| title | layout | meta-description | share | author | about | cats | simple-description | date | date-updated |
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Reed Switch on the Microbit |
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How to use a reed switch in microbit projects. Ideal when making a buglar alarm. |
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jez |
A reed switch is triggered by a magnet. It is usually used above door as a buglar alarm. |
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Reed Switch |
2016-12-23 10:20:00 UTC |
2016-12-23 10:20:00 UTC |
A reed switch opens and closes in the presence of a magnet.
Typically they are usually open and closed when near a magnet.
The circuit and code for the reed switch is essentially the same as the button also covered in the components base.
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Reed switches can come in many different forms. Both of those below are reed switches. A search on Amazon on eBay will reveal many more types but they all work the same way.
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The reed switch on the right is enclosed in two-part module. The upper module contains the reed switch, the lower part is the magnet to trigger the reed switch. These are usually found in burglar alarm systems.
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The reed switch is connected to the microbit between pin0 and the 3v pin. The circuit is the same as the button example.
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Scroll 'burglar' on display if reed switch is open (the magnet is not present; eg. the door is open)
{% highlight python %} from microbit import *
while True: if pin0.read_digital(): # reed switch is closed. # magnet present display.show(Image.HAPPY) else: # reed swich open # magnet not present display.scroll('Buglar')
sleep(20)
{% endhighlight %}
- The microbit can be used as a reed switch with the onboard magnetometer.
compass.get_field_strength()returns the magnetic field in nano teslas.