Week 12. Group / Mechanical design, Machine Design

This is group assignment page for West harima student :

Student

• Koharu Takeda

instructor

• Hiroe Takeda

group assignment

• design a machine that includes mechanism+actuation+automation+application
• build the mechanical parts and operate it manually
• document the group project and your individual contribution

hero slide

hero video

Idea and Task/Part

1.sketch

To begin, I made several suggestions.

I decided roughly what kind of design we would like.

I also made some sketches to determine details such as connections and specific sizes.

Finally, the volume of the project was so large that it was unlikely to be completed on time, so we decided to create the Conveyor belt sushi system.

person in charge	Task/Part
myself	Slide Rail Mechanical Design and production
instructor	Electronics Design and Production
group works	electrical wiring

Slide Rail Mechanism (Koharu part)

2.BOM

Product name	Number of units purchased	Price	links
NEMA17 Stepper Motor	2	2,400 (yen)	Amazon
GT2 Timing Belt	1	1,820 (yen)	Amazon
Electronic Switch Control Board DC 5V-36V	1	699 (yen)	Amazon
Wheelp V Wheel Plate Mini	1	1,579 (yen)	Amazon
Tamiya 54393 Type380 Sport-Tuned Motor	2	627 (yen)	Amazon
Switching Power Supply 12V30A	1	2,980 (yen)	Amazon
Aluminum frame 5 series 20x20 - 1200	1	1,060 (yen)	Misumi

3.Design and Assembly

3.0 frame

I purchased an aluminum frame from Misumi.

I inserted this into Fusion360 with 3D data.
Download ↓

• Fusion360

3.1 Stepping Motor

First, measure the parts to be used.
This process is very important for design.

I designed the parts to attach the motor to the frame in Fusion360.

• try1

It worked, but I had to come up with another design because the motor heats up and could unravel the PLA.

• try2

This time I think I have created a simple yet good design!

3.2 Pulley (side without motor)

I think we have designed this one well.

3.3 assembly

The design is output and attached to the frame.

Install using TM3 T-nuts.
Install the other side in the same manner.

Finally, the belt and wheels are attached to complete the process.

4.Case Design

Two DC motors, one stepping motor, and the part through which the pinball passes are incorporated.

Output completed! I spent so much time on this. It was very difficult to take pictures because I had so many supports on.

Actually.... We have tried our best to create a mechanism to launch a ping-pong ball, which was our first idea, but we decided that we could not make it due to time constraints and had to change our plans quickly. This 3D printed case was not adopted as a machine and is stored in my house.

5.Plate

I made a plate to put the plates on.

• disin(Fusion360)

Designed to allow for the installation of limit switches.

• 3D printing

Finish by filing the limit switch so that it can be easily turned on.

Electronics Design and Production (instructor part)

6.connections

In my case, I used Arduino Uno R4 Minima and connected as follows

ENA : 5
DIR : 6
PUL : 7

• Arduino Uno R4 Minima Pinuot

• Stepping motor operation check

int PUL=7; //define Pulse pin
int DIR=6; //define Direction pin
int ENA=5; //define Enable Pin
void setup() {
  pinMode (PUL, OUTPUT);
  pinMode (DIR, OUTPUT);
  pinMode (ENA, OUTPUT);

}

void loop() {
  for (int i=0; i<6400; i++)    //Forward 5000 steps
  {
    digitalWrite(DIR,LOW);
    digitalWrite(ENA,HIGH);
    digitalWrite(PUL,HIGH);
    delayMicroseconds(50);
    digitalWrite(PUL,LOW);
    delayMicroseconds(50);
  }
  for (int i=0; i<6400; i++)   //Backward 5000 steps
  {
    digitalWrite(DIR,HIGH);
    digitalWrite(ENA,HIGH);
    digitalWrite(PUL,HIGH);
    delayMicroseconds(50);
    digitalWrite(PUL,LOW);
    delayMicroseconds(50);
  }
}

• result

7.set limit switch

It is attached to both bridges and the part where the plate rides.

8.programming(final code)

stepping motor + limit switch x 3

This is the actual code used.

// Motor control pins
const int ENA = 5;   // ENA (Enable)
const int DIR = 6;   // DIR (Direction)
const int PUL = 7;   // PUL (Pulse)

// Limit switch pins
const int leftLimitPin = 2;   // Left-end limit switch
const int rightLimitPin = 3;  // Right-end limit switch
const int centerSwitchPin = 4; // Center switch (plate detection)

// Motor movement status
bool moving = false;
bool direction = true; // true = moving right, false = moving left

void setup() {
  // Set pin modes
  pinMode(ENA, OUTPUT);
  pinMode(DIR, OUTPUT);
  pinMode(PUL, OUTPUT);

  pinMode(leftLimitPin, INPUT_PULLUP);
  pinMode(rightLimitPin, INPUT_PULLUP);
  pinMode(centerSwitchPin, INPUT_PULLUP);  // Enable pull-up for center switch

  // Enable motor initially
  digitalWrite(ENA, HIGH);
  digitalWrite(DIR, direction);  // Set initial direction (right)
  digitalWrite(PUL, LOW);

  Serial.begin(9600);  // For debugging
}

void loop() {
  // Read center switch (LOW = plate present)
  bool centerPressed = digitalRead(centerSwitchPin) == LOW;

  // Debug: print center switch state
  Serial.print("Center switch state: ");
  Serial.println(centerPressed ? "Pressed (plate present)" : "Not pressed (no plate)");

  if (centerPressed) {
    moving = true;  // Start movement if plate is present
  } else {
    moving = false; // Stop if no plate
    digitalWrite(PUL, LOW);  // Stop motor
  }

  if (moving) {
    // Change direction if a limit switch is triggered
    if (digitalRead(leftLimitPin) == LOW) {
      direction = true;  // Move right
      digitalWrite(DIR, direction);
      Serial.println("Left limit reached → Reversing to right");
      delay(300);  // Debounce delay
    }

    if (digitalRead(rightLimitPin) == LOW) {
      direction = false;  // Move left
      digitalWrite(DIR, direction);
      Serial.println("Right limit reached → Reversing to left");
      delay(300);  // Debounce delay
    }

    // Move motor
    for (int i = 0; i < 64000; i++) {    // Advance 64000 steps
      digitalWrite(DIR, direction ? LOW : HIGH);  // Set direction
      digitalWrite(ENA, HIGH);  // Enable motor
      digitalWrite(PUL, HIGH);  // Pulse HIGH
      delayMicroseconds(20);    // Pulse width
      digitalWrite(PUL, LOW);   // Pulse LOW
      delayMicroseconds(20);    // Interval before next pulse
    }
  }
}

Once the code is written, it is complete!

wiring

Wiring was done by two people.

data file

• week12_sttepingmotor_Fusion360
• week12_poory_Fusion360
• week12_plate

possible improvements

• The base was a little unstable, so I thought it would be better if it were designed to be a little sturdier and more stable.

Problems and Solutions

• When installing the stepping motor, the distance between the holes that had been drilled for installation was narrower than the actual value, making it impossible to install the motor. Therefore, we re-measured and remade the model.