The MC-38 Normally Closed Magnetic Contact Reed Switch Kit is an essential component designed for home security alarm systems, specifically to monitor doors or windows. This comprehensive kit includes a switching part and a magnetic part, both equipped with double-sided foam adhesive for effortless installation. The durable plastic or metal housing provides reliable protection for the magnet.

Package Includes:

• 1 x MC-38 Wired Magnetic Sensor kit (NC)

Features:

• Reliable Monitoring: Designed specifically for home security alarm systems, the kit provides accurate monitoring of doors or windows, ensuring prompt detection of any unauthorized access.
• Easy Installation: The kit includes a switching part and a magnetic part, both equipped with double-sided foam adhesive, allowing for effortless installation on various surfaces.
• Durable Housing: The plastic or metal housing of the kit provides reliable protection for the magnet, ensuring its longevity and performance in different environments.
• Instant Switching: When the switching and magnetic parts are within a specified distance of each other (18mm ± 6mm), the switch instantly turns on or off, providing real-time status updates.
• Reed Switch Technology: The MC-38 utilizes a reed switch, known for its sensitivity and responsiveness to magnetic fields, ensuring reliable operation and accurate detection.
• Wide Voltage Range: The switch can withstand a rated voltage of 12V, making it compatible with standard home security systems.
• High Withstand Voltage: With a switch withstand voltage of 100VDC, the MC-38 is designed to operate safely and efficiently under normal conditions.
• Load Current Capacity: The switch can handle a load current of up to 300mA, ensuring it can effectively handle the electrical demands of your security setup.
• Normally Closed Configuration: The MC-38 is designed as a normally closed (NC) switch, maintaining a closed circuit when the door or window is closed, and triggering an alert if opened.
• Versatile Application: The MC-38 Normally Closed Magnetic Contact Reed Switch Kit can be used in various settings, including homes, commercial establishments, offices, warehouses, and more, providing versatile security monitoring capabilities.

Description:

The MC-38 Normally Closed Magnetic Contact Reed Switch Kit is an essential component designed for home security alarm systems, specifically to monitor doors or windows. This comprehensive kit includes a switching part and a magnetic part, both equipped with double-sided foam adhesive for effortless installation. The durable plastic or metal housing provides reliable protection for the magnet. Operating on the principle of a reed switch, the MC-38 instantly activates or deactivates when the switching and magnetic parts come within a specified distance of each other (18mm ± 6mm). This immediate response ensures accurate detection of door or window status changes. The MC-38 switch is designed for optimal performance, withstanding a rated voltage of 12V and a switch withstand voltage of 100VDC. It can handle a load current of up to 300mA, ensuring reliable operation within standard security system requirements.

Principle of Work:

1. Components: The kit includes two main components: a switching part and a magnetic part. The switching part contains the reed switch and pigtail, while the magnetic part houses a magnet.
2. Installation: The switching part and magnetic part are typically installed on a door frame and the corresponding door itself or on a window frame and the window pane. They should be aligned in such a way that when the door or window is closed, the switching and magnetic parts are in close proximity.
3. Magnetic Field Detection: The reed switch inside the switching part is sensitive to magnetic fields. When the magnet in the magnetic part is within a specific distance (typically 18mm ± 6mm) of the reed switch, it generates a magnetic field that affects the switch.
4. Circuit Status: In the normally closed (NC) configuration, when the door or window is closed, the magnet is positioned close enough to the reed switch, causing it to remain in a closed circuit state. This means that current can flow through the switch, indicating that the door or window is closed.
5. Circuit Interruption: When the door or window is opened, the magnet moves away from the reed switch, breaking the magnetic field. This causes the reed switch to open the circuit, interrupting the flow of current. This change in the circuit state is detected by the security system, triggering an alert or activating other security measures.
6. Real-Time Monitoring: The MC-38 offers an instantaneous response. As soon as the magnetic field is detected or interrupted, the switch reacts immediately, providing real-time monitoring of the door or window status.

Pinout of the Module:

The MC-38 white wired magnetic contact reed switch kit consists of two parts: the switching part and the magnetic part. The switching part, which is the reed switch and pigtail that is connected to the alarm system, has two wires, typically colored red and black. 

It is important to note that the polarity of the wires does not matter for the MC-38 kit. That is, the red wire can be connected to either the positive or negative input of the alarm system, and the black wire can be connected to either the positive or negative ground of the alarm system.

Applications:

• Home Security Systems: The MC-38 is extensively used in residential security systems to monitor the opening and closing of doors and windows. It helps detect unauthorized access and triggers alarms or alerts to notify homeowners of potential intrusions.
• Commercial Security: The module is also widely deployed in commercial establishments, such as offices, stores, and warehouses. It ensures that the security system is alerted when doors or windows are opened outside of designated hours or without proper authorization.
• Access Control Systems: The MC-38 can be integrated into access control systems to monitor entry and exit points. It provides a reliable means of detecting door status changes, ensuring that access is granted or denied appropriately based on the system's rules.
• Industrial Security: In industrial settings, the MC-38 is utilized to enhance security and safety measures. It can be installed on doors, gates, or equipment enclosures to monitor access and ensure compliance with safety protocols.
• Building Automation: The module finds applications in building automation systems, where it assists in monitoring and controlling the status of doors and windows. It enables energy-saving measures by ensuring that HVAC systems or lighting are adjusted based on the opening or closing of doors or windows.
• Asset Protection: The MC-38 can be used to safeguard valuable assets, such as safes, cabinets, or display cases. By installing the module, any unauthorized access attempts can be detected and thwarted.
• Vehicle Security: The module can be employed in automotive security systems to monitor the opening and closing of doors or windows in vehicles. It provides an additional layer of protection against theft or unauthorized entry.
• IoT Applications: With the rise of the Internet of Things (IoT), the MC-38 can be integrated into IoT devices for remote monitoring and control. It allows for real-time status updates on doors or windows, enabling users to monitor their premises from anywhere using connected devices.

Circuit:

Library: 

No library is needed to work with the sensor.

Code:

const int reedSwitchPin = 2;   // Define the pin connected to the reed switch
const int ledPin = 13;         // Define the pin connected to the LED
int reedSwitchState = 0;       // Variable to store the state of the reed switch

void setup() {
  pinMode(ledPin, OUTPUT);     // Set the LED pin as an output
  pinMode(reedSwitchPin, INPUT);  // Set the reed switch pin as an input
  Serial.begin(9600);          // Initialize serial communication at 9600 bits per second
}

void loop() {
  reedSwitchState = digitalRead(reedSwitchPin);  // Read the state of the reed switch

  if (reedSwitchState == HIGH) {  // If the reed switch is closed
    digitalWrite(ledPin, HIGH);  // Turn on the LED
    Serial.println("Door or window closed");  // Print a message to the serial monitor
  } else {  // If the reed switch is open
    digitalWrite(ledPin, LOW);   // Turn off the LED
    Serial.println("Door or window open");  // Print a message to the serial monitor
  }

  delay(500);  // Wait for half a second before checking the reed switch again
}

• In this code, the reedSwitchPin variable is assigned the pin number to which the reed switch is connected, and the ledPin variable is assigned the pin number to which the LED is connected.

•  In the setup() function, the pin modes are set, with ledPin configured as an output and reedSwitchPin configured as an input. Serial communication is also initialized with a baud rate of 9600.

•  The loop() function continuously reads the state of the reed switch using digitalRead() and stores the state in the reedSwitchState variable. If the reed switch is closed (reedSwitchState == HIGH), the LED is turned on using digitalWrite() and a message is printed to the serial monitor. If the reed switch is open, the LED is turned off and a corresponding message is printed.A delay of 500 milliseconds is added at the end of each iteration of the loop to provide a short delay before checking the reed switch again.

Technical Details: 

• Model: MC-38 NC
• Material: Plastic + Magnet
• Color: White
• Size: 27x14x7.6mm
• Action distance: 18mm ± 6mm
• Rated voltage: 12 (V)
• Switch withstand voltage: 100VDC
• Load current: 300mA

Resources:

• Datasheet
  
  

Comparisons:

The MC-38 magnetic contact reed switch kit and optical sensors are two different types of sensors that can be used to detect the opening and closing of doors or windows in home security applications.

The MC-38 kit uses a magnetic contact reed switch that is activated by the presence or absence of a magnetic field, while optical sensors use a light source and a receiver to detect changes in light intensity caused by the opening or closing of a door or window.

Compared to optical sensors, the MC-38 kit has some advantages and disadvantages:

Advantages of the MC-38 kit:

• Simple and reliable technology: the reed switch has no moving parts, making it very reliable over time.
• Lower cost: the MC-38 kit is usually less expensive than optical sensors.
• Easy to install: the MC-38 kit comes with adhesive tape and can be installed easily on any door or window frame.

Disadvantages of the MC-38 kit:

• Limited range: the MC-38 kit has a limited range of action (18mm ± 6mm), which means that the magnet and the switch must be very close to each other for the switch to activate.
• Susceptibility to interference: the MC-38 kit can be affected by other magnetic fields in the environment, which can cause false positives or false negatives.
• Limited functionality: the MC-38 kit can only detect the opening and closing of doors or windows, and cannot be used for other applications.

Advantages of optical sensors:

• Higher range: optical sensors can detect changes in light intensity from a greater distance than the MC-38 kit can detect a magnetic field.
• Less susceptible to interference: optical sensors are less susceptible to interference from other sources, making them more reliable in noisy environments.
• Can be used for multiple applications: optical sensors can be used for various other applications such as motion detection, light sensing, etc.

Disadvantages of optical sensors:

• Higher cost: optical sensors are generally more expensive than the MC-38 kit.
• More complex technology: optical sensors use more complex technology than magnetic contact reed switches, which can make them more difficult to set up and maintain.
• Require a clear line of sight: optical sensors require a clear line of sight between the emitter and the receiver, which can limit their usefulness in certain applications where obstacles are present.