ESP32 Forum

Hello. I am working on a project that requires connecting to MQTT client, sending some data and then going to sleep.

The form factor of the device should be as small as possible but the requirement #1 is ultra low power.

I have been doing some research but could not find concrete answer on which ESP32 module/chip is most suitable for ultra low power applications.

I have been looking at:

ESP-WROOM-32
ESP32-PICO-D4
ESP32-C2

Check the section "current consumption" in the datasheets of the SoCs or modules you're interested in.

If all you need is basically WiFi+MQTT, then the -C2 may be the lowest power option to get the job done. Definitely prefer a single-core model over a dual-core.

Note however that (WiFi) RF consumes much more energy than the rest of the chip combined. (For the -C2 (datasheet): CPU+peripherals ~15mA, WiFi RF ~50-350mA) The power required for WiFi RF is pretty consistent across the ESPs, so you may want to take into account that any power savings in the "core" may hardly make a difference if WiFi needs to be active whenever the chip is not sleeping.