43 lines
1.4 KiB
Markdown
43 lines
1.4 KiB
Markdown
# On Pin Pressed
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Start an [event handler](/reference/event-handler) (part of the program
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that will run when something happens, like when a button is pressed).
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This handler works when you press pin `0`, `1`, or `2` together with `GND`.
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When you are using this function in a web browser, click the pins on the screen instead of the ones
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on the BBC micro:bit.
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If you hold the `GND` pin with one hand and touch pin `0`, `1`, or `2` with the other,
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a very small (safe) amount of electricity will flow through your body and back into
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the micro:bit. This is called **completing a circuit**. It's like you're a big wire!
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```sig
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input.onPinPressed(TouchPin.P0, () => {
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})
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```
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## ~hint
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This function works best when the BBC micro:bit is using batteries for power,
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instead of the USB cable.
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## ~
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### Example: pin pressed counter
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This program counts how many times you press the `P0` pin.
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Every time you press the pin, the program shows the number of times on the screen.
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```blocks
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let count = 0
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basic.showNumber(count, 100)
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input.onPinPressed(TouchPin.P0, () => {
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count = count + 1
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basic.showNumber(count, 100)
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})
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```
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### See also
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[BBC micro:bit pins](/device/pins), [pin is pressed](/reference/input/pin-is-pressed), [analog read pin](/reference/pins/analog-read-pin), [analog write pin](/reference/pins/analog-write-pin), [digital read pin](/reference/pins/digital-read-pin), [digital write pin](/reference/pins/digital-write-pin)
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