How long should a 4-pack of 1,5V AA batteries last?


I am using a board with ATmega328P+ESP8266 chips on it for some basic moisture sensor measurement. The ATmega part checks two moisture sensors (connected to 5V and 3.3V pins on the board), sends the data over the serial bus to the ESP and goes to sleep for 8 seconds. The ESP reads the data, sends a POST request to my RPi and goes to deep sleep for 20 seconds.

I have bought a plastic 4-pack housing AA batteries to power it, however it only lasted about 12 hours approximately.

My question is - is this battery life expected from a project like this or have I done something wrong? Sorry if it is a dumb question, it is my first project.

Thank you for your answers

Have you measured the current consumption of your project ?

I have not since I forgot to buy such equipment when ordering the stuff. Thats why I want to ask if there is anything conceptually wrong with the way I have done it. I will get something to measure it the next time I order something.

how do you power the moisture sensor?

ATmega328P+ESP8266 chips on it

do you have a link? on some boards you'll eat up current just because they have leds all over the place or a poor regulator... How you power the board is important too

Arduino Uno+WiFi ATmega328P+ESP8266 32Mb | LaskaKit a bad one, just wanted a board that I can try stuff on and buy something better in the future in case I am interested

I power both of the moisture sensors by using a 5V and 3.3V pins onthe board

those types of boards are indeed sucking in lots of power (regulators etc)

I power both of the moisture sensors by using a 5V and 3.3V pins onthe board

so they stay constantly powered, even when you sleep --> they draw current too

thanks for the tip, though I am not sure on how to address this - apparently you cannot turn off power pins, but digital pins could be used to power some small stuff, although I cannot find how much they draw

you could drive through the Digital pins if the current draw is OK (so read the spec of what you connect) or need some external circuit (transistor for example) so that you could turn on or off the external device's power

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seems to be working for my usecase, thank you very much :slight_smile:

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