Reed Switch
𧲠Reed Switch
π Overview
A Reed Switch is a magnetically operated switch that opens or closes in the presence of a magnetic field.
π Commonly used in:
πͺ Door/window sensors
π Speed detection
π€ Robotics
π Security systems
π§ Working Principle
Inside the switch β two thin ferromagnetic metal reeds sealed in a glass tube
When a magnet comes close:
Reeds attract each other β circuit closes (ON)
When magnet moves away:
Reeds separate β circuit opens (OFF)
π Based on magnetic attraction (no power needed to operate)
π Infographic Summary
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β 𧲠REED SWITCH β
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β π― Function: Magnetic switch β
β β‘ Power: Not required β
β π Output: Digital (ON/OFF) β
β π¦ Type: Normally Open/Closedβ
β π Operation: Contact-based β
β π§ Trigger: Magnetic field β
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π Basic Connection
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β Reed Switch β
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β Terminal 1
β Terminal 2
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π Works like a simple switch
π Connect in series with circuit or microcontroller input
βοΈ Types of Reed Switch
π Normally Open (NO)
OFF by default, turns ON near magnet
π Normally Closed (NC)
ON by default, turns OFF near magnet
π Changeover (SPDT)
Switches between two contacts
π Key Features
𧲠Magnetic field detection
β‘ No external power required
π§ Simple and reliable
π¦ Compact and sealed
π Low power consumption
π§ͺ Applications
πͺ Door/window alarm systems
π² Bicycle speedometer
π Wheel rotation sensing
π€ Robotics limit switches
π‘ Proximity detection
π§° Industrial automation
π Interfacing
Compatible with:
π΅ Arduino
π‘ ESP32 / ESP8266
π Raspberry Pi
π Connect one terminal to GND, other to digital input (use pull-up resistor)
π Working Example
π Door Sensor System:
Door closed β magnet near β switch ON
Door open β magnet away β switch OFF β alarm triggered
β οΈ Important Notes
β οΈ Fragile (glass enclosure)
β οΈ Limited switching current
β οΈ Can wear out with very frequent switching
β οΈ Sensitive to strong magnetic fields
π Reed Switch vs Hall Effect Sensor
| Feature | Reed Switch | Hall Sensor |
|---|---|---|
| Output | Mechanical ON/OFF | Electronic signal |
| Durability | Moderate | High |
| Speed | Slower | Faster |
| Power Requirement | No | Yes |
π‘ Pro Tip
Place magnet very close (few mm) for reliable operation
Use with pull-up resistor to avoid floating signals
π Perfect for simple, low-cost magnetic detection projects
