I wanted to make a ghost chat which would allow the user to interact with “ghosts” that I programmed to be “detected” by a photosensor. By pushing the button, the user can ask questions and get an answer. I also initially wanted to program a theme song for each ghost that could run in the background or when someone asks for the ghosts’ favorite song, but that took a backseat when I realized how confused I actually was by interrupts. If I were to really make this perfect, I’d probably find a different sensor, and figure out a way to have the ghost answer questions that the user defines, as opposed to pre-programmed answers to pre-programmed questions.

ghost_chat_a2

vandezandeStateMachineInterrupt

The circuit shown above is a 3 pin led connected to a joystick. It uses the JoyStick movement to change the RGB values and the button press in the joystick is used to switch between states. The system has 5 states

1. All off
2.  Red constant, change G and B by moving the joystick
3.  Green constant, change R and G by moving the joystick
4. Blue constant, change others through joystick
5. All on.

Reflection:  if I were to redo this, I would transfer the states from 2, 3 and 4 making it a real color picker, and I also think the joystick button may not be ideal for an interrupt.

Code and Files: A2

I wanted to build upon and improve the previous assignment. The goal is to balance at a certain distance in order to turn on the LED, but done through a classic game of hot or cold. While it’s rather trivial, it has helped me to better understand the ultrasonic sensor and its possibilities. refining the sensor data and perfecting the timing is something that I’d like to explore further down the road.

The states are used in order to guide you through the game. State one lets you now that the game is ready, state two sets a random number for you to find using the ultrasonic sensor, and in state three…you find the number. Prompted in the serial monitor if you are getting warmer or colder.

Code:

Files:

Fritzing & Arduino Files

Reflection: If I were to update/re-do this, I would change the code so the interrupt is the proximity sensor rather than the switch. I would also change the light so the green represents light and proximity and red represents dark and proximity. This would align with my overarching ideal goal to make a front door security system. I would also change the light/dark reading to a boolean.

(My unstable hand is to blame for the flickering green light)

 // Define constant values.



// The wiring assignment.

#include



static const int SWITCH_PIN = 3;

static const int LED1Pin = 4;

static const int LED2Pin = 5;

static const int LED3Pin = 13;

static const int lightSensor = A0;

bool LEDState = false;

static const int sampleSize = 16;

unsigned int readings[sampleSize];

unsigned int sampleIndex = 0;

static const int nighttime = 50;

const int TRIG_PIN = 9;

const int ECHO_PIN = 8;

const int MAX_DISTANCE = 700;



NewPing sonar(TRIG_PIN, ECHO_PIN, MAX_DISTANCE);



void SwitchPressed()

{

if (digitalRead(SWITCH_PIN) == 1) {

LEDState = true;

}

else{

LEDState = false;

}

}



// ================================================================================

// Configure the hardware once after booting up. This runs once after pressing

// reset or powering up the board.



void setup()

{

// Initialize the serial UART at 9600 bits per second.



Serial.begin(115200);



pinMode(LED_BUILTIN, OUTPUT);



pinMode(SWITCH_PIN, INPUT);



pinMode(LED1Pin, OUTPUT);



pinMode(LED2Pin, OUTPUT);



pinMode(LED3Pin, OUTPUT);



pinMode(lightSensor, INPUT);



pinMode(TRIG_PIN, OUTPUT);



digitalWrite(TRIG_PIN, LOW);



// Initialize the echo pin for input.

pinMode(ECHO_PIN, INPUT);



attachInterrupt (digitalPinToInterrupt (SWITCH_PIN), SwitchPressed, CHANGE);



}



// ================================================================================

// Run one iteration of the main event loop. The Arduino system will call this

// function over and over forever.



void loop()

{



int photo = analogRead(lightSensor);



readings[sampleIndex] = photo;



if (sampleIndex < (sampleSize -1)) {

sampleIndex++;

}

else {

sampleIndex = 0;

}



int median = 0;

int low = 1024;

int high = 0;

int mean = 0;

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

mean += readings[i];

if (readings[i] < low) { low = readings[i]; } if (readings[i] > high) {

high = readings[i];

}

}

mean = mean / sampleSize;

bubbleSort();

median = readings[sampleSize / 2];



//TURNED ON, IDLE STATE



if (LEDState && sonar.ping_median() < 700 && mean > nighttime ) {

digitalWrite(LED1Pin, 255);

digitalWrite(LED2Pin, 0);

digitalWrite(LED3Pin, 0);

}



else if (LEDState && sonar.ping_median() < 700 && mean < nighttime ) {

digitalWrite(LED1Pin, 0);

digitalWrite(LED2Pin, 0);

digitalWrite(LED3Pin, 255);

}



//TURNED OFF



else if (!LEDState) {

digitalWrite(LED2Pin, 0);

digitalWrite(LED3Pin, 0);

digitalWrite(LED1Pin, 0);

}



else {

digitalWrite(LED2Pin, 255);

digitalWrite(LED3Pin, 0);

digitalWrite(LED1Pin, 0);

}



delay(500);

Serial.println("mean:");

Serial.println(mean);

Serial.println("median:");

Serial.println(sonar.ping_median());

}



// tigoe's sort for an array

void bubbleSort() {

int out, in, swapper;

for(out=0 ; out < sampleSize; out++) { // outer loop

for(in=out; in<(sampleSize-1); in++) { // inner loop if( readings[in] > readings[in+1] ) { // out of order?

// swap them:

swapper = readings[in];

readings [in] = readings[in+1];

readings[in+1] = swapper;

}

}

}

}

The system consists of 6 states in total – wait / read / output for detect mode and wait / read / record for record mode.

Demo:

Code and fritzing here

Due 23:59, 29 January 2018.  We will discuss in class on the 30th and suggest improvements or analyze different ways to resolve your problem.

Requirements

State a question or process you would like to solve. (Ex: “control the lights in a room based on a door being opened and curtains being opened or closed.”)  Create a physical interaction using a state machine driven by inputs and interrupts that collects data, interprets the data, then displays a result via console, LEDs, or other output devices. Speakers are acceptable but must be executed in a useful manner, kinematic solutions are also welcome.

The state machine should have at least three states not including on and off states.  Declare whether your states have an order or if any state can transition to another state.

Post a short video showing the various states, I suggest vimeo or youtube.   For your Arduino and Fritzing sketches, make a zip file or gzip/tar bundled and post that to the blog.