Hello,
I try to build a battery powered temperature sensor but I only found one sensor who works with low power under 2 volt. This is the bmp280 from bosch. But in i2c mode he need a power from 0,6mA so my battery life are only 2 month. Now the library from adafruit runs the sensor in normal mode and so I insert two new functions in the library:
void Adafruit_BMP280::sleep() {
write8(BMP280_REGISTER_CONTROL, 0x3C);
}
void Adafruit_BMP280::wakeup() {
write8(BMP280_REGISTER_CONTROL, 0x3F);
}
The first one write 00 to the first bits in the data register - the sleep mode.
The wakeup function rewrite the first bits with 11 - the normal mode.
void loop() {
...
...
Temp = bmp.readTemperature();
Press = bmp.readPressure() / 100.0;
Altit = bmp.readAltitude(1013.25);
bmp.sleep();
sleep(30000);
bmp.wakeup();
}
Now the sketch needs only 0,2µA in the sleep mode - it is much more better than 0,6mA.
Best regards
Elmar
