pxt-calliope/docs/reference/input/on-pin-event.md
Juri Wolf 2457725e0c
V4updates (#185)
* update 32KB

* reorder buttonEvents to have clicked as default

* update event block documentation file path

* remove on pin released documentation

* update shims, enums and package-lock
2022-05-09 10:10:17 -07:00

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Markdown

# On Pin Event
Start an [event handler](/reference/event-handler) (part of the
program that will run when something happens, like when a button is
pressed). This handler works when you touch pin `0`, `1`, or `2`
together with `GND`, and release it within 1 second.
When you are using this function in a web
browser, click the pins on the screen instead of the ones on the
@boardname@.
If you hold the `GND` pin with one hand and touch pin `0`, `1`, or `2`
with the other, a very small (safe) amount of electricity will flow
through your body and back into the @boardname@. This is called
**completing a circuit**. It's like you're a big wire!
```sig
input.onPinTouchEvent(TouchPin.P0, ButtonEvent.Click, () => {
})
```
## ~hint
This function works best when the @boardname@ is using batteries for power,
instead of the USB cable.
## ~
## Parameters
* ``name`` means the pin that is being pressed, either `P0`, `P1`, or `P2`
## Pin presses in action
See how the @boardname@ detects a press at a pin or on something connected to a pin in this video:
https://www.youtube.com/watch?v=GEpZrvbsO7o
## Example: pin pressed counter
This program counts how many times you press the `P0` pin.
Every time you press the pin, the program shows the number of times on the screen.
```blocks
let count = 0
basic.showNumber(count)
input.onPinTouchEvent(TouchPin.P0, ButtonEvent.Click, () => {
count = count + 1
basic.showNumber(count)
})
```
## See also
[@boardname@ 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)