R04B 315MHz Wireless Receiver Module

The R04B module operates from a DC supply voltage between 3.3V and 5V. This range makes it directly compatible with most 3.3V microcontrollers (like ESP32 or STM32) and 5V Arduino boards without requiring a level shifter. Ensure your power source is stable and can provide the required current, especially during signal reception events.

The module provides four digital output pins (typically labeled A, B, C, D) that correspond to buttons on a paired remote. These pins output a CMOS logic-level high (near VCC) or low (0V) signal when a button is pressed. Simply connect these pins to GPIO inputs on your MCU. In your firmware, configure the pins as inputs with a pull-down resistor (internal or external) and monitor their state to trigger actions.

The range depends heavily on the transmit power of the paired remote, antenna selection, and environmental obstacles. With its high -108dBm sensitivity and a decent transmitter, you can expect a reliable range of several tens of meters in open areas. For best results, use a matched 315MHz antenna (like a quarter-wave whip) on both transmitter and receiver, and ensure a clear line of sight to maximize distance.

Yes, integration is straightforward. For 5V Arduino boards (Uno, Mega), power the module from the 5V pin. For 3.3V boards like ESP32, use the 3.3V pin. Connect the module's output pins to any digital GPIO pins on the Arduino/ESP32. You will need to write a simple sketch to read the pin states. The module's low current draw is safe for the board's voltage regulator. Remember to share a common ground connection between the module and your development board.