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9. Output devices

Group assignment:

  • Measure the power consumption of an output device.

  • Document your work to the group work page and reflect on your individual page what you learned

To see our group assignment click here

Individual assignment:

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

For this week’s assignment, we chose to use a servo motor and a LCD 2004 screen with the electronic board we made in Week 8 (Electronics production).

Servo motor

to use the servo-motor we have followed the wiring below.

Since the signal pin of the servo motor must be connected to a PWM pin, we have chosen pin 18. Once the wiring is finished we move on to the programming. For the programming of our circuit board we will use the example program “Sweep” from the library “ESPservo.h”.

ESP32_Servo_Sweep.ino
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#include <ESP32Servo.h>

Servo myservo;  // create servo object to control a servo
// 16 servo objects can be created on the ESP32

int pos = 0;    // variable to store the servo position
// Recommended PWM GPIO pins on the ESP32 include 2,4,12-19,21-23,25-27,32-33 
// Possible PWM GPIO pins on the ESP32-S2: 0(used by on-board button),1-17,18(used by on-board LED),19-21,26,33-42
#if defined(ARDUINO_ESP32S2_DEV)
int servoPin = 16;
#else
int servoPin = 18;
#endif

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, 1000, 2000); // attaches the servo on pin 18 to the servo object
    // using default min/max of 1000us and 2000us
    // 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
    }
}

After uploading the code on the card here is the result.

LCD 2004 screen

to use the LCD 2004 screen we have followed the wiring below

Indeed, the LCD 2004 with the associated I2C module uses the I2C protocol to communicate with the microcontroller ESP32 or the default pins of the I2C protocol on the ESP32 are GPIO21 and GPIO22. once the wiring is finished we move on to the programming. For the programming of our circuit we have modified the example program “HelloWorld” of the library “LiquidCrystal_I2C.h” as below.

ESP32_LCD.ino
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#include <Wire.h> 
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,20,4);  // set the LCD address to 0x27 for a 16 chars and 2 line display

void setup()
{
  lcd.init();
  // Print a message to the LCD.
  lcd.backlight();
  lcd.setCursor(4,0);
  lcd.print("Hello world!");
  lcd.setCursor(6,1);
  lcd.print("Welcome");
   lcd.setCursor(6,2);
  lcd.print("to  the");
   lcd.setCursor(1,3);
  lcd.print("Fab Lab Y'ELLO LAB");
}


void loop()
{

}

after uploading the code on the card here is the result.

Files

Last update: May 21, 2023