This example shows you how you can read the analog voltage on the A1 pin on your board.

In the example below, click theDownload Project Bundle button below to download the necessary libraries and thecode.py file in a zip file. Extract the contents of the zip file, open the directoryCircuitPython_Essentials/CircuitPython_Analogin/ and then click on the directory that matches the version of CircuitPython you're using and copy the contents of that directory to yourCIRCUITPY drive.

YourCIRCUITPY drive should now look similar to the following image:

# SPDX-FileCopyrightText: 2018 Kattni Rembor for Adafruit Industries## SPDX-License-Identifier: MIT"""CircuitPython Essentials Analog In example"""import timeimport boardfrom analogio import AnalogInanalog_in = AnalogIn(board.A1)def get_voltage(pin):    return (pin.value * 3.3) / 65536while True:    print((get_voltage(analog_in),))    time.sleep(0.1)

# SPDX-FileCopyrightText: 2018 Kattni Rembor for Adafruit Industries## SPDX-License-Identifier: MIT"""CircuitPython Essentials Analog In example"""import timeimport boardfrom analogio import AnalogInanalog_in = AnalogIn(board.A1)def get_voltage(pin):    return (pin.value * 3.3) / 65536while True:    print((get_voltage(analog_in),))    time.sleep(0.1)

Creating the analog input

analog1in= AnalogIn(board.A1)

Creates an object and connects the object to A1 as an analog input.

get_voltage Helper

get_voltage(pin) is our little helper program. By default, analog readings will range from 0 (minimum) to 65535 (maximum). This helper will convert the 0-65535 reading frompin.value and convert it a 0-3.3V voltage reading.

Main Loop

The main loop is simple. Itprints out the voltage as floating point values by callingget_voltage on our analog object. Connect to the serial console to see the results.

Changing It Up

By default the pins arefloating so the voltages will vary. While connected to the serial console, try touching a wire fromA1 to theGND pin or3Vo pin to see the voltage change.

You can also add a potentiometer to control the voltage changes. From the potentiometer to the board, connect theleftpin toground, themiddlepin toA1, and therightpin to3V. If you're using Mu editor, you can see the changes as you rotate the potentiometer on the plotter like in the image above! (Click the Plotter icon at the top of the window to open the plotter.)

Wire it up

The list below shows wiring diagrams to help find the correct pins and wire up the potentiometer, and provides more information about analog pins on your board!

Reading Analog Pin Values

Theget_voltage() helper used in the potentiometer example above reads the raw analog pin value and converts it to a voltage level. You can, however, directly read an analog pin value in your code by usingpin.value. For example, to simply read the raw analog pin value from the potentiometer, you would run the following code:

import timeimport boardfrom analogio import AnalogInanalog_in = AnalogIn(board.A1)while True:    print(analog_in.value)    time.sleep(0.1)

import timeimport boardfrom analogio import AnalogInanalog_in = AnalogIn(board.A1)while True:    print(analog_in.value)    time.sleep(0.1)

This works with any analog pin or input. Use the<pin_name>.value to read the raw value and utilise it in your code.