL);

  // setup sensors
  setup_htu21d();
  
  delay(100);
  setup_tls2561(); 
  delay(500);
  
  // setup motion sensor 
  pinMode(MOTION_SENSOR, INPUT);    
  Serial.println(F("Setup complete..."));
}


void presentation()  {
  // Send the sketch version information to the gateway and Controller
  sendSketchInfo(SKETCH_NAME, VERSION);

  // Present all sensors to controller
  present(TEMP_CHILD_ID, S_TEMP);
  present(HUM_CHILD_ID, S_HUM);
//  present(LIGHT_CHILD_ID,S_LIGHT_LEVEL);
  present(MOTION_CHILD_ID, S_MOTION);


#ifdef BATT_SENSOR
  present(BATT_SENSOR, S_POWER);
#endif

  isMetric = getConfig().isMetric;
#ifdef MY_DEBUG
  Serial.print(F("isMetric: ")); Serial.println(isMetric);
#endif

  Serial.flush();
  Serial.println(F(" - Online!"));
}


/***********************************************
/* Setup HTU21d
 ***********************************************/
void setup_htu21d() {
  myHumidity.begin();
#ifdef MY_DEBUG  
  Serial.println("Setup temp/humid sensor completed");
#endif
}


/***********************************************
/* Setup TLS2561
 ***********************************************/
void setup_tls2561() {
 
  if (myLight.begin()) {
    Serial.println(F("Found light sensor"));
  } else {
    Serial.println(F("Light Sensor not found - cont. anyway"));
  }
  myLight.setGain(TSL2561_GAIN_0X);          // set 16x gain (for dim situations)
  
  // Changing the integration time gives you a longer time over which to sense light
  // longer timelines are slower, but are good in very low light situtations!
  //tsl.setTiming(TSL2561_INTEGRATIONTIME_13MS);  // shortest integration time (bright light)
  myLight.setTiming(TSL2561_INTEGRATIONTIME_101MS);  // medium integration time (medium light)
  //tsl.setTiming(TSL2561_INTEGRATIONTIME_402MS);  // longest integration time (dim light)
  
}

/***********************************************
 *
 *  Main loop function
 *
 ***********************************************/
void loop()     
{ 
  tempMeasureCount++;
  lightMeasureCount++;
  sendBattery++;
  bool forceTransmit = false;

  if (motionDetected) {
    sendMotion(false);  // do not force transmission unless motion status has changed
    motionDetected = false;
  }
  
  // do not enter into sensor data gathering on each motion tripped
  if ((!motionDetected) || (motionTrips > 3)) {
    motionTrips = 0; // avoid starvation of temp measure in case we have a lot of motion
    
    // I do the battery check at the beginning
    if (sendBattery > 60) {
       sendBattLevel(forceTransmit); // Not needed to send battery info that often
       sendBattery = 0;
    }
    
    if ((lightMeasureCount > FORCE_TRANSMIT_INTERVAL) || (tempMeasureCount > FORCE_TRANSMIT_INTERVAL) ) { // force a transmission
      forceTransmit = true; 
      tempMeasureCount = 0;
      lightMeasureCount = 0;
    }
  
    // Get & send sensor data
    wait(200);
    sendTempHumidityMeasurement(forceTransmit);
    wait(200);
    sendLightLevelMeasurement(forceTransmit);
    wait(200);
    sendMotion(forceTransmit);
  } 
  wait(100);  // I don't know whether that is really required; however I have the impression that shutting down the radio leads to
                 // problems in the communication when using signatures
  Serial.println("going to sleep");
  if (sleep(INTERRUPT,RISING, MEASURE_INTERVAL)) {
    motionDetected = true;
    motionTrips++;
  }
  Serial.print("Motion detected="); Serial.println(motionDetected);
}

/*********************************************
 *
 * Sends state of motion sensor
 *
 * Parameters
 * - force : Forces transmission of a value (even if it's the same as previous measurement)
 *
 *********************************************/
void sendMotion(bool force) {
 
  bool tx = force;
  
  // Read digital motion value
  bool tripped = digitalRead(MOTION_SENSOR) == HIGH; 
  Serial.print(F("Tripped: ")); Serial.println(tripped);
  
  if (lastTripped != tripped) tx = true;
  if (tx) {
    resend(msg.set(tripped?"1":"0"),repeats);  // Send tripped value to gw 
    lastTripped = tripped;
  }
}

/*********************************************
 *
 * Sends temperature and humidity from HTU21D sensor
 *
 * Parameters
 * - force : Forces transmission of a value (even if it's the same as previous measurement)
 *
 *********************************************/
void sendTempHumidityMeasurement(bool force) 
{
    bool tx = force;
    
    float hum = myHumidity.readHumidity();
    float temp = myHumidity.readTemperature();
    
    Serial.print(F("lastTemperature: ")); Serial.println(lastTemperature);
    Serial.print(F("lastHumidity: ")); Serial.println(lastHumidity);
    
    float diffTemp = abs(lastTemperature - temp);
    float diffHum = abs(lastHumidity - hum);

#ifdef MY_DEBUG
    Serial.print(F("TempDiff :"));Serial.println(diffTemp);
    Serial.print(F("HumDiff  :"));Serial.println(diffHum); 
#endif

    if (isnan(diffHum)) tx = true; 
    if (diffTemp > TEMP_TRANSMIT_THRESHOLD) tx = true;
    if (diffHum >= HUMI_TRANSMIT_THRESHOLD) tx = true;

    if (tx) {
      tempMeasureCount = 0;
      resend(msgTemp.setSensor(TEMP_CHILD_ID).set(temp,1),repeats); 
      wait(20);
      resend(msgHum.setSensor(HUM_CHILD_ID).set(hum,1),repeats); 
      lastTemperature = temp;
      lastHumidity = hum;   
    }
}


/*********************************************
 *
 * Sends light level from TLS6512 sensor
 *
 * Parameters
 * - force : Forces transmission of a value (even if it's the same as previous measurement)
 *
 *********************************************/
void sendLightLevelMeasurement(bool force) {
  bool tx = force;
  
  uint32_t lum = myLight.getFullLuminosity();
  uint16_t ir, full;
  ir = lum >> 16;
  full = lum & 0xFFFF;
  
  Serial.print(F("IR: ")); Serial.print(ir);   Serial.print(F("\t\t"));
  Serial.print(F("Full: ")); Serial.print(full);   Serial.print(F("\t"));
  Serial.print(F("Visible: ")); Serial.print(full - ir);   Serial.print(F("\t"));
  
  double lux = myLight.calculateLux(full, ir);
  Serial.print(F("Lux: ")); Serial.println(lux);
  float diffLux = abs(lastLight - lux);
#ifdef MY_DEBUG
    Serial.print(F("Lux difference since last measurement: ")); Serial.println((float)diffLux/abs(lastLight));    
#endif
    if (isnan(diffLux)) tx = true; 
    if (diffLux/abs(lastLight)  >= LIGHT_TRANSMIT_THRESHOLD) tx = true;

    if (tx) {
      lightMeasureCount = 0;
      resend(msgLight.setSensor(LIGHT_CHILD_ID).set(lux,1),repeats);
      lastLight = lux;
    }
}


/*********************************************
 * Prints error on I2C comm bus
 *********************************************/
void printError(byte error)
  // If there's an I2C error, this function will
  // print out an explanation.
{
  Serial.print(F("I2C error: "));
  Serial.print(error,DEC);
  Serial.print(F(", "));
  
  switch(error)
  {
    case 0:
      Serial.println(F("success"));
      break;
    case 1:
      Serial.println(F("data too long for transmit buffer"));
      break;
    case 2:
      Serial.println(F("received NACK on address (disconnected?)"));
      break;
    case 3:
      Serial.println(F("received NACK on data"));
      break;
    case 4:
      Serial.println(F("other error"));
      break;
    default:
      Serial.println(F("unknown error"));
  }
}


/********************************************
 *
 * Sends battery information (battery percentage)
 *
 * Parameters
 * - force : Forces transmission of a value
 *
 *******************************************/
void sendBattLevel(bool force)
{
  if (force) lastBattery = -1;
  long batteryV =  analogRead(BATTERY_SENSE_PIN);  
  for (int i = 1; i<5; i++) {
    long newSample = analogRead(BATTERY_SENSE_PIN); //readVcc();
    batteryV -= batteryV / (i+1);
    batteryV += newSample / (i+1);   
  }
   
   // 10M, 2,86M divider across battery and using internal ADC ref of 1.1V
   // Sense point is bypassed with 0.1 uF cap to reduce noise at that point
   // ((10+4,7)/4,7)*1.1 = 3.4404255
   // 3.4404255/1023 = Volts per bit = 0.003630748

  long vcc  = batteryV * 3.3630748;
  if (vcc != lastBattery) {
    lastBattery = vcc;

#ifdef BATT_SENSOR
    resend(msgBatt.set(vcc),repeats);
#endif
    // Calculate on the fully charged cell. Since I have a step-up in place I go as low as possible no offset for minimum
   sendBatteryLevel(  ((vcc-MIN_VOLTAGE)*10.0)/((MAX_VOLTAGE-MIN_VOLTAGE)*10.0) *100.0);
  }
}


/********************************************
 *
 * Send message, resend on error
 *
 * Parameters
 * - msg : message to send
 * - repeats: number of repetitions
 *
 *******************************************/
void resend(MyMessage &msg, int repeats)
{
  int repeat = 0;
  int repeatdelay = 0;
  boolean sendOK = false;

  while ((sendOK == false) and (repeat < repeats)) {
    if (send(msg)) {
      sendOK = true;
    } else {
      sendOK = false;
      Serial.print(F("Send ERROR "));
      Serial.println(repeat);
      repeatdelay += random(50,200);
    } 
    repeat++; 
    delay(repeatdelay);
  }
}


/*******************************************
 *
 * Internal battery ADC measuring 
 *
 *******************************************/
long readVcc() {
  // Read 1.1V reference against AVcc
  // set the reference to Vcc and the measurement to the internal 1.1V reference
  #if defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
    ADMUX = _BV(REFS0) | _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
  #elif defined (__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
    ADMUX = _BV(MUX5) | _BV(MUX0);
  #elif defined (__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
    ADcdMUX = _BV(MUX3) | _BV(MUX2);
  #else
    ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
  #endif  
 
  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
}

[Haakon]

Thanks, @tomkxy, fantastic! I will be trying it our shortly, as soon as I got those PIRs working on 3V.

[tomkxy]

@Haakon Regarding the PIRs: There are a couple of postings in the Internet or I think even in this forum. For example, have a look here: http://randomnerdtutorials.com/modifying-cheap-pir-motion-sensor-to-work-at-3-3v/

[LastSamurai]

@tomkxy How did you power it though? I wanted to use a battery (or several ones) that might fall under 3.3V when used. So I decided to use a step-up converter but that seems to introduce too much noise, so I get false positives from the pir. From a stable 3.3V source it worked just fine.

[tomkxy]

@LastSamurai I powered it through 3.3v step up with one AA battery. I cannot confirm that I get false positives.

[martinhjelmare]

@tomkxy

What range on the PIR do you get on 3.3 V?

[tomkxy]

Around 4 meters. However, this puppy is sitting in my entrance which is rather narrow.

[LastSamurai]

@tomkxy said:

@LastSamurai I powered it through 3.3v step up with one AA battery. I cannot confirm that I get false positives.

Nice, what PIR and what step up did you use? Hopefully I can get the same ones too ;)

[tomkxy]

I used this one one which is rather expensive. I do not remember, however whether I bought really at Sparkfun or some other place. That were one of my first purchases when I started with all that crazy stuff :-)

[Mark Swift]

Hi @tomkxy

I'm going to add one of these sensors myself, looks like you've done the hard work...

Could I ask what board you are using, perhaps a simple schematic too if you find a moment? I have a bunch of Nano's, some light sensors (BH1750) and temperature sensors (DS18B20's) - I presume I can swap over the code as required. Thankfully I also have a number of those exact step ups!

[tomkxy]

@Mark-Swift I used a ProMini 3.3v. Unfortunately, I have no schematic. Since I used breakout boards anyway this is not a big deal. You connect those boards to your power, ground and a digital pin or on SCA, SCL pins. I don't know what the power consumption of the Nano's is. So that is something you have to try out.

[alexsh1]

@tomkxy it is a few mA while sleeping. This means that it has to be modified (no VDO and no LED) - consumption drops to a reasonable 160uA or even below.