NodeMCU + I2C-controlled FM Transmitter + AP Mode + TRS Electret Microphone = Remote Control Listening Device
Adafruit Stereo FM Transmitter with RDS/RBDS Breakout - Si4713 https://www.adafruit.com/product/1958
You must also download this tool to the Arduino IDE: https://github.com/esp8266/arduino-esp8266fs-plugin
This will allow you to upload the .HTML, and .CSS files
You will also need these two libraries:
https://github.com/me-no-dev/ESPAsyncTCP
https://github.com/me-no-dev/ESPAsyncWebServer
- Solder length of wire for antenna
- Wire up Si4713 breakout board to NodeMCU. Audio device must be transmitting at line level, mic level audio sources will not work.
| Node | Si4713 |
|---|---|
| 3V | VIN |
| GND | GND |
| D1 | SDA |
| D2 | SCL |
| D6 | RST |
- Connect TRS electret mic to Si4714 TRS jack
- Upload firmware
- Connect to "hackerradio" AP broadcast by NodeMCU
- Open browser, navigate to 192.168.4.1
- Enter a frequency and click submit (For example 102.35MHz should be entered as 10235)
- Tune FM radio to same frequency
- Talk and listen
Example of the HTTP POST request: http://192.168.4.1/changefrequency?newfrequency=10230
- You must edit the Adafruit_Si4713.cpp file to work with NodeMCU
- Add a new line to: bool Adafruit_Si4713::begin(uint8_t addr, TwoWire *theWire)
...
_wire = theWire;
_wire->pins(4,5); //ADD THIS LINE ONLY WHEN USING A NodeMCU <===================
_wire->begin();
...
BOM
https://partsbox.com/mbparks/project/22hpb7c3a4jxg8dhe0753b87zm/bom