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WEEK 10 Output devices

GROUP ASSIGNMENT:

The PCB board I made the other week for TREADMILL has a 3 pin header I can use now for my output devices. Below there’s a code example I made with help of Chat GPT for 3 output devices I’ll be using in THE REWARD MACHINE (Servo Motor, Neo Pixel Led Strip and Buzzer) As well with a video of current measurement.

SERVO MOTOR

#include <ESP32Servo.h>

#define LED_PIN D7
#define BUTTON_PIN D9

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

void setup() {
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  myservo.attach(D6);  // attaches the servo on pin D6 to the Servo object
}

void loop() {
  if (digitalRead(BUTTON_PIN) == LOW) {  // Check if button is pressed
    for (int i = 0; i < 3; i++) {  // Repeat the cycle 3 times
      digitalWrite(LED_PIN, HIGH);  // Turn LED on
      myservo.write(0);  
      delay(300);

      myservo.write(180);
      delay(300);
    }
    digitalWrite(LED_PIN, LOW);  // Turn LED off
  }
}

NEO PIXEL LED STRIP WS2812B

#include <Adafruit_NeoPixel.h>

#define LED_PIN D6
#define NUM_LEDS 38  // Number of LEDs in the strip

Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUM_LEDS, LED_PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  strip.begin();
  strip.show();  // Initialize all pixels to 'off'
}

void loop() {
  rainbowEffect();  // Always run the rainbow effect
}

void rainbowEffect() {
  uint16_t i, j;
  for (j = 0; j < 256; j++) {
    for (i = 0; i < strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel((i + j) & 255));
    }
    strip.show();
    delay(20);
  }
}

uint32_t Wheel(byte WheelPos) {
  WheelPos = 255 - WheelPos;
  if (WheelPos < 85) {
    return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
  }
  if (WheelPos < 170) {
    WheelPos -= 85;
    return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
  }
  WheelPos -= 170;
  return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
}

SPEAKER

const int buttonPin = D9;  // Button pin
const int ledPin = D6;     // LED pin

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);  // Use internal pull-up
}

void loop() {
  int buttonState = digitalRead(buttonPin);

  if (buttonState == LOW) {  // Button pressed (LOW due to pull-up)
    digitalWrite(ledPin, HIGH);  // Turn LED ON
  } else {
    digitalWrite(ledPin, LOW);   // Turn LED OFF
  }
}

INDIVIDUAL ASSIGNMENT:

REWARD MACHINE KICAD SCHEMATIC AND PCB

Whole Process how to Use Kikad, FlaCam and Candle to produce the PCB is in the WEEK 08 https://fabacademy.org/2025/labs/benfica/students/daniel-osika/WEEK08/

This time I change the Footprint of Xiao board to make it detachable and added holes for mounting screws

kikad.jpg

kikad2.jpg

UPDATE: In the week of Embedded Networking I discovered that my SCL and SDA are connected to the wrong pins. It should be: SDA → pin D4 (number 5) SCL → pin D5 (number6)

pcb.jpg

pcbBack.jpg

During the FlatCam process I had some problems:

Some of the path were looking thinner then the others. I checked all my design rules in KiCad and everything was fine.

flatcamerror.jpg

I reinstalled the FlatCam program and the version x64 started crashing each time I was making ‘isolation routing’, so at this point I thought I would need to change the CAM program to something ealse… I reinstalled the program and the FlatCAM_beta_8.994_x86_installer.exe is the one thatg works good for me now.

THE CODE

after pressing the button: - the debug led should go ON only when the button is pressed, and OFF when the button is realised - the led strip increasing in blue colour from led 1 -37 and last one 38th is red - the buzzer increases the sound together with the led strip, makes a stronge sound on the last, 38th red led - the servo motor rotates after led strip sequence is finished

#include <Adafruit_NeoPixel.h>
#include <ESP32Servo.h>

#define BUTTON_PIN D7  // Button with pull-up resistor on D7
#define LED_PIN D2      // Debugging LED on D2
#define LED_STRIP_PIN D9 // Neopixel LED strip on D9
#define SPEAKER_PIN D6  // Buzzer on D6
#define SERVO_PIN D8    // Servo motor on D8
#define NUM_LEDS 38    // Total LEDs in strip

Adafruit_NeoPixel strip(NUM_LEDS, LED_STRIP_PIN, NEO_GRB + NEO_KHZ800);
Servo servoMotor;

void setup() {
    pinMode(BUTTON_PIN, INPUT_PULLUP);  // Set button pin as input with internal pull-up
    pinMode(LED_PIN, OUTPUT);     // Set LED pin as output
    pinMode(SPEAKER_PIN, OUTPUT); // Set buzzer pin as output
    strip.begin();
    strip.show(); // Initialize all pixels to 'off'
    servoMotor.attach(SERVO_PIN);
    servoMotor.write(90); // Stop position for continuous servo
}

void loop() {
    int buttonState = digitalRead(BUTTON_PIN); // Read button state

    if (buttonState == LOW) { // Button is active low due to pull-up resistor
        digitalWrite(LED_PIN, HIGH); // Turn on debug LED when button is pressed
        lightUpStripWithSound();
        strip.clear();  // Turn off all LEDs after animation
        strip.show();
        rotateServo();  // Start servo movement after LED sequence finishes
    } else {
        digitalWrite(LED_PIN, LOW);  // Turn off debug LED when button is released
    }
}

void lightUpStripWithSound() {
    for (int i = 0; i < NUM_LEDS; i++) {
        if (i < NUM_LEDS - 1) {
            strip.setPixelColor(i, strip.Color(0, 0, 255)); // LED blue for 1 to 37
        } else {
            strip.setPixelColor(i, strip.Color(255, 0, 0)); // Last LED (38) red
        }

        tone(SPEAKER_PIN, map(i, 0, NUM_LEDS - 1, 500, 2000), 100); // Increasing "ping"
        strip.show();
        delay(100); // Delay for effect
    }
    tone(SPEAKER_PIN, 2500, 300); // Final stronger ping
    delay(300);
    noTone(SPEAKER_PIN); // Stop buzzer
}

void rotateServo() {
    for (int i = 0; i < 2; i++) { // Move 0 → 180 → 0 two times
        servoMotor.write(180);
        delay(500); // Allow time to reach position
        servoMotor.write(0);
        delay(500); // Allow time to return
    }
}

Unfortunately I’m not able to write the code correctly. The debug led is ON during the whole time function is running (when the button is not pressed anymore) and the servo is going crazy.

I’m not understanding the problem because the code below works fine

THE CODE FOR THE SERVO TO MOVE ONLY FROM 0-180-0 TWICE AFTER PROSSING THE BUTTON

#include <ESP32Servo.h>

#define BUTTON_PIN D7  // Button with pull-up resistor on D7
#define SERVO_PIN D8   // Servo motor on D8

Servo servoMotor;
bool buttonPressed = false;

void setup() {
    pinMode(BUTTON_PIN, INPUT_PULLUP);  // Set button pin as input with internal pull-up
    servoMotor.attach(SERVO_PIN);
    servoMotor.write(0); // Start at 0 degrees
}

void loop() {
    if (digitalRead(BUTTON_PIN) == LOW) { // Button pressed
        if (!buttonPressed) { // Only trigger once per press
            buttonPressed = true;
            rotateServoTwice();
        }
    } else {
        buttonPressed = false; // Reset when button is released
    }
}

void rotateServoTwice() {
    for (int i = 0; i < 2; i++) { // Move 0 → 180 → 0 two times
        servoMotor.write(180);
        delay(500); // Allow time to reach position
        servoMotor.write(0);
        delay(500); // Allow time to return
    }
}

FILES:

KICAD

TREADMILL

FLATCAM

TREADMILL

CHECKLIST:

Group assignment:

  • Measure the power consumption of an output device.
  • Document your work on the group work page and reflect on your individual page what you learned.

Individual assignment:

  • Add an output device to a microcontroller board you've designed and program it to do something.

Learning outcomes:

  • Demonstrate workflows used in controlling an output device(s) with MCU board you have designed.

Have you answered these questions?

  • Linked to the group assignment page.
  • Documented how you determined power consumption of an output device with your group.
  • Documented what you learned from interfacing output device(s) to microcontroller and controlling the device(s).
  • Linked to the board you made in a previous assignment or documented your design and fabrication process if you made a new board.
  • Explained the programming process/es you used.
  • Explained any problems you encountered and how you fixed them.
  • Included original source code and any new design files.
  • Included a ‘hero shot’ of your board.