JDY-31 SPP-C Bluetooth 2.0 Serial Pass-Through Module

Connect the module's UART TX/RX pins to a USB-to-serial adapter or microcontroller serial port. Power it with 3.3V, set your terminal software to the default baud rate (typically 9600 or 115200), and send AT commands like AT+NAME to change the Bluetooth device name or AT+BAUD to adjust the communication speed. Refer to the module's specific datasheet for the complete AT command set and proper wiring connections.

Connect the JDY-31's VCC pin to the Arduino's 3.3V output, GND to GND, TXD to the Arduino's RX pin (e.g., digital pin 0), and RXD to the Arduino's TX pin (e.g., digital pin 1). Ensure you use a logic level converter if your Arduino operates at 5V, as the module's maximum voltage is 3.6V. For software serial, assign any other digital pins and initialize the SoftwareSerial library accordingly in your sketch.

Yes, the JDY-31 using Bluetooth 2.0 is generally backward compatible and should pair with most Android or iOS devices. You will need a serial terminal app on your phone (like Bluetooth Terminal) to establish communication. Note that Bluetooth 2.0 offers lower data rates and potentially less stable connections compared to newer BLE 4.0/5.0 modules, which might be preferable for new designs requiring higher performance or lower power.