Skip to content

Instantly share code, notes, and snippets.

Created Jun 14, 2017
What would you like to do?
// Enable debug prints
#define MY_DEBUG
// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69
//#define MY_RS485
#include <SPI.h>
#include <MySensors.h>
#include <DHT.h>
#include <Wire.h>
#include <BH1750.h>
BH1750 lightSensor;
int BATTERY_SENSE_PIN = A0; // select the input pin for the battery sense point
int oldBatteryPcnt = 0;
// Set this to the pin you connected the DHT's data pin to
#define DHT_DATA_PIN 3
// Set this offset if the sensor has a permanent small offset to the real temperatures
// Sleep time between sensor updates (in milliseconds)
// Must be >1000ms for DHT22 and >2000ms for DHT11
static const uint64_t UPDATE_INTERVAL = 30000;
// Force sending an update of the temperature after n sensor reads, so a controller showing the
// timestamp of the last update doesn't show something like 3 hours in the unlikely case, that
// the value didn't change since;
// i.e. the sensor would force sending an update every UPDATE_INTERVAL*FORCE_UPDATE_N_READS [ms]
static const uint8_t FORCE_UPDATE_N_READS = 10;
#define CHILD_ID_HUM 0
#define CHILD_ID_TEMP 1
#define CHILD_ID_VOLT 3
#define CHILD_ID_LIGHT 5
// Disable repeater for now
float lastTemp;
float lastHum;
uint8_t nNoUpdatesTemp;
uint8_t nNoUpdatesHum;
uint8_t nNoUpdatesLux;
uint8_t nNoUpdatesBattP;
uint8_t nNoUpdatesBattV;
bool metric = true;
unsigned long Timer = 0;
const long IntervalReadSensor = 12000.;
const long IntervalReadBatt = 30000;
unsigned long TimerBatt = 0;
MyMessage msgHum(CHILD_ID_HUM, V_HUM);
MyMessage msgTemp(CHILD_ID_TEMP, V_TEMP);
MyMessage msgVolt(CHILD_ID_VOLT, V_VOLTAGE);
MyMessage msgLux(CHILD_ID_LIGHT, V_LEVEL);
uint16_t lastlux;
float lastvolt;
DHT dht;
void presentation()
// Send the sketch version information to the gateway
sendSketchInfo("Temp en vocht tuin", "2.1");
// Register all sensors to gw (they will be created as child devices)
present(CHILD_ID_HUM, S_HUM);
metric = getControllerConfig().isMetric;
void setup()
// use the 1.1 V internal reference
#if defined(__AVR_ATmega2560__)
// Low Power mode
dht.setup(DHT_DATA_PIN); // set data pin of DHT sensor
if (UPDATE_INTERVAL <= dht.getMinimumSamplingPeriod()) {
Serial.println("Warning: UPDATE_INTERVAL is smaller than supported by the sensor!");
// Sleep for the time of the minimum sampling period to give the sensor time to power up
// (otherwise, timeout errors might occure for the first reading)
void loop()
// Force reading sensor, so it works also after sleep()
int sensorValue = analogRead(BATTERY_SENSE_PIN);
// 1M, 300K 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)/300e3)*1.1 = Vmax = 4.7 Volts
// 4.7/1023 = Volts per bit = 0.00459433
int batteryPcnt = sensorValue / 10;
#ifdef MY_DEBUG
float batteryV = sensorValue * 0.00459433;
Serial.print("Battery Voltage: ");
Serial.println(" V");
Serial.print("Battery percent: ");
Serial.println(" %");
if (oldBatteryPcnt != batteryPcnt) {
// Power up radio after sleep
oldBatteryPcnt = batteryPcnt;
if (lastvolt != batteryV){
send(msgVolt.set(batteryV, 2));
lastvolt = batteryV;
delay(200); // Library says 120 ms to wait for startup, 200 just to be sure
uint16_t lux = lightSensor.readLightLevel();// Get Lux value
#ifdef MY_DEBUG
Serial.print("LUX: ");
if (lux != lastlux || nNoUpdatesLux == FORCE_UPDATE_N_READS) {
#ifdef MY_DEBUG
Serial.print("LUX: ");
lastlux = lux;
// Get temperature from DHT library
float temperature = dht.getTemperature();
if (isnan(temperature)) {
Serial.println("Failed reading temperature from DHT!");
} else if (temperature != lastTemp || nNoUpdatesTemp == FORCE_UPDATE_N_READS) {
// Only send temperature if it changed since the last measurement or if we didn't send an update for n times
lastTemp = temperature;
if (!metric) {
temperature = dht.toFahrenheit(temperature);
// Reset no updates counter
nNoUpdatesTemp = 0;
temperature += SENSOR_TEMP_OFFSET;
send(msgTemp.set(temperature, 1));
#ifdef MY_DEBUG
Serial.print("T: ");
} else {
// Increase no update counter if the temperature stayed the same
// Get humidity from DHT library
float humidity = dht.getHumidity();
if (isnan(humidity)) {
Serial.println("Failed reading humidity from DHT");
} else if (humidity != lastHum || nNoUpdatesHum == FORCE_UPDATE_N_READS) {
// Only send humidity if it changed since the last measurement or if we didn't send an update for n times
lastHum = humidity;
// Reset no updates counter
nNoUpdatesHum = 0;
send(msgHum.set(humidity, 1));
#ifdef MY_DEBUG
Serial.print("H: ");
} else {
// Increase no update counter if the humidity stayed the same
// Sleep for a while to save energy
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment