Double Transducer: Force to Light Color

Final images

Detail photos

Final project movies

Zarmond's documentation video showing force changing to light color.

Hua's documentation video showing force changing to light color with skipping the middle button.

Narrative description

When the force-sensitive resistor (FSR) senses an input from someone pressing on it, that will cause the hobby servo motor to move proportional to the amount of force being input (more force, closer to 180; less force, closer to 0). The motor moves a transparent sheet with a black gradient printed onto it. Based on the degree that the motor turns, the photo resistor will pick up more or less light because it will be covered by different levels of gradient on the transparent sheet. Lastly, the amount of light detected will affect the hue the NeoPixel ring displays.

Progress images

Discussion

Functional block diagram and electrical schematic

Code

/*

  Project 1: Double Transducer

  60-223 Intro to Physical Computing

  Zarmond and Hua

  When the force-sensitive resistor (FSR) senses an input from someone pressing

  on it, that will cause the hobby servo motor to move proportional to the amount

  of force being input (more force, closer to 180; less force, closer to 0). The

  motor moves a transparent sheet with a black gradient printed onto it. Based on

  the degree that the motor turns, the photo resistor will pick up more or less

  light because it will be covered by different levels of gradient on the

  transparent sheet. Lastly, the amount of light detected will affect the hue the

  NeoPixel ring displays.

  Pin mapping:

  Arduino pin | role  |  description

  -------------------------------------

  A3            input    FSR

  A2            output   servo motor

  A0            input    photoresistor

  8             output   neo pixel ring

  11            input    button

*/

//library for servo motor

#include <Servo.h>

//library for neopixel ring

#include <PololuLedStrip.h>

//library for LCD

#include <LiquidCrystal_I2C.h>

#include <Wire.h>

//library for mapping RGB to HSV

#include <math.h>

//pin assignments

const int FORCEPIN = A3;

const int SERVOPIN = A2;

const int PHOTOPIN = A0;

const int LEDPIN = 8;

const int LCDSDA = A4;

const int LCDSCL = A5;

const int BUTTONPIN = 11;

// number of LEDs in the neopixel

const int NUMLEDS = 12;

//creates Servo object to control a servo

Servo MOTORCONTROL;

//creates ledStrip object and specify the pin it will use.

PololuLedStrip<LEDPIN> ledStrip;

//creates an array for holding the color values for each LED

rgb_color colors[NUMLEDS];

//creates LCD object

LiquidCrystal_I2C screen(0x27, 16, 2);

//creates a hsl to rgb function

void hslToRgb(float h, uint8_t &r, uint8_t &g, uint8_t &b) {

  float c = 1.0f;  // chroma = (1 - |2l-1|) * s = 1

  float h_ = fmod(h, 360.0f) / 60.0f;

  float x = c * (1 - fabs(fmod(h_, 2) - 1));

  float r1, g1, b1;

  //match the condition selection of the function

  if (h_ < 1) {

    r1 = c;

    g1 = x;

    b1 = 0;

  } else if (h_ < 2) {

    r1 = x;

    g1 = c;

    b1 = 0;

  } else if (h_ < 3) {

    r1 = 0;

    g1 = c;

    b1 = x;

  } else if (h_ < 4) {

    r1 = 0;

    g1 = x;

    b1 = c;

  } else if (h_ < 5) {

    r1 = x;

    g1 = 0;

    b1 = c;

  } else {

    r1 = c;

    g1 = 0;

    b1 = x;

  }

  //give out final value

  r = (uint8_t)round(r1 * 255.0f);

  g = (uint8_t)round(g1 * 255.0f);

  b = (uint8_t)round(b1 * 255.0f);

}

void setup() {

  //FSR setup

  pinMode(FORCEPIN, INPUT);

  //servo setup

  pinMode(SERVOPIN, OUTPUT);

  MOTORCONTROL.attach(SERVOPIN);

  //photoresistor setup

  pinMode(PHOTOPIN, INPUT);

  //neopixel LED setup

  pinMode(LEDPIN, OUTPUT);

  //button setup

  pinMode(BUTTONPIN, INPUT_PULLUP);

  //serial port to send the data back to the computer (also for LCD use)

  Serial.begin(9600);

  //LCD setup

  // initialize the screen

  screen.init();

  // turn on the backlight to start

  screen.backlight();

}

void loop() {

  //skip the middle button code

  if (digitalRead(BUTTONPIN) == LOW) {

    //reads value from FSR input

    int forceVal = analogRead(FORCEPIN);

    //maps FSR inputs to hue

    int colorVal = map(forceVal, 0, 1023, 0, 360);

    int h = colorVal;

    uint8_t r8, g8, b8;

    hslToRgb(h, r8, g8, b8);

    for (int i = 0; i < NUMLEDS; i++) {

      colors[i] = rgb_color(r8, g8, b8);

    }

    ledStrip.write(colors, NUMLEDS);

    delay(10);

    //LCD code

    //sets cursor to top left corner

    screen.home();

    //maps FSR value to be 0-99

    forceVal = map(forceVal, 0, 1023, 0, 99);

    //input sensor's value

    screen.print("i:");

    screen.print(forceVal);

    delay(100);

    //set cursor to middle of screen for middle values

    screen.setCursor(6, 0);

    //maps servo motor position from 0-180 to 0-99

    int motorPos = map(motorPos, 0, 170, 0, 99);

    //servo motor/middle actuator value

    screen.print("m:");

    screen.print(motorPos);

    delay(100);

    //set cursor to middle of screen for middle value on second row

    screen.setCursor(6, 1);

    //maps photoresistor values to 0-99

    int lightVal = map(lightVal, 0, 1023, 0, 99);

    //photoresistor/middle sensor value

    screen.print("m:");

    screen.print(lightVal);

    delay(100);

    //set cursor to bottom corner of screen for output value

    screen.setCursor(12, 1);

    //maps neopixel values to 0-99

    colorVal = map(colorVal, 0, 360, 0, 99);

    //display neopixel color value

    screen.print("o:");

    screen.print(colorVal);

    delay(100);

    //if the button isn't pressed:

  } else {

  // step 1: read all of the sensors

    //reads value from FSR input

    int forceVal = analogRead(FORCEPIN);

    //create var to store light value, set light value from the photoresistor input data

    int lightVal = analogRead(PHOTOPIN);

  // step 2: make decisions about what to do

    //maps possible FSR inputs to servo motor range of 180deg.

    int motorPos = map(forceVal, 0, 1023, 0, 170);

    //maps photoresistor input data to hue

    int colorVal = map(lightVal, 300, 800, 0, 360);

  // step 3: drive all of the outputs

    //move the servo to that proportional position

    MOTORCONTROL.write(motorPos);

    delay(10);

    //make the NeoPixel emit said color

    int h = colorVal;

    uint8_t r8, g8, b8;

    hslToRgb(h, r8, g8, b8);

    for (int i = 0; i < NUMLEDS; i++) {

      colors[i] = rgb_color(r8, g8, b8);

    }

    ledStrip.write(colors, NUMLEDS);

    delay(10);    

  // step 4: report data back to the user

    //LCD code

    //sets cursor to top left corner

    screen.home();

    //maps FSR value to be 0-99

    forceVal = map(forceVal, 0, 1023, 0, 99);

    //input sensor's value

    screen.print("i:");

    screen.print(forceVal);

    delay(100);

    //set cursor to middle of screen for middle values

    screen.setCursor(6, 0);

    //maps servo motor position from 0-180 to 0-99

    motorPos = map(motorPos, 0, 170, 0, 99);

    //servo motor/middle actuator value

    screen.print("m:");

    screen.print(motorPos);

    delay(100);

    //set cursor to middle of screen for middle value on second row

    screen.setCursor(6, 1);

    //maps photoresistor values to 0-99

    lightVal = map(lightVal, 0, 1023, 0, 99);

    //photoresistor/middle sensor value

    screen.print("m:");

    screen.print(lightVal);

    delay(100);

    //set cursor to bottom corner of screen for output value

    screen.setCursor(12, 1);

    //maps neopixel values to 0-99

    colorVal = map(colorVal, 0, 360, 0, 99);

    //display neopixel color value

    screen.print("o:");

    screen.print(colorVal);

    delay(100);

  }

}

// source for hue to rgb code: https://stackoverflow.com/questions/2353211/hsl-to-rgb-color-conversion