How to Use 12V Single Button Bistable Self-Locking Relay Module One-button Push to Start and Stop Self-locking Relay Module: Examples, Pinouts, and Specs

The 12V Single Button Bistable Self-Locking Relay Module by Hailege is a versatile electronic component designed for controlling high-voltage devices using a low-voltage signal. This module features a single push-button that toggles the relay state between ON and OFF, with a self-locking mechanism that retains the last state even after power loss. Its compact design and ease of use make it ideal for applications requiring simple on/off control.

• Home automation systems (e.g., controlling lights, fans, or appliances)
• Industrial equipment control
• DIY electronics projects
• Automotive systems for toggling devices like lights or pumps
• Arduino and microcontroller-based projects

Below are the key technical details of the module:

The module has a simple pinout for easy integration into circuits:

1. Power the Module: Connect the VCC pin to a 12V DC power supply and the GND pin to ground.
2. Connect the Load:
   • For devices that should be powered when the relay is ON, connect the load between the NO (Normally Open) and COM (Common) terminals.
   • For devices that should be powered when the relay is OFF, connect the load between the NC (Normally Closed) and COM terminals.
3. Toggle the Relay: Press the onboard button to toggle the relay state between ON and OFF. The relay will maintain its state until the button is pressed again.
4. Indicator LEDs: Observe the onboard LEDs:
   • Power LED indicates the module is powered.
   • Relay state LED indicates whether the relay is ON or OFF.

• Ensure the load connected to the relay does not exceed the maximum voltage (250V AC / 30V DC) or current (10A) ratings.
• Use proper insulation and safety precautions when working with high-voltage devices.
• If integrating with a microcontroller (e.g., Arduino), use an external transistor or optocoupler to trigger the relay safely.

To control the relay module using an Arduino UNO, you can replace the onboard button with a digital signal from the Arduino. Below is an example code snippet:

// Define the pin connected to the relay module
const int relayPin = 7; // Connect Arduino pin 7 to the relay module's button input

// Variable to track the relay state
bool relayState = false;

void setup() {
  pinMode(relayPin, OUTPUT); // Set the relay pin as an output
  digitalWrite(relayPin, LOW); // Initialize the relay in the OFF state
}

void loop() {
  // Simulate a button press to toggle the relay state
  relayState = !relayState; // Toggle the relay state
  digitalWrite(relayPin, relayState ? HIGH : LOW); // Update the relay state
  
  delay(1000); // Wait for 1 second before toggling again
}

Note: The onboard button must be removed or bypassed when controlling the relay with an Arduino.

1. Relay Does Not Toggle:

   • Ensure the module is powered with a stable 12V DC supply.
   • Check the onboard button or the control signal from the microcontroller.
   • Verify the load does not exceed the relay's maximum ratings.

2. Relay Stays in One State:

   • Confirm the button or control signal is functioning correctly.
   • Inspect the relay module for physical damage or loose connections.

3. Load Does Not Operate:

   • Check the wiring between the relay terminals and the load.
   • Ensure the load is functional and within the relay's voltage/current limits.

Q: Can the module retain its state after a power outage?
A: Yes, the bistable relay design ensures the module retains its last state even after power is restored.

Q: Can I use this module with a 5V microcontroller?
A: Yes, but you will need a transistor or optocoupler to safely interface the 5V signal with the 12V relay module.

Q: Is the module suitable for AC loads?
A: Yes, the relay can handle AC loads up to 250V and 10A. Ensure proper insulation and safety precautions.

Q: Can I use this module for rapid switching?
A: No, the relay is not designed for high-frequency switching. Use a solid-state relay for such applications.