/*
 * Potentiometer Tester with Calibration Feature
 * Creator: Chad Kapper from HackMakeMod Inc.
 * For ESP8266
 * This sketch is designed to test potentiometers, using a button to set the low and high calibration points.
 * It visualizes the potentiometer's value on a strip of WS2812 LEDs. Pressing the button at a low value sets the lower limit,
 * and pressing it at a high value sets the upper limit of the potentiometer's range. The LEDs light up based on the
 * potentiometer's current position within the calibrated range.
 */

#include <FastLED.h>

// Pin definitions
#define POT_PIN A0         // Analog pin for potentiometer
#define BUTTON_PIN D1      // Button pin for calibration
#define LED_PIN D0         // Digital pin to control the LED strip
#define LED_COUNT 20       // Number of LEDs in the strip
#define THRESHOLD 5        // Minimum change in potentiometer value to update LEDs

CRGB leds[LED_COUNT];      // Array to store the LED colors
int prevValue = 0;         // Stores the previous potentiometer value for comparison
int highValue = 1023;      // Initial high calibration value (max value of potentiometer)
int lowValue = 0;          // Initial low calibration value (min value of potentiometer)

void setup() {
  Serial.begin(115200);
 
  pinMode(BUTTON_PIN, INPUT_PULLUP); // Initialize the button as an input with an internal pull-up resistor

  FastLED.addLeds<WS2812, LED_PIN, GRB>(leds, LED_COUNT); // Initialize the LED strip
 
  FastLED.setBrightness(30); // Set a moderate brightness level
 
  FastLED.show(); // Ensure all LEDs are off initially
 
  Serial.println("Setup complete, awaiting button press...");
}

void loop() {
  int potValue = analogRead(POT_PIN); // Read the current value of the potentiometer
  Serial.print("Potentiometer Value: ");
  Serial.println(potValue);

  // Check if the button is pressed (logic LOW if using INPUT_PULLUP)
  if(digitalRead(BUTTON_PIN) == LOW) {
    Serial.println("Button pressed");
    // Calibrate the low or high value based on the current potentiometer reading
    if(potValue < 300) { // Threshold to differentiate between low and high calibration
      lowValue = potValue;
      Serial.print("New lowValue: ");
      Serial.println(lowValue);
    } else {
      highValue = potValue;
      Serial.print("New highValue: ");
      Serial.println(highValue);
    }
    potValue = 0; // Reset potValue to avoid immediate recalibration effect
    FastLED.show(); // Update LED strip to reflect any changes
  }

  // Update LEDs only if the change in potentiometer value exceeds the threshold
  if(abs(potValue - prevValue) >= THRESHOLD) {
    prevValue = potValue; // Update previous value for next comparison
    int numLEDS = map(potValue, lowValue, highValue, 0, LED_COUNT); // Map pot value to number of LEDs

    // Create a color gradient based on the current position within the calibrated range
    for(int i = 0; i < LED_COUNT; i++) {
      int red = i * (255 / LED_COUNT);
      int green = 255 - red;

      if(i < numLEDS) {
        leds[i] = CRGB(red, green, 0); // Set color based on position
      } else {
        leds[i] = CRGB::Black;  // Turn off LEDs beyond the current position
      }
    }
   
    FastLED.show(); // Update the LED strip with new colors
  }

  delay(30); // Short delay to debounce button and slow down the loop for readability
}