KY-025 Magnetic Reed Switch Sensor Module with LM393

KY-025 Magnetic Reed Switch Sensor Module with LM393 is a sensitive magnetic proximity detection board built around a hermetically sealed glass reed switch tube and an onboard LM393 dual comparator IC. Designed for contactless sensing in security and automation projects, it delivers both an analog magnetic intensity voltage (AO) and an adjustable digital switching trigger (DO) whenever a magnetic field is introduced.

Key Features:

• Hermetically Sealed Glass Tube: Ferrous reeds enclosed in an inert gas glass capsule offer reliable, spark-free switching with long mechanical lifespan.
• Dual Output Capability: Provides both a real-time analog voltage output (AO) and a clean digital trigger output (DO).
• Onboard LM393 Comparator: High-precision comparator circuit ensures bounce-free digital switching transitions.
• Adjustable Magnetic Sensitivity: Onboard multi-turn potentiometer enables fine-tuning of the magnetic trigger distance.
• Dual LED Indicators: Features a power indicator LED and a digital output trigger LED for immediate visual diagnostics.
• Wide Compatibility: Functions seamlessly with standard 3.3V and 5V microcontrollers including Arduino, STM32, and Raspberry Pi.

Technical Specifications:

• Operating Voltage: 3.3V to 5.0V DC
• Operating Current: 15 mA typical
• Sensor Element: Normally Open (NO) glass reed switch contact
• Comparator IC: LM393 Precision Voltage Comparator
• Output Channels: AO (Analog real-time output) and DO (Digital switching output)
• Switching Capacity: Digital output drives microcontroller GPIO or direct optocoupler load
• Contact Rating: Rated for millions of contactless magnetic cycles
• Operating Temperature: -20°C to +85°C

Mechanical Specifications:

• Form Factor: Compact rectangular sensor module board
• PCB Construction: High-grade double-sided FR4 with green protective solder mask
• Mounting Hole: 1x 3.0 mm mounting screw hole for secure chassis placement
• Header Type: 4-pin male pin header (2.54mm pitch)
• Weight: Approximately 5.0 g

Dimensions:

• Overall Length: 36.0 mm
• Overall Width: 15.0 mm
• Overall Height: 14.0 mm

Pinout and Wiring:

• AO: Analog Output pin providing voltage proportional to reed resistance
• GND: Ground power connection (0V)
• VCC: Positive DC power supply (+3.3V to +5V DC)
• DO: Digital Output pin switching LOW when magnet closes the reed contacts

Datasheet Reference:

• Refer to the LM393 differential comparator datasheet and Reed Switch operating characteristics manual for magnetic flux sensitivity and contact closure speed specifications.

Commonly Used in:

• Door and window open/close security alarms and access monitoring systems
• Contactless liquid level float switch assemblies in water tanks and reservoirs
• Bicycle speedometers and rotating machinery tachometer pulse counting
• Limit switch detection in automation machinery avoiding physical contact wear

Applications:

• Magnetic door and window alarm sensor
• Liquid level float switch detection
• Contactless rotation and speed pulse counter
• Smart home intrusion monitoring
• Industrial safety interlock limit switch

Equivalent Models:

• KY-021 Mini Reed Switch Module
• MC-38 Magnetic Door Sensor Switch
• Hamlin 59025 Magnetic Reed Switch
• Standard NO Reed Switch Breakout

Package Includes:

• 1 × KY-025 Magnetic Reed Switch Sensor Module with LM393