Reed Switch

// Pin number: change this to match your wiring
#define REED_PIN 2   // Arduino digital pin connected to SIGNAL (e.g. D2)
#define LED_PIN 13   // LED pin (Arduino built-in LED on pin 13, or external LED)

void setup() {
  // Initialize pin modes
  pinMode(REED_PIN, INPUT);   // Set magnetic switch pin as input (to read detection state)
  pinMode(LED_PIN, OUTPUT);   // Set LED pin as output (to control LED on/off)
  
  // Start serial for debugging (9600 baud)
  Serial.begin(9600);
  
  Serial.println("Magnetic switch program started");
  Serial.println("LED on when magnetic field detected, LED off when no magnetic field");
}

void loop() {
  // Read magnetic switch state
  int reedState = digitalRead(REED_PIN);  // Read switch pin level: HIGH(1) = magnetic field detected, LOW(0) = no magnetic field
  
  // Control LED based on detection state
  if (reedState == HIGH) {
    // Magnetic field detected: LED on
    digitalWrite(LED_PIN, HIGH);
    Serial.println("Magnetic field detected - LED on");
  } else {
    // No magnetic field detected: LED off
    digitalWrite(LED_PIN, LOW);
    Serial.println("No magnetic field detected - LED off");
  }
  
  delay(100);  // Brief delay to avoid reading too fast
}

# Import required modules
from machine import Pin  # GPIO control
import time              # For delay (time.sleep)

# Pin number: change these to match your wiring
REED_PIN = 0    # GPIO connected to SIGNAL (e.g. GPIO 0)
LED_PIN = 1     # LED pin (GPIO 1, or external LED, Pico built-in LED is GPIO 25)

# Create pin objects
reed = Pin(REED_PIN, Pin.IN)   # Set magnetic switch pin as input (to read detection state)
led = Pin(LED_PIN, Pin.OUT)    # Set LED pin as output (to control LED on/off)

print("Magnetic switch program started")
print("LED on when magnetic field detected, LED off when no magnetic field")

# Main loop: runs forever
while True:
    # Read magnetic switch state
    reedState = reed.value()   # Read switch pin level: 1 = magnetic field detected (HIGH), 0 = no magnetic field (LOW)
    
    # Control LED based on detection state
    if reedState == 1:
        # Magnetic field detected: turn LED on and print message
        led.on()                 # Output HIGH, LED on
        print("Magnetic field detected - LED on")
    else:
        # No magnetic field detected: turn LED off
        led.off()                # Output LOW, LED off
        print("No magnetic field detected - LED off")
    
    # Delay 100 milliseconds to avoid reading too fast
    time.sleep_ms(100)