Week 9 — Output Devices

Process. This week I'm designing a board that controls a DC motor through a microcontroller. Components I'm using:

• Servo:MG90S
• MC: Seed Studio XIAO ESP32C3
• 3-6V DC motor: 130 DC Motor
• 5V Battery
• Single - sided copper board

Milling Machine Info: 1/32" Flat end mill; 1/64" flat end mill Software used: Fusion 360 - Schematic & Layout; Arduino IDE - Microcontroller coding.

The idea of Servo motor really interests me as I've never seen or come across this before. So I made a conceptual comparison table to summarize thigns I learned along the way

Servo Motor vs Conventional Motor

Feature	Servo Motor	Conventional Motor
Control	Precise position control via PWM signal	Continuous rotation only, no positional control
Feedback	Built-in potentiometer gives position feedback	No feedback — open loop system
Usage	Robotics, camera gimbals, locks, precise actuation	Fans, wheels, pumps, general spinning
Power	Usually 5–6V low power	Wide range (3–24V+)
Signal Pins	3 wires: Power, Ground, Signal	2 wires: Power, Ground


Schematic Design in Fusion




Finished Board with Bantam CNC milling machine


Servo Test Code

          /***********
          Modified 4 Nov 2025
          by Tony Wang

          see http://www.arduino.cc/en/Tutorial/Sweep
          for a description of the original code
          ***********/


          #include 

          Servo myservo;  // create servo object to control a servo

          int pos = 0;    // variable to store the servo position

          #if defined(CONFIG_IDF_TARGET_ESP32S2) || defined(CONFIG_IDF_TARGET_ESP32S3)
          int servoPin = 17;
          #elif defined(CONFIG_IDF_TARGET_ESP32C3)
          int servoPin = 7;  // Used
          #else
          int servoPin = 18;
          #endif
          // int servoPin = 4;

          void setup() {
              // Allow allocation of all timers
              ESP32PWM::allocateTimer(0);
              ESP32PWM::allocateTimer(1);
              ESP32PWM::allocateTimer(2);
              ESP32PWM::allocateTimer(3);
              myservo.setPeriodHertz(50);    // standard 50 hz servo
              myservo.attach(servoPin, 500, 2500); //
              // using default min/max of 500us and 2500us
              // different servos may require different min/max settings
              // for an accurate 0 to 180 sweep
          }

          void loop() {

              for (pos = 0; pos <= 180; pos += 1) { // goes from 0 degrees to 180 degrees
                  // in steps of 1 degree
                  myservo.write(pos);    // tell servo to go to position in variable 'pos'
                  delay(15);             // waits 15ms for the servo to reach the position
              }
              for (pos = 180; pos >= 0; pos -= 1) { // goes from 180 degrees to 0 degrees
                  myservo.write(pos);    // tell servo to go to position in variable 'pos'
                  delay(15);             // waits 15ms for the servo to reach the position
              }
          }

        

Motor Testing Code

          const int motorPin = 20;

          void setup() {
              pinMode(motorPin, OUTPUT);
          }

          void loop() {
              //Motor
              int speed;
              for (speed = 0; speed <=255; speed +=50){
              analogWrite(motorPin, speed);
              delay(1000);
              }
              analogWrite(motorPin, 0);
              delay(1000);
          }
          

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