pxt-calliope/docs/reference/pins/analog-read-pin.md
2016-11-01 17:44:37 -07:00

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# Analog Read Pin
Read an **analog** signal (`0` through `1023`) from the
[pin](/device/pins) you say.
```sig
pins.analogReadPin(AnalogPin.P0)
```
### Parameters
* ``name`` is a [string](/reference/types/string) with the name of the pin
you say (`P0` through `P4`, or `P10`)
### Returns
* a [number](/reference/types/number) from `0` through `1023`
This program reads pin `P1` and shows the number
on the LED screen.
```blocks
basic.forever(() => {
let value = pins.analogReadPin(AnalogPin.P1)
basic.showNumber(value)
});
```
#### ~hint
If you are using **analog read pin** with another @boardname@ running **analog write pin**, then things can get tricky. Remember that the @boardname@ that runs **analog set pin** writes 0's and 1's at a very high frequency to achieve an average of the desired value. Sadly, if you try to read that average from another @boardname@, then the @boardname@ will either read 0 or 1023. You could try to read a higher number of values (e.g. a million) in a loop, then computer then average. Alternatively, you can plug in a capacitor in-between the two @boardname@s.
#### ~
### See also
[@boardname@ pins](/device/pins),
[on pin pressed](/reference/input/on-pin-pressed),
[analog write pin](/reference/pins/analog-write-pin),
[digital read pin](/reference/pins/digital-read-pin),
[digital write pin](/reference/pins/digital-write-pin)