Jose Alegria - Fab Academy

Output Devices

Assignment

wHAT iS THE ASSIGNMENT ABOUT?

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

Group Assignment:

Measure the power consumption of an output device

1^st Step. Electronics design

Using the same board I designed for electronics design, I made a few changes:

- Removed the extra button and LED

- Added input and output pins to be able to connect and disconnect several peripherals to the board.

- Added 5V, 3.3 V and GND pins to be able to send signals to peripherals.

For this assignment, I attached a photo interrupter to get an input device and a buzzer as an output device. The photo interrupter is going to be connected to the 3.3V, GND and Pin 4. The buzzer will be connected to the pin 4 and GND.

Here is the final board:

2^nd Step. Electronics production

The process to make the electronics board is explained in this assignment:

07 - Electronics Design

3^rd Step. Code and programming

The process to program a board is explained in this assignment:

09 - Embedded Programming

To operate the output device, I had to tell the microprocessor where the input and output devices are going to be installed, that is the first part of the code I am going to use:

const int ledPin1 = 2;

const int buzzer = 9;

const int buttonPin = 4;

Then I had to tell it the function that they will be doing:

void setup() {

pinMode(ledPin1, OUTPUT);

pinMode(buzzer, OUTPUT);

pinMode(buttonPin, INPUT);

When that setup is done, then you can start telling the microprocessor what you want to be done and when:

void loop() {

pos = digitalRead(buttonPin);

if (pos != pos_guardada)

{

pos_guardada = pos;

cambio++;

Serial.print("Numero de cambios: ");

Serial.println(cambio);

t1 = millis();

}

if (millis()-t1>tiempo_lluvia) { cambio = 0;

}

if (cambio>2) {

lluvia = 1;

t2 = millis();

}

else { lluvia = 0;

}

if (lluvia==1) {

digitalWrite(ledPin1, HIGH);

i = 0;

do

{

digitalWrite(buzzer, HIGH);

delay(500);

digitalWrite(buzzer, LOW);

delay(500);

i++;

} while (i < 10);

}

else {

digitalWrite(ledPin1, LOW);

digitalWrite(buzzer, LOW);

}

}

Here, I am telling the microprocessor when I want the buzzer to start working (HIGH) and when to stop (LOW). I also wrote that the LED should turn on when the buzzer is working, but that is an extra that does not count toward this assignment.

This is a video of the board working as intended.

Conclussions

This assignment is the first one to show us how to tell the microprocessor what to do and when, the most difficult part was writing the code and there were most of the problems that emerged, they were solved by making small changes in the code to translate from the logic we are used to think with and the logic needed to program a processor.

Original Files

1. Code File

2. Electronics Design Files

Nueval Checklist

- 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 devices to microcontroller and controlling the devices.

- Described your design and fabrication process o r linked to previous examples.

- Explained the programming processes you used.

- Outlined problems and how you fixed them.

- Included original design files and code.

- Included a hero shot or video of your board.

2022