R04B 433MHz Wireless Receiver Module

Connect the module's VCC and GND pins to your board's 3.3V or 5V and ground. The four output pins (A, B, C, D) provide CMOS-level logic signals. Connect these to digital input pins on your microcontroller. When a corresponding button on a paired 433MHz remote is pressed, the respective output pin will go high. You can read these pins using digitalRead() in Arduino IDE to trigger actions like turning on an LED or relay. Ensure you use a common ground between the module and your controller.

These modes define the behavior of the output signal after a remote button press. Inching mode provides a momentary pulse; the output goes high only while the button is held. Self-locking mode toggles the output state with each button press, latching it on or off. Interlocking mode ensures only one output channel is active at a time; pressing a new button deactivates the previous channel. The specific mode is typically determined by the internal circuitry of the module and may be fixed or configurable via jumpers, depending on the manufacturer's design.

For optimal performance at 433MHz, use a quarter-wave monopole antenna approximately 17.3cm (6.8 inches) long. You can solder a simple straight wire to the antenna pad on the module. Ensure the antenna is kept straight and away from large metal objects or other electronics to minimize interference. For a more robust setup, a flexible whip antenna with an SMA connector can be used if your module variant includes a connector. Proper antenna placement and impedance matching are critical to achieving the advertised receiving distance of over 45 meters.