Any Ver 2.xx,
So I have cobbled together/hacked this and it seem to work, battery has stayed at 97% for 2 weeks now. Feel free to Hack about and improve i have this mounted on an easyPCB board, x2AA batteries, NRF radio, BME280 with a 3.3v convertor .
/*
* use mysensors library 2.2.0
* ALL WORKING AND TESTED ON EASY PCB BOARD WITH BATTERY SAVING CODE 29/11/18
*
* Time SET to 15 mins
* also added BME280.writeMode (smSleep); to reduce quisecent to current to 40uA
* BME280 sensor connections: 3.3v, 0V, SCL to A5, SDA to A4, BAT to A0
**/
//Enable debug prints to serial monitor
#define MY_DEBUG
// Enable and select radio type attached
#define MY_RADIO_NRF24
#define MY_RF24_PA_LEVEL RF24_PA_MIN //settings are MIN, LOW, HIGH, MAX
#define MY_NODE_ID 18
//#define MY_RADIO_RFM69
#include <SPI.h>
#include <MySensors.h>
#include <Wire.h>
#include <BME280_MOD-1022.h>
// BME280 libraries and variables
// Bosch BME280 Embedded Adventures MOD-1022 weather multi-sensor Arduino code
// Written originally by Embedded Adventures
// https://github.com/embeddedadventures/BME280
#define BARO_CHILD 0
#define TEMP_CHILD 1
#define HUM_CHILD 2
int BATTERY_SENSE_PIN = A0; // select the input pin for the battery sense point
unsigned long SLEEP_TIME = 15*60000; // sleep time between reads (seconds x*1000 milliseconds)
//unsigned long SLEEP_TIME = 20000; // Debug test time 20 seconds
int oldBatteryPcnt = 0;
long interval = 1000; // 1 min interval at which to send (milliseconds)
long previousMillis = interval; // will store last time data was sent
const float ALTITUDE = 0; // <-- adapt this value to your location's altitude (in m). Use your smartphone GPS to get an accurate value!
const char *weather[] = { "stable", "sunny", "cloudy", "unstable", "thunderstorm", "unknown" };
enum FORECAST
{
STABLE = 0, // "Stable Weather Pattern"
SUNNY = 1, // "Slowly rising Good Weather", "Clear/Sunny "
CLOUDY = 2, // "Slowly falling L-Pressure ", "Cloudy/Rain "
UNSTABLE = 3, // "Quickly rising H-Press", "Not Stable"
THUNDERSTORM = 4, // "Quickly falling L-Press", "Thunderstorm"
UNKNOWN = 5 // "Unknown (More Time needed)
};
const int LAST_SAMPLES_COUNT = 5;
float lastPressureSamples[LAST_SAMPLES_COUNT];
// this CONVERSION_FACTOR is used to convert from Pa to kPa in the forecast algorithm
// get kPa/h by dividing hPa by 10
#define CONVERSION_FACTOR (1.0/10.0)
int minuteCount = 0;
bool firstRound = true;
// average value is used in forecast algorithm.
float pressureAvg;
// average after 2 hours is used as reference value for the next iteration.
float pressureAvg2;
float dP_dt;
boolean metric;
MyMessage tempMsg(TEMP_CHILD, V_TEMP);
MyMessage humMsg(HUM_CHILD, V_HUM);
MyMessage pressureMsg(BARO_CHILD, V_PRESSURE);
float getLastPressureSamplesAverage()
{
float lastPressureSamplesAverage = 0;
for (int i = 0; i < LAST_SAMPLES_COUNT; i++)
{
lastPressureSamplesAverage += lastPressureSamples[i];
}
lastPressureSamplesAverage /= LAST_SAMPLES_COUNT;
return lastPressureSamplesAverage;
}
// Algorithm found here
// http://www.freescale.com/files/sensors/doc/app_note/AN3914.pdf
// Pressure in hPa --> forecast done by calculating kPa/h
int sample(float pressure)
{
// Calculate the average of the last n minutes.
int index = minuteCount % LAST_SAMPLES_COUNT;
lastPressureSamples[index] = pressure;
minuteCount++;
if (minuteCount > 185)
{
minuteCount = 6;
}
if (minuteCount == 5)
{
pressureAvg = getLastPressureSamplesAverage();
}
else if (minuteCount == 35)
{
float lastPressureAvg = getLastPressureSamplesAverage();
float change = (lastPressureAvg - pressureAvg) * CONVERSION_FACTOR;
if (firstRound) // first time initial 3 hour
{
dP_dt = change * 2; // note this is for t = 0.5hour
}
else
{
dP_dt = change / 1.5; // divide by 1.5 as this is the difference in time from 0 value.
}
}
else if (minuteCount == 65)
{
float lastPressureAvg = getLastPressureSamplesAverage();
float change = (lastPressureAvg - pressureAvg) * CONVERSION_FACTOR;
if (firstRound) //first time initial 3 hour
{
dP_dt = change; //note this is for t = 1 hour
}
else
{
dP_dt = change / 2; //divide by 2 as this is the difference in time from 0 value
}
}
else if (minuteCount == 95)
{
float lastPressureAvg = getLastPressureSamplesAverage();
float change = (lastPressureAvg - pressureAvg) * CONVERSION_FACTOR;
if (firstRound) // first time initial 3 hour
{
dP_dt = change / 1.5; // note this is for t = 1.5 hour
}
else
{
dP_dt = change / 2.5; // divide by 2.5 as this is the difference in time from 0 value
}
}
else if (minuteCount == 125)
{
float lastPressureAvg = getLastPressureSamplesAverage();
pressureAvg2 = lastPressureAvg; // store for later use.
float change = (lastPressureAvg - pressureAvg) * CONVERSION_FACTOR;
if (firstRound) // first time initial 3 hour
{
dP_dt = change / 2; // note this is for t = 2 hour
}
else
{
dP_dt = change / 3; // divide by 3 as this is the difference in time from 0 value
}
}
else if (minuteCount == 155)
{
float lastPressureAvg = getLastPressureSamplesAverage();
float change = (lastPressureAvg - pressureAvg) * CONVERSION_FACTOR;
if (firstRound) // first time initial 3 hour
{
dP_dt = change / 2.5; // note this is for t = 2.5 hour
}
else
{
dP_dt = change / 3.5; // divide by 3.5 as this is the difference in time from 0 value
}
}
else if (minuteCount == 185)
{
float lastPressureAvg = getLastPressureSamplesAverage();
float change = (lastPressureAvg - pressureAvg) * CONVERSION_FACTOR;
if (firstRound) // first time initial 3 hour
{
dP_dt = change / 3; // note this is for t = 3 hour
}
else
{
dP_dt = change / 4; // divide by 4 as this is the difference in time from 0 value
}
pressureAvg = pressureAvg2; // Equating the pressure at 0 to the pressure at 2 hour after 3 hours have past.
firstRound = false; // flag to let you know that this is on the past 3 hour mark. Initialized to 0 outside main loop.
}
int forecast = UNKNOWN;
if (minuteCount < 35 && firstRound) //if time is less than 35 min on the first 3 hour interval.
{
forecast = UNKNOWN;
}
else if (dP_dt < (-0.25))
{
forecast = THUNDERSTORM;
}
else if (dP_dt > 0.25)
{
forecast = UNSTABLE;
}
else if ((dP_dt > (-0.25)) && (dP_dt < (-0.05)))
{
forecast = CLOUDY;
}
else if ((dP_dt > 0.05) && (dP_dt < 0.25))
{
forecast = SUNNY;
}
else if ((dP_dt >(-0.05)) && (dP_dt < 0.05))
{
forecast = STABLE;
}
else
{
forecast = UNKNOWN;
}
return forecast;
}
void setup()
{
// use the 1.1 V internal reference
#if defined(__AVR_ATmega2560__)
analogReference(INTERNAL1V1);
#else
analogReference(INTERNAL);
#endif
metric = getControllerConfig().isMetric; // was getConfig().isMetric; before MySensors v2.1.1
Wire.begin(); // Wire.begin(sda, scl)
// 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("BME280_BAT_V2", "V2e.");
// Register sensors to gw (they will be created as child devices)
present(BARO_CHILD, S_BARO);
present(TEMP_CHILD, S_TEMP);
present(HUM_CHILD, S_HUM);
}
// Loop
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);
}
unsigned long currentMillis = millis();
if(currentMillis - previousMillis > interval) {
// save the last time sent the data
previousMillis = currentMillis;
analogReference(INTERNAL);
wait(500);
// need to read the NVM compensation parameters
BME280.readCompensationParams();
// Normal mode for regular automatic samples
BME280.writeStandbyTime(tsb_0p5ms); // tsb = 0.5ms
BME280.writeFilterCoefficient(fc_16); // IIR Filter coefficient 16
BME280.writeOversamplingPressure(os16x); // pressure x16
BME280.writeOversamplingTemperature(os8x); // temperature x8
BME280.writeOversamplingHumidity(os8x); // humidity x8
BME280.writeMode(smNormal);
// Just to be sure, wait until sensor is done mesuring
while (BME280.isMeasuring()) {
}
// Read out the data - must do this before calling the getxxxxx routines
BME280.readMeasurements();
float temperature = BME280.getTemperatureMostAccurate(); // must get temp first
float humidity = BME280.getHumidityMostAccurate();
float pressure_local = BME280.getPressureMostAccurate(); // Get pressure at current location
float pressure = pressure_local/pow((1.0 - ( ALTITUDE / 44330.0 )), 5.255); // Adjust to sea level pressure using user altitude
int forecast = sample(pressure);
if (!metric)
{
// Convert to fahrenheit
temperature = temperature * 9.0 / 5.0 + 32.0;
}
//**/
Serial.println();
Serial.print("Temperature = ");
Serial.print(temperature);
Serial.println(metric ? " °C" : " °F");
Serial.print("Humidity = ");
Serial.print(humidity);
Serial.println(" %");
Serial.print("Pressure = ");
Serial.print(pressure);
Serial.println(" hPa");
Serial.print("Forecast = ");
Serial.println(weather[forecast]);
Serial.println();
//*/
send(tempMsg.set(temperature, 1));
wait(50);
send(humMsg.set(humidity, 1));
wait(50);
send(pressureMsg.set(pressure, 2));
wait(50);
BME280.writeMode (smSleep);
sleep(SLEEP_TIME);
}
}
