Keyes KY-021 Magnetic reed switch

Product detailed description

The Keyes KY-021 module with a reed switch is used for the non-contact detection of a magnet's proximity. The glass ampoule with the reed switch closes the moment a magnetic field comes into proximity, and the module passes a digital level directly to the microcontroller input. You can use it as a limit switch, a door or window opening detector, a tachometer, or as a simple position sensor in mechanical assemblies. The module contains only a reed switch and a 10 kΩ resistor, making it undemanding in terms of wiring and power supply.

Specifications:

• Sensor type: reed switch, normally open (NO)
• Supply voltage: 3.3 – 5 V DC
• Output type: digital (0/1)
• Output function: idle state without a magnet; the contact closes and the logic level changes when a magnet is brought close
• Components: reed switch, 10 kΩ resistor, 3× pin header
• Pins:
  • S: signal output (MCU digital input)
  • Middle pin (+): power supply 3.3 – 5 V
  • –: GND
• Detection distance: approx. 10 – 15 mm (depends on the strength and orientation of the magnet used)
• Dimensions:
  • Board: approx. 18.5 × 15 mm
  • Pin pitch: 2.54 mm
• Compatibility: Arduino, ESP32, ESP8266, Raspberry Pi, STM32 and other MCUs with 3.3V/5V logic
• Programming: no library required – digitalRead() function is sufficient
• Operating temperature: −10 °C to +70 °C

Package contents:

• 1× Keyes KY-021 module with reed magnetic switch

Note:

• Magnet is not included.
• The reed contact is enclosed in a glass ampoule – handle the module with care, as the ampoule is fragile.
• This product is not a standalone functional unit and may require professional installation.
• Product images are for illustrative purposes only and may sometimes differ from the actual appearance of the item. However, this does not change its basic properties.