Converting a Sonoff TX/T1/T2/T3 into a Sonoff Bridge

Inspired from

I just got some Sonoff T2 switches and noticed they have a 433MHz reciever, but none of the documentation for Esphome etc. suggested that it could be used. Most of what I found suggested there was a separate IC/circuit that handled the RF processing - so it couldn’t be made use of by Esphome.

So I dug out the datasheets for the ESP8285 chip - unfortunately, almost every GPIO pin looks to be in use - so I turned to the serial TX/RX pins - because once flashed via FTDI, Esphome can flash OTA, so they become largely redundant after this.

I gave my theory a test and soldered pin 10 on the RF chip to GPIO3 (serial RX) via a 220ohm resistor, using the following configuration in Esphome,

  pin: 3
  dump: rc_switch
  filter: 100us
  tolerance: 50%
  idle: 2ms

Low and behold, it works! The light switch is now capable of ingesting any 433MHz signal and processing it accordingly.

Now, my goal wasn’t to replace the Sonoff Bridge - its merely that I’ve got mine in use at another location and I’m waiting on another to be delivered, so I wondered if I could make use of the many light switches I have to do the same job.


1technophile has done something similar with a sonoff basic rf3