I don’t currently own any xiao boards but have extensively used esp32 chip boards of various flavors primarily running tasmota in which I write drivers in their tamosta berry language. That’s pretty versatile and avoids compiling/writing C, but I have a specific project in mind
My project needs a battery operated low power temperature sensor (using e.g. a xiao) and I need to send its values to an esp32 (e.g. another xiao) of some flavor for controlling a heating device.
So reading the wiki i’d say I could use a XIAO nRF52840 for my battery powered temperature sensor along with a SHT41
I’d code it to wake it up every minute or two, take a reading, transmit (via bluetooth) it to the “base” (e.g. another xiao) and go back to sleep. If I read the literature the xiao takes about 5uA in sleep. I can unpower the SHT41 during that sleep so it’s effectively zero. Not sure though what the current draw will be to read the sht41 and transmit the values, nor how long that might take. If say it’s 500uA for 2 seconds then a 400mAh battery would last way more than year. This sensor will likely be in the same room or adjacent hallway so I don’t need long distance transmission, i.e. bluetooth should be work fine.
https://www.allaboutcircuits.com/tools/battery-lifetime-calculator/
At the receiving end the esp will not only control a heater but needs to act as a gateway to the wifi and/or interface for BLE phone app. I read that an esp32 that has both wifi/bluetooth capability can’t run those at the same time but if you have two cores you can assign the wifi on one and bluetooth on the other. Thus it looks like the xiao S3 or C6 would work for the “base” controller. I assume the bluetooth can pair to both the temperature XIAO and a phone at the same time.
So can folks comment on viability of usings XIAOs as I described above and including pitfalls. Has anyone actually done xiao xiao bluetooth project, and or set up a XIAO nRF52840 as a low power battery powered sensor transmitter.