Choosing a Microcontroller

A project log for Always On, Low Power Digital Assistant

An always-on digital assistant that fits on a desk/nightstand/mirror/wall/fridge. Weather, alarm, timer, calendar, habit tracker, to-do list

Darian JohnsonDarian Johnson 05/19/2021 at 02:380 Comments

Using an ESP device was a no-brainer for my design, as the ESP family of microcontrollers come with wifi (without a secondary chip). 

An ESP8266 wasn't an option, given the lack of pins and the security gaps. So, that left me with the ESP32 and the ESP32-S2. Both have plenty of IO and operate at low power. Cost is roughly the same as well.

I ultimately decided on the ESP32-S2 for a few reasons:

  1. Native USB - which means no USB to Serial chip is needed for programing
  2. Ability to run Circuit Python (checking another box in the "hacker friendly" category)
  3. Lower power consumption during wake and wifi usage
  4. Slightly lower cost

Running BOM (@250 units)

ComponentFunctionDeep Sleep (uA)Costs (USD)
Sharp Memory Display (LS027B7DH01A)Display10-35$20.00
ESP32-S2 WROVERuC20$2.40