Connecting FL-3FF-SZ 12V Relay to Arduino

The FL-3FF-SZ is a 12V relay module that can be easily interfaced with Arduino for controlling high-voltage devices. This guide will walk you through the process of connecting and using this relay with an Arduino board.

Components Needed

  1. Arduino board (e.g., Arduino Uno)
  2. FL-3FF-SZ 12V Relay module
  3. Jumper wires
  4. Breadboard (optional)
  5. 12V power supply for the relay (if not using Arduino’s 5V output)

Relay Specifications

The FL-3FF-SZ 12V relay has the following specifications:

  • Operating voltage: 12V DC
  • Trigger voltage: 5V DC (compatible with Arduino’s digital output)
  • Contact rating: 10A 250VAC / 10A 30VDC
  • Pins: VCC, GND, IN (Signal)

Connecting the Relay

  1. Power the relay:

    • Connect the VCC pin of the relay to the 5V pin on the Arduino
    • Connect the GND pin of the relay to the GND pin on the Arduino

  2. Control signal:

    • Connect the IN pin of the relay to a digital pin on the Arduino (e.g., pin 7)

Arduino Code

Here’s a simple Arduino sketch to demonstrate controlling the relay:

const int relayPin = 7;  // Digital pin connected to the relay's IN pin

void setup() {
  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, LOW);  // Ensure relay starts in OFF state
}

void loop() {
  digitalWrite(relayPin, HIGH);  // Turn relay ON
  delay(2000);                   // Wait for 2 seconds
  digitalWrite(relayPin, LOW);   // Turn relay OFF
  delay(2000);                   // Wait for 2 seconds
}

Using the Relay

  1. Connecting a load:

    • Connect your load (e.g., a lamp) to the COM (Common) and NO (Normally Open) terminals of the relay
    • Ensure the load’s power supply is appropriate for the relay’s rating

  2. Safety considerations:

    • Always disconnect the power source before making connections
    • Use appropriate insulation and enclosures when working with high voltage
    • Consult an electrician if you’re unsure about high-voltage connections

Troubleshooting

  • If the relay doesn’t switch, check all connections and ensure the Arduino is properly powered
  • Verify that the control signal from the Arduino is reaching the relay’s IN pin
  • Make sure the relay’s power supply is adequate (5V from Arduino or external 12V source)

Remember, safety first when working with relays and high-voltage circuits!