Magnetic Latching Relay Module Wiki - DFRobot

1. Introduction

The magnetic latching relay is a new type of relay developed in recent years. Unlike normal relay, the ON or OFF state of magnetic latching relay depends on the action of a permanent magnet, and the state switching is triggered by a certain width of pulse electric signal. Once set or reset, the relay remains in the current state even when powered off.
The magnetic latching relay features low power, steady performance, long service life, and low-temperature rise. It is perfect for applications requiring low power and high stability.
This DFRobot magnetic latching relay based on a special driver chip is small and easy to use, and can be used to remake home appliances or lighting controls, like smart electricity meters/lighting/sockets/switches, and so on.

2. Features

3. Applications

4. Board Overview

Num Label Description
A Trigger End A Provide the pulse with a width of more than 2ms to reverse relay state
+ Positive 3.3V-5V
- Negative
B Trigger End B Provide the pulse with a width of more than 2ms to reverse relay state
+ Positive 3.3V-5V
- Negative
A Relay Contact A
COM Relay Common end
B Relay Contact B

5. Function Overview

6. Product Dimension

Product Dimension

7. Specification

8. Tutorial

What's the purpose of this tutorial?

8.1 Requirements

8.3 Control the ON/OFF of a Water Pump

Connection Diagram

Connection 1

Connection Description

Sample Code

Press down the blue button, the water pump turns on. Press down the red button, it turns off.

int INA = 3;
int INB = 2;
int buttonA = 13; //Set Button A as blue button, connect to Pin 13 
int buttonB = 4; //Set Button B as red button, connect to Pin 4 

void setup() {
  pinMode(INA, OUTPUT);
  pinMode(INB, OUTPUT);
  pinMode(buttonA, INPUT);
  pinMode(buttonB, INPUT);
}
void loop() {
  if (digitalRead(buttonA) == HIGH) 
    {
      digitalWrite(INA, HIGH); 
      delay(2); //2ms pulse signal 
      digitalWrite(INA, LOW); 
    }
  if (digitalRead(buttonB) == HIGH) 
      digitalWrite(INB, HIGH);
      delay(2);//2ms pulse signal 
      digitalWrite(INB, LOW);
  }
}

Expected Results

When the program is downloaded, press down the blue button, the water pump turns on. Press down the red button, it turns off.

9. Notes

  1. The factory state of magnetic holding relay is reset state, but it may change to set state due to impact during transportation or installation, so please change the state to set or reset according the actual needs when using (when the power is connected).

  2. To ensure the set or reset of the magnetic holding relay, the excitation voltage applied to the coil must reach the rated voltage, and the pulse width must be greater than 4ms. the set and reset coil should not be powered simultaneously. Do not apply voltage to the coil for a long time (more than 1 minute).

  3. In the process of product transportation, storage and application, please keep the product away from the strong magnetic field to avoid the change of set and reset voltage.

FAQ

For any questions, advice or cool ideas to share, please visit the DFRobot Forum.

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