readVoltage

Read voltage from analog pin on Arduino hardware

Add-On Required: This feature requires the MATLAB Support Package for Arduino Hardware add-on.

Syntax

voltage = readVoltage(a,pin)

voltage = readVoltage(___,Name=Value)

Description

voltage = readVoltage(a,pin) reads the voltage on the specified analog input pin on Arduino^® hardware.

voltage = readVoltage(___,Name=Value) specifies additional options using one or more name-value arguments. You can use this syntax only when you connect the Arduino hardware to your computer over USB. (since R2025a)

Examples

Read Voltage from Analog Pin

Create an Arduino object and read voltage from analog input pin.

a = arduino;
readVoltage(a,'A4')

ans = 1.0606

Specify Number of Samples and Sample Rate

Since R2025a

Create an arduino object and read the voltage from an analog pin for a given number of samples at a specified sample rate.

a = arduino("COM24");
readVoltage(a,"A3",NumSamples=5,SampleRate=200)

ans = 5×1

    3.2551
    3.2551
    3.2551
    3.2600
    3.2551

Specify Duration and Sample Rate

Since R2025a

Create an arduino object and read the voltage from an analog pin for a given duration and at a specified sample rate.

a = arduino("COM24");
readVoltage(a,"A3",Duration=0.2,SampleRate=50)

ans = 10×1

    3.2502
    3.2551
    3.2551
    3.2551
    3.2551
    3.2551
    3.2551
    3.2551
    3.2551
    3.2551

Specify Number of Samples and Output Format

Since R2025a

Create an arduino object and read the voltage from an analog pin for a given number of samples. Return the read voltage as a matrix.

a = arduino("COM24");
readVoltage(a,"A3",NumSamples=5,OutputFormat="matrix")

ans = 5×1

    3.2551
    3.2551
    3.2551
    3.2551
    3.2551

Specify Duration, Sample Rate, and Output Format

Since R2025a

Create an arduino object and read the voltage from an analog pin for a given duration and sample rate. Return the read voltage as a timetable.

a = arduino("COM24");
readVoltage(a,"A3",Duration=0.1,SampleRate=200,OutputFormat="timetable")

ans=20×1 timetable
      Time       Voltage
    _________    _______

    0 sec        3.2551 
    0.005 sec    3.2502 
    0.01 sec     3.2551 
    0.015 sec    3.2551 
    0.02 sec     3.2502 
    0.025 sec    3.2551 
    0.03 sec     3.2551 
    0.035 sec    3.2551 
    0.04 sec     3.2551 
    0.045 sec    3.2551 
    0.05 sec     3.2551 
    0.055 sec    3.2551 
    0.06 sec     3.2551 
    0.065 sec    3.2551 
    0.07 sec     3.2551 
    0.075 sec    3.2551 
      ⋮

Input Arguments

a — Arduino hardware connection

object

Arduino hardware connection, specified as an object. Use the arduino object to create the connection.

pin — Analog pin number

character vector

Analog pin number on the physical hardware, specified as a character vector.

Note

If you connect to the ESP32 board, the pin number must always correspond to a digital pin. For details, see Pin-mapping for ESP32 Boards.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: readVoltage(a,pin,Duration=0.1,SampleRate = 200,OutputFormat=“timetable”)

NumSamples — Number of output sample voltages

positive integer

Since R2025a

Number of output sample voltages, specified as a positive integer.

NumSamples cannot be greater than 1 if:

• You set the TraceOn property of the arduino object to True.

• Arduino hardware communicates with the host computer over Wi-Fi^® or Bluetooth^®.

Example: readVoltage(a,pin,NumSamples=5)

Data Types: double

Duration — Duration for acquisition of voltage

positive integer

Since R2025a

Duration for acquisition of voltage in seconds, specified as positive integer.

Example: readVoltage(a,pin,Duration=5)

Data Types: double

SampleRate — Sample rate at which to read data from the analog pin

100 (default) | positive integer in the range [1, 500]

Since R2025a

Sample rate at which to read data from the analog pin in samples/second, specified as positive integer in the range [1, 500].

Example: readVoltage(a,pin,NumSamples=5,SampleRate=200)

Data Types: double

OutputFormat — Output format

matrix (default) | timetable

Since R2025a

Output format, specified as matrix or timetable.

Example: readVoltage(a,pin,NumSamples=5,OutputFormat=“timetable”)

Data Types: string | character vector

Note

You can specify the Duration or NumSamples argument, with or without the SampleRate and OutputFormat arguments.

Output Arguments

voltage — Voltage read from analog pin

positive integer | matrix | timetable

Voltage read from an analog pin on an Arduino hardware, returned as positive integer, matrix, or timetable.

Note

The readVoltage function continuously acquires data when you specify the NumSamples, Duration, and SampleRate arguments.. As it is a blocking function call, MATLAB^® waits until the voltage acquisition is complete and all the specified samples are collected before proceeding to the next operation.

More About

Code Generation Using MATLAB Function Block

• Use readVoltage in a MATLAB Function block with the Simulink^® Support Package for Arduino Hardware to generate code that can be deployed on Arduino Hardware. This functionality is not supported when you use this function with the name-value arguments.

• Configure the Arduino peripherals to the appropriate mode using configurePin before using readVoltage in the MATLAB Function block.

Version History

Introduced in R2014b

R2025a: Enhancing voltage data acquisition capabilities with readVoltage function

You can now use the readVoltage function to acquire voltage data at a higher sampling rate. This function also allows you to acquire voltage data at the specified sample rate for a specific duration or number of samples, and return data in a particular output format.