RF WiFi Bridge

This project aims to design a simple RF-Wifi-Bridge mainly to receive RF (433 MHz) sensor data from inexpensive battery supplied sensors.

Nevertheless, it offers a RF transmitter, too.

Also it should be a replacement for Sonoff's RF-Bridge. RF-Bridge mostly must be hardware modified and lacks an easy way to directly install a custom firmware. Shortly, it is complicated in use.

My main goal was to receive sensor data from low cost TFA (or LaCrosse) 433 Mhz temperature and humidity sensors to use the data with ESPHOME and Home Assistant. The companion repository rf-sensor-bridge (previous tfagateway) provides the open source code base to receive data from such sensors.

The main features of RF-Wifi-Bridge

• Build in 433 MHz Antennas.
• More processing power than RF-Bridge. You can either use an inexpensive ESP32-C3 supermini or use Seeed Studio Xiao modules. It was tested with a Xiao ESP32-S3 module.
• Option to assemble alternative RF receiver modules, either RXB6 or RXB12 or a small SYN480R based module . Some people claimed to get the best results with RXB6 modules, but I prefer the small SYN480R based module.
• Up from Version 4.0.0 CC1101 based tranceiver modules are supported as alternative assembly for receiver and transmitter.
• Option to assemble a SYN115 based module for transmission.
• Low-noise power supply for the RF modules using an analog low-dropout regulator.
• Feed-through for mounting the external antenna used with Xiao modules on the bottom of the case.
• Designed for a standard off-the-shelf housing from BOX4u.

Miscellaneous

• PIN 1 (GPIO05 with the ESP32-C3 supermini) transmits bit stream data to the SYN115 module
• PIN 6 of the module (GPIO10 with the ESP32-C3 supermini) brightens a LED when the pin is pulled to low.
• PIN 13 (GPIO04 with the ESP32-C3 supermini) receives bit stream data from one of the RF receive modules.
• Please consider docs/pin-assignment.ods for more information how to configure the GPIOs of your ESP32 hardware.
• Power supplied from USB via the used ESP32 module.
• The microcontroller module is directly soldered to the PCB without headers.
• The Xiao modules provide less terminals than then ESP32-C3 supermini modules. Please mount the modules aligned to the PCB's edge.

CC1101 module from Ebyte

With the module from Ebyte you can use the provided PCB-antenna or the antenna assembled with your module. Unfortunately, if using the PCB-Antenna you have to remove the previous antenna from the module and connect the antenna trace to the PCB-antenna via the provided drillhole. If you like to fasten the CC1101 module with screws you must take plastic screws and nuts.

License

Please consider LICENSE.txt

Emphasis

This project wouldn't be possible without KiCad . KiCad is a great tool.

Some impressions

Layouts of Revisions

Revision 2.1 with a SYN480R module assembled

Housing with a RXB6 module assembled

Xiao ESP32-S3 with external antenna. Please consider the different mounting compared to ESP32-C3 Supermini modules.

SYN115 Module for transmission

CC1101 module as alternative trancever

(c) 2026 KHit6