Driving a Step Motor with a Teensy Board Using PsychToolbox

I would like to make the following RRST equipment and conduct an experiment.

The experiment was designed using psychtoolbox. Sending commands from MATLAB should drive the stepmotor through the teensy board.

The main program works, but the step motor does not move. It was confirmed that there was nothing wrong with the motor itself. Can I use MATLAB to drive a teensy board-linked step motor? I’m wondering if the serial communication part is wrong.

RespiroceptionMethodsPaper/task at main · embodied-computation-group/RespiroceptionMethodsPaper · GitHub

function [moved, currPosition] = moveResp(respDevice, newPosition, unitscale)

rescale = 1; % rescale motor step values

try

if rescale

% Rescale new position input to motor step value

[motorStepVal] = scale2motorstep(newPosition, unitscale);

else

motorStepVal = newPosition;

end

moveToHere = strcat(sprintf('%03d', motorStepVal));

% Move & update new current position output

writeline(respDevice, moveToHere)

currPosition = newPosition;

moved = 1;

catch

currPosition = NaN;

moved = 0;

end

end

+) arduino code

/*==========================================================================

===========================================================================*/

#include “TeensyStep.h”

#define endstopPin 7

#define enablePin 8

#define dirPin 9

#define stepPin 10

#define MAXPOSITION 37000

long initial_homing=-200;

//Serial interface setup

const byte numChars = 90;

char receivedChars[numChars];

boolean newData = false;

long stepperPosition = 0;

Stepper motor(stepPin, dirPin);

StepControl controller; // Use default settings

void setup()

{

Serial.begin(9600);

motor

.setAcceleration(10000) // 20 000

.setMaxSpeed(16000);

// Setting up Endstop pin

pinMode(endstopPin,INPUT_PULLUP);

// Setting up enable pin and enable the driver

pinMode(enablePin,OUTPUT);

digitalWrite(enablePin,LOW);

// Setup LED pin for debugging

pinMode(LED_BUILTIN, OUTPUT);

// Home the stepper

homeStepper();

}

void loop()

{

recvWithEndMarker();

showNewNumber();

motor.setTargetAbs(stepperPosition);

// Set the target position:

if(stepperPosition <= MAXPOSITION && stepperPosition >= 0)

{

motor.setTargetAbs(stepperPosition);

controller.move(motor); // Do the move

}

else if (stepperPosition > MAXPOSITION)

{

stepperPosition = MAXPOSITION;

Serial.print("Out of range! Setting position to MAXPOSITION: ");

Serial.println(stepperPosition);

motor.setTargetAbs(stepperPosition);

controller.move(motor); // Do the move

}

else if (stepperPosition < 0)

{

homeStepper();

}

}

// Serial receive function

void recvWithEndMarker() {

static byte ndx = 0;

char endMarker = ‘\n’;

char rc;

if (Serial.available() > 0) {

rc = Serial.read();

Serial.print((char)rc);

if (rc != endMarker) {

receivedChars[ndx] = rc;

ndx++;

if (ndx >= numChars) {

ndx = numChars - 1;

}

}

else {

receivedChars[ndx] = '\0'; // terminate the string

ndx = 0;

newData = true;

}

}

}

void showNewNumber() {

if (newData == true) {

Serial.print("Current position: ");

Serial.println(stepperPosition);

stepperPosition = 0; // new for this version

stepperPosition = atol(receivedChars); // new for this version

Serial.print("New position: ");

Serial.println(receivedChars);

newData = false;

}

}

// Homing routine

void homeStepper(){

Serial.println(“Fast Homing begins:”);

int endstopStatus = digitalRead(endstopPin);

Serial.println(endstopStatus);

while (digitalRead(endstopPin)) { // Make the Stepper move CCW until the switch is activated

motor.setTargetRel(initial_homing); // Set the position to move to

controller.move(motor); // Start moving the stepper

delay(4);

}

Serial.println(“Fast Homing ended”);

endstopStatus = digitalRead(endstopPin);

Serial.println(endstopStatus);

Serial.println(“Stepping forward”);

Serial.println( motor.getPosition());

motor.setTargetRel(2000);

controller.move(motor);

delay(600);

endstopStatus = digitalRead(endstopPin);

Serial.println("Re-homing ");

Serial.println(endstopStatus);

Serial.println( motor.getPosition());

while (digitalRead(endstopPin)) { // Make the Stepper move CCW until the switch is activated

motor.setTargetRel(-5); // Set the position to move to

controller.move(motor); // Start moving the stepper

Serial.println( motor.getPosition());

delay(3);

}

endstopStatus = digitalRead(endstopPin);

Serial.println("Homed ");

Serial.println(endstopStatus);

stepperPosition = 0;

motor.setPosition(0);

}

Answer 1

[Angelo Yeo]

Teensy is not supported in MATLAB R2023b. It is supported in MATLAB R2024b and later. For a full list of supported hardware, please refer to the link below:

https://www.mathworks.com/hardware-support.html?q=&page=1

[연주]

Thank you for your answer.

The paper I am referring to was published in 2021.

I use Teensy 3.1. It appears to control the teensy board in a different way.

Answer 2

[Aravind]

Hi @연주,

While controlling a stepper motor directly through MATLAB is not feasible, you can achieve this using Simulink. Starting with MATLAB R2024a, the Simulink Support Package for Arduino Hardware allows you to deploy models to Teensy boards. More information is available here: https://www.mathworks.com/hardware-support/arduino.html#simulink. This page also provides guidance on setting up the core libraries for the Teensy board in MATLAB R2024a.

Once the core libraries are set up, you can use the "IO Device Builder" app to incorporate external Teensy C++ libraries for stepper motor control and create a Simulink block for this purpose. Detailed information about the "IO Device Builder" app can be found here: https://www.mathworks.com/help/releases/R2023b/supportpkg/arduino/io-device-builder.html. The block you create can be deployed to a Teensy board using code generation, enabling you to control the stepper motor from Simulink.

Since MATLAB and Simulink are well integrated, you can run and control the Simulink model from MATLAB code, allowing you to indirectly control the stepper motor through MATLAB.

Here are some resources to help you get started with the "IO Device Builder" app:

1. Introduction to the "IO Device Builder" app: https://www.mathworks.com/help/releases/R2023b/supportpkg/arduino/ug/io-device-builder.html
2. Example with the DHT11 sensor: https://www.mathworks.com/help/releases/R2023b/supportpkg/arduino/ref/dht11-relative-humidity-temperature-io-device-builder.html
3. Example with the ADXL343 sensor: https://www.mathworks.com/help/releases/R2023b/supportpkg/arduino/ref/adxl343-read-acceleration-io-device-builder.html
4. Video tutorial on creating custom sensor blocks for Arduino in Simulink: https://www.mathworks.com/videos/how-to-build-custom-sensor-blocks-for-arduino-in-simulink-1704432957396.html

I hope this helps!