Microbit and KY-021 Mini reed switch module
In this article, we connect a KY-021 Mini reed switch module to our Microbit – we will use Makecode and show the JavaScript and Python output as well
The KY-021 Mini reed switch module is a If a magnetic field is detected, the two input pins are short-circuited by pulling them towards each other.
The most common type of reed switch contains a pair of magnetizable, flexible, metal reeds whose end portions are separated by a small gap when the switch is open. The reeds are sealed within a tubular glass envelope. A magnetic field from an electromagnet or a permanent magnet will cause the reeds to attract each other, thus completing an electrical circuit. The spring force of the reeds causes them to separate, and open the circuit, when the magnetic field ceases.
Parts Required
Name | Link | |
Microbit | ![]() |
|
37 in one sensor kit | ![]() |
|
Connecting cables | ![]() |
Schematic/Connection
MICRO:BIT | SENSOR |
---|---|
0 | Signal |
3,3 V | +V |
GND | GND |
Example
All of these are from the Microsoft Makecode site
MakeCode
Python
pins.set_pull(DigitalPin.P0, PinPullMode.PULL_UP) def on_forever(): if pins.digital_read_pin(DigitalPin.P0) == 1: basic.show_icon(IconNames.NO) else: basic.show_icon(IconNames.YES) basic.pause(1000) basic.forever(on_forever)
JavaScript
pins.setPull(DigitalPin.P0, PinPullMode.PullUp) basic.forever(function () { if (pins.digitalReadPin(DigitalPin.P0) == 1) { basic.showIcon(IconNames.No) } else { basic.showIcon(IconNames.Yes) } basic.pause(1000) })
Output
by default the led matrix will display an X, if you place a magnet close to the switch the display will change to a tick mark