Once configured, communication becomes simple. Anything sent into the serial port of Module A instantly outputs from the serial port of Module B.
For 95% of hobbyist Arduino projects—remote thermometers, garage door openers, robot controllers, or wearable badges—the JDY-40 is arguably the module you’ve never used.
Because the JDY-40 operates on , connecting its RXD pin directly to a 5V Arduino (like the Uno or Nano) can damage the module or cause unstable behavior. Always use a logic level shifter or a simple resistor voltage divider on the Arduino's TX line. Hardware Connections: JDY-40 VCC →right arrow Arduino 3.3V JDY-40 GND →right arrow Arduino GND JDY-40 TXD →right arrow Arduino Pin 2 (Software RX) JDY-40 RXD →right arrow Through a voltage divider to Arduino Pin 3 (Software TX) Voltage divider tip: Connect Arduino Pin 3 to a 1k Ωcap omega jdy40 arduino example best
SoftwareSerial bluetooth(2, 3); // RX, TX
Connects to SoftwareSerial TX (Use a voltage divider if using 5V Arduino). Once configured, communication becomes simple
Keep the onboard PCB trace antenna clear of wires, metal chassis, and high-power components to ensure maximum range.
The JDY-40 typically breaks out into 6 or 8 pins. Here are the core pins you need for Arduino integration: Because the JDY-40 operates on , connecting its
Serial receive pin (connects to Arduino TX via a voltage divider).