Small board for battery powered project

[Minyiky]

Hi all,

I have a project in mind (a handheld / wearable device) that ideally wants as small a board as possible while also mainting the ability to go into long periods of deep sleep on battery power. I will have a display and several snesors attached to it. So far I have been using an firebeetle ESP32 and really enjoying it but smaller than that would be ideal. So far I have tried to do some research but have not managed to make much prgress in some areas.

What I am looking at:

esp32 (Tiny pico nano - https://www.tinypico.com/tinypico-nano) - This board would be familiar to me in the sense that I have worked with an esp32 device before. It also seems to have slightly more gpios broken out than the firebeetle which is a positive. This has about the size footprint I would be looking for, and if no other better options present themselves will likely be what I go for.

nrf52840 - This looks like it will offer an opportunity for very low powers and I have found a couple of boards with a small footprint such as this https://makerdiary.com/products/nrf52840-m2-module.

stm32L4(+) - This chip looks like the best option from what I have found, the ability to control a MIPI DSI display could be very beneficial. It is however the chip where I have found the least options in terms of development boards that are small.

If anyone has any particular knowledge of any boards I have missed, or any personal experiences about the capabilities of each chip I would greatly appreciate it.

Thanks for the help

[jimmo]

I have a project in mind (a handheld / wearable device) that ideally wants as small a board as possible while also mainting the ability to go into long periods of deep sleep on battery power.

What does your device require for connectivity? The three chips you suggested vary significantly:
- esp32 : has wifi, bluetooth classic, bluetooth low energy but doesn't have usb
- nrf52 : has bluetooth low energy and usb
- stm32l4 : has usb

The stm32wb55 might be worth looking at too (has BLE and USB). The dev kit comes with boht a nucleo board and a (relatively small) usbdongle board. MicroPython supports the BLE on this chip (and USB like all STM32 families).

In general, MicroPython support is better on STM32, followed by ESP32, then nRF.

[Minyiky]

Hi there,

Thank you for your answer, for connectivity I would really want Bluetooth, I am not too worried about USB connectivity.

I hadn't realised that the stm32l4+ series didn't have Bluetooth inbuilt which would be a bit of a pain and so it looks like sticking with the esp32 may be the best option but I will have a look into the board you mentioned.