[Template page: copy but do not modify the original] Double Transducer: Light to Sound

Final images

Detail photos

Final project movies

Student 1 documentation video with caption. 

Student 2 documentation video with caption, same advice and requirements as listed above.

Narrative description

Progress images

Discussion

Functional block diagram and electrical schematic

Code

/*

    Arduino code basic structure sketch

    Demonstrates how to structure an Arduino sketch so that

    the loop contains four basic elements:

      1) read inputs (gather information from the world)

      2) compute and make decisions based on those inputs

      3) drive outputs (effect different actuators in the world)

      4) report information back to the user

    While not every interactive device necessarily needs all

    four of these steps in the loop, many often do.

    For the purpose of this demonstration sketch, this code

    is written for a device that will read a button as an

    input and drive an LED as an output. When the button is

    held down, the LED will be brighter, and when the button

    isn't held down, the LED will be dimmer.

    Pin mapping:

    Arduino pin | role  | details

    ------------------------------

    5             input   momentary button

    8             output  external LED

    Released to the public domain by the author, January 2024

    Robert Zacharias, rzachari@andrew.cmu.edu

*/

/*  Pin mapping section of code, creating variables to store

    pin numbers. Note that the "const int" data type is used

    instead of plain "int" because the pin numbers are

    constant--they will never change in the code.

    All-caps names are used by convention for variables whose

    values won't change.

*/

const int BUTTON_PIN = 5;

const int LED_PIN = 8;

void setup() {

  /*  We need to ensure that the pins are set up for their

      electrical roles as input or output. (Note that it is

      possible to change pin mode in the loop, but usually you

      don't need to do that so it's easier to do just once in

      the setup.)

  */

  pinMode(BUTTON_PIN, INPUT);

  pinMode(LED_PIN, OUTPUT);

  /*  We also need to turn on the serial library so that the

      Arduino will be able to send data back to the computer.

  */

  Serial.begin(9600);

}

void loop() {

  /*  Step 1 is gathering information from the world and

      saving it into whatever variable(s) are appropriate.

  */

  // create an "int" variable called "buttonState" with

  // a starting value of 0

  int buttonState = 0;

  // Actually read the button pin and find out if the button

  // is pressed or not, then save the result into buttonState.

  // We use the command "digitalRead" to tell the Arduino to check

  // if a certain input pin has a LOW (0V) or HIGH (5V) voltage.

  buttonState = digitalRead(BUTTON_PIN);

  // At this point buttonState will be "HIGH" (if the button was pressed)

  // or "LOW" if it was not.

  /*  Step 2 is using gathered data to change different variables,

      or doing "math" (can take many forms) to make decisions

  */

  // make an "int" variable to store the brightness of the LED

  // using a starting value of 0

  int ledBrightness = 0;

  // change the value of ledBrightness based on whether or not

  // the button was pressed

  if (buttonState == HIGH) { // if the button was pressed

    ledBrightness = 200;     // make ledBrightness store 200, i.e. bright

  }

  else if (buttonState == LOW) { // otherwise, if the button wasn't pressed

    ledBrightness = 30;    // make ledBrightness store 30, i.e. dim

  }

  /*  Step 3 is driving outputs, in this case lighting the LED */

  // The command "analogWrite" will tell the Arduino to adjust the

  // brightness of the attached LED.

  analogWrite(LED_PIN, ledBrightness);

  // Step 3 is very simple in this sketch; that line is all there is to it.

  /*  Step 4 is reporting information back to the user, and in this

      case we'll use the serial monitor (a display on the attached computer

      screen) to know what the Arduino is thinking.

  */

  Serial.print("buttonState = "); // just write that text to the screen

  Serial.print(buttonState); // then send the value of the variable

  Serial.print(", ledBrightness = "); // write that text to the screen

  Serial.println(ledBrightness); // send the value of the variable

  delay(10);

}