Magnetic Door Sensor MC38 Kit (NC)

Features:

• Reliable Monitoring: Detects the opening/closing of doors and windows for real-time alerts.
• Easy Installation: Double-sided foam adhesive included for both magnetic and switching parts.
• Durable Housing: Protective plastic or metal casing ensures long-lasting performance.
• Reed Switch Technology: Ensures fast and accurate detection using magnetic fields.
• Instant Switching: Activates/deactivates within 18mm ± 6mm of magnetic proximity.
• Normally Closed (NC) Configuration: Circuit remains closed when doors/windows are shut.
• Wide Voltage Support: Rated for 12V and can withstand up to 100VDC.
• Load Current: Handles up to 300mA for compatibility with most alarm systems.

Specifications:

• Model: MC-38 NC
• Material: Plastic + Magnet
• Color: White
• Size: 27 x 14 x 7.6 mm
• Action Distance: 18mm ± 6mm
• Rated Voltage: 12V
• Withstand Voltage: 100VDC
• Load Current: 300mA

Principle of Operation:

1. When the magnet (mounted on door/window) is near the switch, the reed switch remains closed (circuit complete).
2. When the door/window opens, the magnet moves away, breaking the magnetic field and opening the circuit.
3. This change is detected by the alarm system, triggering an alert or action.

Pinout:

• 2-wire connection (no polarity): Connect either wire to the positive/negative terminal of the alarm system.

Arduino Example Code:

const int reedSwitchPin = 2;
const int ledPin = 13;
int reedSwitchState = 0;

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(reedSwitchPin, INPUT);
  Serial.begin(9600);
}

void loop() {
  reedSwitchState = digitalRead(reedSwitchPin);
  if (reedSwitchState == HIGH) {
    digitalWrite(ledPin, HIGH);
    Serial.println("Door or window closed");
  } else {
    digitalWrite(ledPin, LOW);
    Serial.println("Door or window open");
  }
  delay(500);
}

Applications:

• Home and commercial security systems
• Access control systems
• Industrial enclosures and asset protection
• Building automation for smart energy use
• Vehicle door/window detection
• IoT-connected remote monitoring systems

Circuit Diagram:

Comparison with Optical Sensors: