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kittengineering / Omgevingsmonitor_Hardware

Initial release of "de Omgevingsmonitor" as presented on the WoTS 2024
CERN Open Hardware Licence Version 2 - Weakly Reciprocal
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Reason for the STM32L072 when there is an ESP32 on board? #2

Open expaso opened 19 hours ago

expaso commented 19 hours ago

What is the reason for a separate ESP32-C3 and an STM32L072?

The ESP32 is much faster, has more flash, and more RAM. In this design, it's purely used as a WIFI chip, but will run user-code no problem, and even faster than the STM.

https://www.espressif.com/sites/default/files/documentation/esp32-c3-mini-1_datasheet_en.pdf

It looks to me that for a low-power device, you would avoid having multiple processors at work.. So..out of curiosity.. what made the design choice?

tjallingk commented 17 hours ago

i think i had nothing to do with making it. but guess its lower power to have running continuously as the esp is in sleep most the time except when sending data so its on 1% or less of the time thus using even less power and esp32 is quite a power hungry chip for solar and a small battery

expaso commented 14 hours ago

Thank you for the info!

The ESP does 5uA while in deep sleep with RTC timers enabled, and 1 uA when not enabled at all. Should be no problem.

The STM is indeed slower but consumes allmost nothing at all. According to the schematics, the STM has control over the ESPs flash functions, so I think we all know where this is heading for ..

We want this thing to run ESPHome (or at least MQTT) and connect to Home Assistant 😁.. And still run on solar power in the winter...

Totally doable! Challenge accepted 👍🏻😅

The STM is so low power, it won't make much of a difference anyway looking at the specs.