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Machine Lab | Feb 10 & 12 2026
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Machine Lab | Feb 10 & 12 2026

Machine Lab | Feb 10 & 12 2026

adahafizh adahafizh
February 12, 2026
5 min read
machine-lab
feb-10

DC Motor and Potentiometers.

For this week’s testing with DC Motor, I found it intriguing with some problems that came along with it, and somehow the method to fixing it just works? Anyhow, I began by continuing off from last week’s code when the machine was working fine. Then, I added a potentiometer to control the speed and direction.

src/components/Callout.astro
// THIS IS FOR POTENTIOMETER CONTROLLING THE SPEED


int in1 = 8; // H-bridge inputs
int in2 = 9;
int ConA = 10; // Controller A (ENA)
int potPin = A0; // Potentiometer Analog Input
int speed1; // Variable for Motor Speed


void setup() {
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(ConA, OUTPUT);


  Serial.begin(9600);


  digitalWrite(in1, LOW);
  digitalWrite(in2, HIGH);
}


void loop() {
  int val = analogRead(potPin);
  // We map the values of potentiometer to PWM range
  speed1 = map(val, 0, 1023, 0, 255);


  // Then we feed it into the motor
  analogWrite(ConA, speed1);


  // To make things easier, I mapped the speed into percentages so I can read it easier to debug it as well
  int percentage = map(speed1, 0, 255, 0, 100);


  // Printing the values
  Serial.print("Potentiometer: ");
  Serial.print(val);
  Serial.print(" | PWM Signal: ");
  Serial.print(speed1);
  Serial.print(" | Motor Speed: ");
  Serial.print(percentage);
  Serial.println("%");


  delay(100);  // Small delay so the text doesn't fly by too fast to read
}

Initially, after tweaking some parts of the code to fit the potentiometer, the motor suddenly stopped working and had no sounds coming off of it. When I checked the potentiometer using Serial.write, I noticed that it was jumping up and down in a weird fashion. Somewhere afterwards, I changed the potentiometer and/or then plugged it directly into the Arduino board to see if it would fix anything.

deck
Values jumping up and down

Funny enough, this caused some weird movement and whirring sounds when plugged (and tried with the new code). Then, I fiddled around with the input locations both in code and wiring, and somehow it worked??? Not sure how this turned out to be.

deck
It’s finally working yeay!

DIY Conveyor Belt

Unfortunately the IM Lab does not have rubber bands. Fortunately, the place is also filled with dozens of substitute materials. And even more fortunately, we are here to be challenged and face them.

In the morning, I saw a YouTube short where the video shows a vertical conveyor belt / elevator system. In it, I notice that most of the structures were made with wood and perhaps cardboard, a.k.a soft materials. What caught my attention was the trick part to create elastic enough materials to allow the belt to work. Inspired by this, I cut up some paper and began working on the conveyor system.

deck
Initial testing
deck
Added marker-colored double-taped papers to the belt

Schematics & Code Snippets

deck
Circuit Schematics

Feb 9, 2026 21:30 - After plunging head first into the bed, I pondered and wondered. Perhaps I should’ve added a switch button to control the direction of the DC motor and potentiometer to control the speed instead. While I did not have access to the parts in IM Lab, I could use Tinkercad to do the work!

src/components/Callout.astro
// THIS IS THE CODE WITH SWITCH BUTTON TO CONTROL THE MOTOR DIRECTION
// WE ACHIEVE THIS BY USING INPUT_PULLUP TO KEEP THE INTERNAL RESISTOR TO HIGH; PRESSING IT BRINGS IT TO LOW


int in1 = 8;
int in2 = 9;
int ConA = 10;
int potPin = A0;
int buttonPin = 2; // Added button pin


bool isForward = true;   // Variable to keep track of the motor direction
bool lastButtonState = HIGH; // Variable to keep track of the button state


void setup() {
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(ConA, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP); // Internal resistor


  Serial.begin(9600);
}


void loop() {
  // 1. We first check the button state
  bool currentButtonState = digitalRead(buttonPin);


  // If button is pressed (LOW) and it wasn't pressed before, then
  if (currentButtonState == LOW && lastButtonState == HIGH) {
    isForward = !isForward; // Toggle the direction (true becomes false, etc)
    delay(50); // For ease-ness sake, we add a delay here so it doesn't jump. But improvements can be made using no delay() clocks for future codes.
  }
  lastButtonState = currentButtonState;


  // 2. Then, we set the direction of the motor
  if (isForward) {
    digitalWrite(in1, HIGH);
    digitalWrite(in2, LOW);
  } else {
    digitalWrite(in1, LOW);
    digitalWrite(in2, HIGH);
  }


  // 3. Handling Speed
  int val = analogRead(potPin);
  int speed1 = map(val, 0, 1023, 0, 255);
  analogWrite(ConA, speed1);


  // 4. Debugging
  Serial.print("Dir: ");
  Serial.print(isForward ? "FORW" : "BACK");
  Serial.print(" | Speed: ");
  Serial.print(map(speed1, 0, 255, 0, 100));
  Serial.println("%");


  delay(10);
}

Also, I blipped out and forgot to commit to Github before making changes and afterwards, making the code to be one and done kinda thing. Turns out tinkering makes your forget about time :P

Future Improvements and Considerations

When I first thought about using conveyor belt, theres two ways that I was thinking about it (especially after visiting the caraousel from two years ago) that are:

  • IF I want the pipes to move similar to how it moves in the game, I could place the belt horizontally or vertically and the pipes aligning with it.
  • Considering that there has to be a horizontal movement by either the bird or the pipes, I chose conveyor belt best because springs will make it doing motion in a single place.

Extra Resources