Power consumption too high on Whispernode + CR2032 battery

Using Arduino Project Guidance
#1

Hello,

I recently configured multiple Whispernode sensors (https://wisen.com.au/) around the house but the power handling is not so good. Whispernode is based on Atmel AVR ATMega328p. I am using CR2032 battery and the battery is drained in approximately 8 days allthough I know people have got better results with this setup.

Here is my code from a node that measures temperature and humidity via a DHT22 sensor and sends it to a master node using 433MHZ radio: https://p.dnaip.fi/a3jz8vPzCdnZ4pbU

Is there anything I can improve / optimize the code to make the battery last longer?

Cheers.

#2

(deleted)

#3

Ok, my apologies I see the secure aspect on that. Here is the code:

/*
* Bedroom node
*/
#include <T2WhisperNode.h>
#include <LowPower.h>
#include <DHT.h>
#include <RH_RF69.h>
 
// DHT 22
#define DHT_PWD_PIN A2 // We power the DHT11 via a MCU GPIO so we can control when it's up or not
#define DHT_DATA_PIN A1
#define DHT_TYPE DHT22
DHT dht(DHT_DATA_PIN, DHT_TYPE);
 
// SPI Flash
T2Flash myFlash;
 
// RFM69 Radio
#define RADIO_FREQUENCY 433.0
#define RADIO_TX_POWER 13
#define RADIO_ENCRYPTION_KEY { 0x00, 0x03, 0x01, 0x00, 0x01, 0x09, 0x08, 0x06, 0x02, 0x05, 0x00, 0x05, 0x01, 0x09, 0x08, 0x05 }
RH_RF69 myRadio;
uint8_t radioBuf[(T2_MESSAGE_HEADERS_LEN + T2_MESSAGE_MAX_DATA_LEN)];
 
// T2 Message
T2Message myMsg;
#define nodeAddr 0x88
#define baseAddr 0x0B
 
void setup()
{
  // Serial
  Serial.begin(115200);
  Serial.println(F("Example: DHT22 Sensor Node"));
 
  Serial.println(F("Putting Radio and SPI Flash to Sleep"));
  // Radio - Initialize the radio and put it to sleep to save energy
  myRadio.init();
  myRadio.setModemConfig(RH_RF69::FSK_Rb125Fd125);
  myRadio.setFrequency(RADIO_FREQUENCY);
  uint8_t myRadioEncryptionKey[] = RADIO_ENCRYPTION_KEY;
  myRadio.setEncryptionKey(myRadioEncryptionKey);
  myRadio.setTxPower(RADIO_TX_POWER);
  myRadio.sleep();
 
  // Flash - We're not using, so just power it down to save energy
  myFlash.init(T2_WPN_FLASH_SPI_CS);
  myFlash.powerDown();
 
  // DHT22
  digitalWrite(DHT_PWD_PIN, LOW);
  pinMode(DHT_PWD_PIN, OUTPUT);
  dht.begin();
 
  // Setup the Blue LED pin
  digitalWrite(T2_WPN_LED_1, LOW); // Set LED to Off
  pinMode(T2_WPN_LED_1, OUTPUT);   // Set LED pint to OUTPUT
 
  // Blink the blue led once at the boot
  digitalWrite(T2_WPN_LED_1, HIGH);
  delay(5);
  digitalWrite(T2_WPN_LED_1, LOW);
 
}
 
uint8_t loopCount = 75;
 
void loop()
{
 
  // We only do something every 38 sleep cycles (38 * 8 = 300 seconds)
  if(loopCount == 75)
  {
 
    // Do some work!
    sendTestVoltage(1);
    sendTestVoltage(2);
    sendTempHumidity();
 
    loopCount = 0;
 
  }
 
  // Using Low-Power library to put the MCU to Sleep
  LowPower.powerDown(SLEEP_8S, ADC_OFF, BOD_OFF);
  loopCount++;
 
}
 
void sendTempHumidity()
{
  // Turn the Sensor ON
  digitalWrite(DHT_PWD_PIN, HIGH);
 
  //Wait a bit for the sensor to wake up
  delay(750);
 
  // Read temperature as Celsius * 100 to remove any decimals
  // False, True means we don't want Fahrenheit and we want to force the reading.
  int16_t t = dht.readTemperature(false, true) * 100;
 
  // * 100 to remove any decimals. We do not force the reading, so we use the last info
  uint16_t h = dht.readHumidity() * 100;
 
  //Turn the Sensor OFF
  digitalWrite(DHT_PWD_PIN, LOW);
 
  
  // For Debbuging only
  //Serial.println(t);
  //Serial.println(h);
  //delay(10);
 
 
  // Prepare Temperature Message and send
  myMsg.cmd = 0x03; // Return Data
  myMsg.idx = 0x05; // HID and Sensors
  myMsg.sdx = 0x0a; // Temperature
  myMsg.data[0] = 0x01; // Operation Temp in Celcius * 100
  myMsg.data[1] = 0x01; // Sensor ID - we only have 1 in this case
  myMsg.data[2] = t >> 8;
  myMsg.data[3] = t;
  myMsg.len = 4; // Update length
  sendMessage();
 
  // Now change message details with the Humidity details and send it
  myMsg.cmd = 0x03; // Return Data
  myMsg.idx = 0x05; // HID and Sensors
  myMsg.sdx = 0x0b; // Humidity
  myMsg.data[0] = 0x01; // Operation Humidity in % * 100
  myMsg.data[1] = 0x01; // Sensor ID - we only have 1 in this case
  myMsg.data[2] = h >> 8;
  myMsg.data[3] = h;
  myMsg.len = 4; // Update length
  sendMessage();
 
}
 
void sendTestVoltage(uint8_t supply)
{
  uint16_t voltage = 0;
 
  // Get Voltage readings from supply/battery
  if(supply == 1)
  {
    voltage = T2Utils::readVoltage(T2_WPN_VBAT_VOLTAGE, T2_WPN_VBAT_CONTROL);
    myMsg.sdx = 0x64; // Battery
  }
 
  if(supply == 2)
  {
    voltage = T2Utils::readVoltage(T2_WPN_VIN_VOLTAGE, T2_WPN_VIN_CONTROL);
    myMsg.sdx = 0x65; // Supply
  }
 
  // Fill the message details and send it
  myMsg.cmd = 0x03; // Return Data
  myMsg.idx = 0x06; // Node Info
  myMsg.data[0] = 0x01; // Operation Last Reading
  myMsg.data[1] = 0x01; // Battery/Supply Index, if multiple supplies
  myMsg.data[2] = voltage >> 8;
  myMsg.data[3] = voltage;
  myMsg.len = 4; // Update length
 
  sendMessage();
 
}
 
void sendMessage()
{
  uint8_t radioBufLen = 0;
 
  // Prepare the Message headers
  myMsg.src = nodeAddr;
  myMsg.dst = baseAddr;
 
  // Encode Message and get the full length
  myMsg.getSerializedMessage(radioBuf, &radioBufLen);
 
  // Send it
  myRadio.send(radioBuf, radioBufLen);
  myRadio.waitPacketSent(100);
  myRadio.sleep();
 
}
#4