pxt-calliope/docs/device/crocodile-clips.md

# crocodile clips

The large holes at the bottom of the board are designed to attach alligator/crocodile clips.
Register an event that will execute whenever the user attaches one side of the crocodile clip to the `GND` pin, then connects and disconnects the unattached side of the crocodile clip to pin `0`, `1`, or `2`.

### Example: on pin pressed with random numbers

This example displays a random number every time the crocodile clip holds  `GND` then connects and disconnects the `P0` pin. Each time the crocodile clip is firmly connected and disconnected from pin `P0`, the micro:bit will return a random Number between 0 and the parameter limit

```blocks
input.onPinPressed(TouchPin.P0, () => {
    basic.showNumber(Math.random(10))
})
```

### Connecting Crocodile Clips

![](/static/mb/crocodile-clips-2.jpg)

### See also

[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)