Circuit Documentation

Summary

This project is an Automatic Color Change Detection and Timing system. It detects a color change in a solution, times the change, provides a sound cue, and sends the time to a computer via Bluetooth. The timer can be reset, and the sound cue stopped using a Bluetooth keyboard. The system includes an Arduino UNO, a spectral sensor, an OLED display, a NeoPixel ring, a Bluetooth module, a piezo buzzer, and various passive components.

Component List

1. SparkFun Spectral Sensor Breakout - AS7262 Visible (Qwiic)

   • Description: A spectral sensor used for detecting color changes.
   • Pins: 3.3V, LED_DRV, CTS, DTR, GND, TX/SDA, RX/SCL, !INT, !RST

2. Arduino UNO

   • Description: The main microcontroller used for processing and control.
   • Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0, A1, A2, A3, A4, A5, SCL, SDA, AREF, D13, D12, D11, D10, D9, D8, D7, D6, D5, D4, D3, D2, D1, D0

3. 0.96" OLED

   • Description: A small OLED display used for visual output.
   • Pins: GND, VDD, SCK, SDA

4. 1N4007 Rectifier Diode

   • Description: A diode used for rectification.
   • Pins: Cathode, Anode

5. NPN Transistor (EBC)

   • Description: A transistor used for switching.
   • Pins: emitter, base, collector

6. Resistor

   • Description: A resistor with a resistance of 1000 Ohms.
   • Pins: pin1, pin2

7. Adafruit 24 NeoPixel Ring

   • Description: A ring of 24 NeoPixels used for visual effects.
   • Pins: VDD, OUT, IN, GND

8. HC-05 Bluetooth Module

   • Description: A Bluetooth module used for wireless communication.
   • Pins: Key, VCC, TXD, RXD, State, GND

9. Piezo Buzzer

   • Description: A buzzer used for sound cues.
   • Pins: pin 1, pin 2

10. Electrolytic Capacitor

    • Description: A capacitor with a capacitance of 1000 Farads.
    • Pins: -, +

Wiring Details

SparkFun Spectral Sensor Breakout - AS7262 Visible (Qwiic)

• 3.3V connected to Arduino UNO 3.3V
• GND connected to Arduino UNO GND
• TX/SDA connected to Arduino UNO A4
• RX/SCL connected to Arduino UNO A5

Arduino UNO

• 3.3V connected to SparkFun Spectral Sensor Breakout - AS7262 Visible (Qwiic) 3.3V
• GND connected to SparkFun Spectral Sensor Breakout - AS7262 Visible (Qwiic) GND, Piezo Buzzer pin 2, NPN Transistor (EBC) emitter, 0.96" OLED GND, Adafruit 24 NeoPixel Ring GND, HC-05 Bluetooth Module GND
• A4 connected to SparkFun Spectral Sensor Breakout - AS7262 Visible (Qwiic) TX/SDA, 0.96" OLED SDA
• A5 connected to SparkFun Spectral Sensor Breakout - AS7262 Visible (Qwiic) RX/SCL, 0.96" OLED SCK
• 5V connected to Adafruit 24 NeoPixel Ring VDD, HC-05 Bluetooth Module VCC, Electrolytic Capacitor +
• D9 connected to Piezo Buzzer pin 1
• D10 connected to HC-05 Bluetooth Module TXD
• D11 connected to HC-05 Bluetooth Module RXD
• D6 connected to Resistor pin2

0.96" OLED

• VDD connected to Arduino UNO 3.3V
• GND connected to Arduino UNO GND
• SDA connected to Arduino UNO A4
• SCK connected to Arduino UNO A5

Adafruit 24 NeoPixel Ring

• VDD connected to Arduino UNO 5V
• GND connected to Arduino UNO GND, Electrolytic Capacitor -
• IN connected to NPN Transistor (EBC) base

HC-05 Bluetooth Module

• VCC connected to Arduino UNO 5V
• GND connected to Arduino UNO GND
• TXD connected to Arduino UNO D10
• RXD connected to Arduino UNO D11

Piezo Buzzer

• pin 1 connected to Arduino UNO D9
• pin 2 connected to Arduino UNO GND

NPN Transistor (EBC)

• emitter connected to Arduino UNO GND
• base connected to Adafruit 24 NeoPixel Ring IN
• collector connected to Resistor pin1

Resistor

• pin1 connected to NPN Transistor (EBC) collector
• pin2 connected to Arduino UNO D6

Electrolytic Capacitor

• + connected to Arduino UNO 5V
• - connected to Adafruit 24 NeoPixel Ring GND

Code Documentation

/*
 * Project: Automatic Color Change Detection and Timing
 * Description: This project detects a color change in a solution, times the change,
 *              provides a sound cue, and sends the time to a computer via Bluetooth.
 *              The timer can be reset and the sound cue stopped using a Bluetooth
 *              keyboard.
 * Enhancements: Optimized color detection, debouncing logic, enhanced Bluetooth
 *               communication, and logging for diagnostics.
 */

#include <Adafruit_AS726x.h>
#include <Wire.h>
#include <SoftwareSerial.h>

Adafruit_AS726x ams;
SoftwareSerial BTSerial(10, 11); // RX, TX

const int buzzerPin = 9;
const int buttonPin = 2;

unsigned long startTime = 0;
bool colorChanged = false;
bool timing = false;

const int debounceDelay = 50; // milliseconds
unsigned long lastDebounceTime = 0;
int lastButtonState = HIGH;

unsigned long previousMillis = 0;
const long interval = 1000; // 1 second

void setup() {
  pinMode(buttonPin, INPUT);
  pinMode(buzzerPin, OUTPUT);
  BTSerial.begin(9600);
  if (!ams.begin()) {
    Serial.println("AS726x not detected. Check wiring.");
    while (1);
  }
  ams.enableIndicatorLED(true);
  ams.setMeasurementMode(AS726x_4CHAN_2);
  ams.setGain(AS726x_GAIN_64X);
  ams.setIntegrationTime(50);
}

void loop() {
  int buttonState = digitalRead(buttonPin);
  if (buttonState != lastButtonState) {
    lastDebounceTime = millis();
  }
  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (buttonState == LOW) {
      resetTimer();
    }
  }
  lastButtonState = buttonState;

  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;
    ams.startMeasurement();
    if (ams.dataReady()) {
      uint16_t r = ams.readRed();
      uint16_t g = ams.readGreen();
      uint16_t b = ams.readBlue();
      if (detectColorChange(r, g, b)) {
        if (!timing) {
          startTime = millis();
          timing = true;
        } else if (!colorChanged) {
          unsigned long elapsedTime = millis() - startTime;
          colorChanged = true;
          soundCue();
          sendTime(elapsedTime);
        }
      }
    }
  }
}

bool detectColorChange(uint16_t r, uint16_t g, uint16_t b) {
  static uint16_t prevR = 0, prevG = 0, prevB = 0;
  if (abs(r - prevR) > 50 || abs(g - prevG) > 50 || abs(b - prevB) > 50) {
    prevR = r;
    prevG = g;
    prevB = b;
    return true;
  }
  return false;
}

void soundCue() {
  tone(buzzerPin, 1000);
  delay(1000);
  noTone(buzzerPin);
}

void sendTime(unsigned long time) {
  BTSerial.print