#include <SPI.h>
#include <MySensor.h>
#define round(x) ((x)>=0?(long)((x)+0.5):(long)((x)-0.5))
#define CHILD_ID_BATTERY 0
#define SLEEP_TIME 600000 // Sleep time between reads (in milliseconds)
#define STABILIZATION_TIME 500 // Let the sensor stabilize 0.5 seconds before reading
#define BATTERY_FULL 3000 // 3,000 millivolts when battery is full (assuming 2xAA)
#define BATTERY_ZERO 1700 // 1,700 millivolts when battery is empty (reqires blown brownout detection fuse, use 2,800 otherwise)
// This sketch assumes power from 2xAA on Vcc (not RAW). Remove the power led and the voltage regulator for better battery life.
// Sensors shall be connected to GND and their analog pin. Throw away the middle chip, just use the pitchfork.
// Number of analog pins for each Arduino model can be seen at
https://www.arduino.cc/en/Products/Compare
// A5 and A6 on most Arduinos cannot be used because they don't have internal pullups
const int SENSORS[] = {A0, A1, A2, A3}; // Remove the pins that you don't want to use
#define N_ELEMENTS(array) (sizeof(array)/sizeof((array)[0]))
long oldvoltage = 0;
MySensor gw;
MyMessage moisture_messages[N_ELEMENTS(SENSORS)];
MyMessage voltage_msg(CHILD_ID_BATTERY, V_VOLTAGE);
void setup()
{
gw.begin();
gw.sendSketchInfo("Plants moisture w bat", "1.2");
gw.present(CHILD_ID_BATTERY, S_CUSTOM);
for (int sensor = 0; sensor < N_ELEMENTS(SENSORS); sensor++) {
moisture_messages[sensor].sensor = sensor + 1; // Battery uses child ID 0 so sensors start at 1
moisture_messages[sensor].type = V_HUM;
delay(250);
gw.present(sensor + 1, S_HUM);
}
for (int i = 0; i < N_ELEMENTS(SENSORS); i++) {
pinMode(SENSORS
, OUTPUT);
digitalWrite(SENSORS, LOW);
}
}
void loop()
{
for (int sensor = 0; sensor < N_ELEMENTS(SENSORS); sensor++) {
pinMode(SENSORS[sensor], INPUT_PULLUP); // "Power on" the sensor and activate the internal pullup resistor
analogRead(SENSORS[sensor]); // Read once to let the ADC capacitor start charging
gw.sleep(STABILIZATION_TIME);
int moistureLevel = (1023 - analogRead(SENSORS[sensor])) / 10.23;
// Turn off the sensor to conserve battery and minimize corrosion
pinMode(SENSORS[sensor], OUTPUT);
digitalWrite(SENSORS[sensor], LOW);
gw.send(moisture_messages[sensor].set(moistureLevel));
}
long voltage = readVcc();
if (oldvoltage != voltage) { // Only send battery information if voltage has changed, to conserve battery.
gw.send(voltage_msg.set(voltage / 1000.0, 3)); // redVcc returns millivolts and set wants volts and how many decimals (3 in our case)
gw.sendBatteryLevel(round((voltage - BATTERY_ZERO) * 100.0 / (BATTERY_FULL - BATTERY_ZERO)));
oldvoltage = voltage;
}
gw.sleep(SLEEP_TIME);
}
long readVcc()
{
// From http://provideyourown.com/2012/secret-a ... y-voltage/
// 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__)
ADMUX = _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
}