Best — Jdy40 Arduino Example

The JDY-40 runs at 3.3V. While many users connect the TX pin directly to an Arduino’s RX (5V tolerant), you should never connect the JDY-40’s RX directly to an Arduino’s TX (5V) without a voltage divider. I recommend using a simple resistor divider (2x 10kΩ resistors) or a level shifter.

JDY-040/JDY-041 module. JDY-040 module Serial Wireless transceiver info. PLEASE NOTE: this module is 3v3 limited - don't apply 5v. jdy40 arduino example best

| Feature | JDY-40 | nRF24L01+ | HC-12 (433MHz) | | :--- | :--- | :--- | :--- | | | UART (Easy) | SPI (Complex Library) | UART (Easy) | | Max Range | 120m+ | 100m (with PA/LNA) | 1000m+ | | Frequency | 2.4 GHz | 2.4 GHz | 433 MHz | | Max Baud Rate | 19200 | 2 Mbps | 115200 | | Sleep Current | ~5uA | ~900nA | ~16mA | | Best Use Case | Simple wireless, remote control | High-speed data, complex networks | Long-range, outdoor, low-interference | The JDY-40 runs at 3

What the example typically includes (practical checklist) JDY-040/JDY-041 module

Every JDY-40 module ships with identical default parameters ( RFID: 1024 , DVID: 2453 ). If multiple projects are running in the same vicinity, cross-communication will occur. Always rewrite these values via AT commands to unique combinations for your specific application network.

Because the JDY-40 operates strictly at 3.3V, connecting it directly to a 5V Arduino Uno or Nano requires care. While the TX pin of the JDY-40 can safely trigger a 5V Arduino RX pin, the Arduino's 5V TX pin can damage the JDY-40 RX pin over time. A logic level converter or a simple resistor voltage divider is highly recommended for the RXD line. Wiring Connections JDY-40 Pin Arduino Uno / Nano Pin Ensure your Arduino can supply enough current. GND Common ground is mandatory. TXD Pin 2 (Software RX) Direct connection. RXD Pin 3 (Software TX) Via Voltage Divider (1kΩ and 2kΩ resistors). SET Digital pin used to toggle between AT Mode and Data Mode. CS Tied to ground to keep the module constantly awake. Designing the Voltage Divider for RXD To safely step down the Arduino’s 5V signal to 3.3V: Connect Arduino Pin 3 to a 1kΩ resistor .