BatteryPoweredSensor.ino

/*
 * 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 <[email protected]>
 * Copyright (C) 2013-2019 Sensnology AB
 * Full contributor list: https://github.com/mysensors/MySensors/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.
 *
 *******************************
 *
 * DESCRIPTION
 *
 * This is an example that demonstrates how to report the battery level for a sensor
 * Instructions for measuring battery capacity on A0 are available here:
 * http://www.mysensors.org/build/battery
 *
 */
 
 
 
// Enable debug prints to serial monitor
#define MY_DEBUG
 
// Enable and select radio type attached
#define MY_RADIO_RF24
//#define MY_RADIO_NRF5_ESB
//#define MY_RADIO_RFM69
//#define MY_RADIO_RFM95
 
#include <MySensors.h>
 
int BATTERY_SENSE_PIN = A0;  // select the input pin for the battery sense point
 
uint32_t SLEEP_TIME = 900000;  // sleep time between reads (seconds * 1000 milliseconds)
int oldBatteryPcnt = 0;
 
void setup()
{
    // use the 1.1 V internal reference
#if defined(__AVR_ATmega2560__)
    analogReference(INTERNAL1V1);
#else
    analogReference(INTERNAL);
#endif
}
 
void presentation()
{
    // Send the sketch version information to the gateway and Controller
    sendSketchInfo("Battery Meter", "1.0");
}
 
void loop()
{
    // get the battery Voltage
    int sensorValue = analogRead(BATTERY_SENSE_PIN);
#ifdef MY_DEBUG
    Serial.println(sensorValue);
#endif
 
    // 1M, 470K 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
    // ((1e6+470e3)/470e3)*1.1 = Vmax = 3.44 Volts
    // 3.44/1023 = Volts per bit = 0.003363075
 
    int batteryPcnt = sensorValue / 10;
 
#ifdef MY_DEBUG
    float batteryV  = sensorValue * 0.003363075;
    Serial.print("Battery Voltage: ");
    Serial.print(batteryV);
    Serial.println(" V");
 
    Serial.print("Battery percent: ");
    Serial.print(batteryPcnt);
    Serial.println(" %");
#endif
 
    if (oldBatteryPcnt != batteryPcnt) {
        // Power up radio after sleep
        sendBatteryLevel(batteryPcnt);
        oldBatteryPcnt = batteryPcnt;
    }
    sleep(SLEEP_TIME);
}