Controlling several MCUs wirelessly (ESP-Now)

Description

While constructing the “Clock made with “24 clocks”” I noticed the EMI problems. I was wondering how to control the 4 digits separately without redesigning the PCBs. Thus, the idea to use a wireless solution.

Project summary

In this project I tried to wirelessly control 4 MCUs with one separate master.

My responsibilities

• Programming and testing

Results

Like usually the basic SW examples were working fast and without hassle. Trying to implement it with my preexisting solution required some additional effort. Nevertheless, I was able to implement two way communications - the master sends command to all 4 slaves and waits for the answer. Only if the answer has been received next commands could be executed. 

Overall the ESP Now protocol is very fast and simple to use. The only downside is that the master cannot be connected at the same time to Wifi. Thus, for a clock application there must be an additional board that is connected to the Wifi for accurate clock updates.

To sum up, I was able to implement what was intended and one could use the protocol for some other projects.

Used tools

SW: Arduino IDE

HW: ESP32