It seems that there are two competing scenarios when it comes to WiFi and Bluetooth.
1) The fastest possible speed used with web pages, etc. Can be complicated and expensive for best performance.
2) Simple non complicated safe communications for control purposes. For safe control needs to be simple and preferably low cost.
I fall into the latter category.
I have a system turning on a Remote Radiator Valve which is controlled by ONE pin on the Teensy using an ESP32C3 for communication.
The process is:
1) ESP32C3 is normally in a sleep (dormant) state.
2) Teensy asserts a pin to wake ESP32C3.
3) After 20mS Teensy maintains the pin asserted to tell ESP32C3 to turn remote valve ON, or resets the pin to tell ESP32C3 to turn remote valve OFF.
4) The ESP32C3 goes back to sleep upon completing it's task.
5) Should an error occur (Unable to communicate with remote Sonoff ESP, for example, the ESP32C3 sets an error flag and waits Uart communication from Teensy.
A Sonoff Basic WiFi relay can be had for under $5 and the ESP32C3 to interface the Teensy to WiFi and controll the Sonoff is about $2,50 (I say about because the Dollar is drifting DOWN).
So for $7.50 the Teensy is able to control (On/Off) a Mains electricity device using WiFi.
If only we had a Teensy - ESP32 library. I know
@defragster has written some code to program an ESP32 using a Teensy as a write through device.
It would be nice if we could re-program the ESP32C3 on the fly. In initial mode it would have automatic pairing capabilities, when it is paired ok, that part of the program could be "thrown away" and the main running code programmed into it.