DC MOTOR

For my DC motor, I made the H-bridge using the TB67H451AFNG; this is the schematic of my H-bridge.

To know the size my tracks should have, I calculated how much current would pass through the tracks when using the motor; I used the KiCad track calculator where I set the current to approximately 2A, in case my motor jams or something like that. With these parameters, I got a width of 0.8 mm.

The two inputs of the H-bridge connect to the outputs of my board from week 8 to be able to indicate direction; it is important that common grounds are connected."

CODE

const int IN1 = 27; // PINS WHERE WE ARE GOING TO CONNECT THE MOTOR INPUTS 
const int IN2 = 28; 

void setup() {  // We configure both pins as OUTPUT
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  detenerMotor();
}

void loop() {

  moverMotor(200); // We move the motor at a power of 
  // in one direction for 2 seconds
  delay(2000);
  
  detenerMotor();// We stop the motor 
  delay(1000);
  
  moverMotor(-200);// We start turning in the other direction
  delay(2000);
  
  detenerMotor();
  delay(1000);
}

void moverMotor(int velocidad) {
  if (velocidad > 0) {
    analogWrite(IN1, velocidad); // Function to make it turn to the right
    analogWrite(IN2, 0);// Sends IN2 to 0, so that one has no signal
  } else if (velocidad < 0) {
    analogWrite(IN1, 0); // Sets IN1 to 0, so that one has no signal
    analogWrite(IN2, abs(velocidad));// Function to make it turn to the left
  } else {
    detenerMotor();
  }
}

void detenerMotor() {
  analogWrite(IN1, 0);// Sets both IN to 0 so the motor does not turn
  analogWrite(IN2, 0);
}  


             

RESULT

OLED

I also used the OLED, but the libraries I tried to use with Arduino didn't work with my Xiao RP2350 because the libraries used the first I2C channel, which were the pins found underneath my XIAO, D13 and D14; so, since I didn't use these pins on my board, I switched to Visual to program it there.

The display OLED only has four pins to allow the display management.

VCC: Power Pin.

GND: Connect to microcontroller's ground.

SCL: I2C communication clock.

SDA: I2C Data line.

I2C is a two-wire serial communication protocol using a serial data line (SDA) and a serial clock line (SCL). The protocol supports multiple target devices on a communication bus and can also support multiple controllers that send and receive commands and data.

To make it easier to connect my OLED, I made a small board with the power and I2C pins to then connect two I2C devices to that board; this is the schematic and the fabrication files can be found in the files section.

VISUAL STUDIO CODE

In Visual Studio > libraries, we download the Raspberry Pi Pico library.

Now these new options will appear in the menu on the left; we press the Raspberry Pi Pico Project option.

Ready, we can start programming in Visual.

With Visual I could already turn on my OLED, but to write something I had to make functions to turn on each pixel depending on the letter, so I installed a library that could help me.

1. I opened this link GitHub.
2. Click on 'Download raw file' for the following three files: ssd1306.c, ssd1306.h, and font.h
3. Then we have to add them to our project's folder.
4. In the CMakeLists.txt file, we add the following line "ssd1306.c" in the add_executable section.

CODE

  
#include <stdio.h>
#include "pico/stdlib.h"
#include "hardware/i2c.h"

// We include the external library
#include "ssd1306.h" 

#define I2C_PORT i2c1
#define I2C_SDA  6  
#define I2C_SCL  7   

int main() {
    stdio_init_all();

    // 1. Initialize the I2C pins of your board (this stays the same)
    i2c_init(I2C_PORT, 400 * 1000);
    gpio_set_function(I2C_SDA, GPIO_FUNC_I2C);
    gpio_set_function(I2C_SCL, GPIO_FUNC_I2C);
    gpio_pull_up(I2C_SDA);
    gpio_pull_up(I2C_SCL);

    //Configure the screen using the library
    ssd1306_t disp;
    disp.external_vcc = false;
    // We initialize: object, width, height, I2C address, I2C port
    ssd1306_init(&disp, 128, 64, 0x3C, I2C_PORT); 

    //Clear the screen in case there was garbage
    ssd1306_clear(&disp);

    //(object, X, Y, text_size, message)

    ssd1306_draw_string(&disp, 10, 30, 1, "HELLO, I´M DANNA"); // Size 1

    //Send the data so they are shown on the OLED
    ssd1306_show(&disp);

    while (true) {
        sleep_ms(1000);
    }
}

  

RESULT

SERVO MOTOR

The servo operates off of a 4.0V to 7.2V power supply and it can draw as much as 0.5A.

Servomotor control relies on the transmission of electrical signals of adjustable duration, a technique known as pulse-width modulation (PWM), which is transmitted through the control line. This pulse defines the shaft's position; thus, depending on the signal's duration, the rotor will move to the required angle. For proper operation, the device requires a constant signal with a 20-millisecond (ms) interval between each pulse. The length of these pulses dictates the motor's final range of motion.

To test its operation, I made a code so that it would change position every time a button is pressed.

CODE

// Button and servo pins
const int botonPin = 0;  
const int servoPin = 3;   

int contadorToques = 0;  // Variable to store the number of button 
// presses that have occurred
bool ultimoEstadoBoton = HIGH; // Boolean variable to 
// remember the last state of the button. 

void setup() {
  // Configuration of my motor and my button
  pinMode(botonPin, INPUT_PULLUP); 
  pinMode(servoPin, OUTPUT);
  Serial.begin(115200);
}

void loop() {

  // Read the state of the button 
  int lecturaBoton = digitalRead(botonPin);

  if (lecturaBoton == LOW && ultimoEstadoBoton == HIGH) {
    delay(50); 
    contadorToques++; // We add 1 to the click counter to move the servo

    if (contadorToques > 3) {
      contadorToques = 1; // If 3 touches are reached, it returns to touch 1
    }
  }
  
  ultimoEstadoBoton = lecturaBoton; // Update the memory


  int tiempoAlto = 1000; // We start by setting the high time to 1ms, which would be 
  //0 degrees

  switch (contadorToques) {
    case 1:
      tiempoAlto = 1000;  // Mode 1: 0 degrees (1 ms pulse)
      break;

    case 2:
      tiempoAlto = 1500;  // Mode 2: 90 degrees (1.5 ms pulse)
      break;

    case 3:
      tiempoAlto = 2000;  // Mode 3: 180 degrees (2 ms pulse)
      break;
      
    default:
      tiempoAlto = 1000;  // Initial position before pressing the button
      break;
  }

// We generate the PWM
  digitalWrite(servoPin, HIGH);
  delayMicroseconds(tiempoAlto);           // Time that the pulse is high
  
  digitalWrite(servoPin, LOW);
  delayMicroseconds(20000 - tiempoAlto);   // Low time to complete the 20ms cycle
}

      
      

RESULT