The JDY-40 has several pins. For this best example (transparent serial), we only need a few: JDY-40 Pin Arduino Connection 3.3V3.3 cap V 3.3V3.3 cap V GND RXD UART Receive Pin 3 (Software Serial TX) TXD UART Transmit Pin 2 (Software Serial RX) SET Mode Setting Floating (Running Mode) / GND (AT Command) CS Chip Select Floating (Active) / GND (Sleep)
// Basic JDY-40 Configuration // Connect JDY-40 SET pin to Arduino Pin 3
| Mode | Description | | :--- | :--- | | A0 | Use for general data transfer. | | C0/C1 | Remote Control Transmitter. Sends key press status from GPIO pins. | | C2 | Remote Control Receiver. GPIO goes high for 30ms when a signal is received. | | C3 | Remote Control Receiver. GPIO goes low for 30ms when a signal is received. | | C4 | Remote Control Receiver. GPIO acts as a latch, toggling state with each signal. | | C5 | Remote Control Receiver. Inverts the GPIO level upon receiving a signal. |
If you are currently building a specific project, please let me know: What or sensor reading are you trying to send? What is your required physical operating range ? Are you using battery power or a plug-in power source? jdy40 arduino example best
Below is a robust, production-ready master-slave code workflow. The Master reads an analog sensor value (like a potentiometer) and sends it wirelessly. The Slave receives it and adjusts the brightness of an LED. The Master Code (Transmitter)
To get the best results, use the SoftwareSerial library so you can keep the hardware serial port for debugging.
To make two JDY-40 modules talk to each other, they must share the same and Device Address (DADDR) . By default, they usually pair automatically out of the box, but learning to configure them ensures your network remains secure and interference-free. The JDY-40 has several pins
Common commands:
return false; // Retry or indicate failure
A full-duplex communication bridge that allows the user to change the JDY-40 baud rate via Arduino code (removing the need for USB-to-TTL adapters for setup) and provides a "Heartbeat" signal quality indicator . Sends key press status from GPIO pins
Never send a command without an acknowledgment.
SoftwareSerial jdy(2, 3); // RX on pin 2, TX on pin 3