/*
  Arduino | hardware-help
  Tyby Allx 9/9/25 — 11:25 AM
  Hello, I tried replicating this project
  https://youtu.be/HkyMUBDLYUo?si=zxNtcyAFVbEg3SvO
  Unfortunately, when more than 1 row of leds is opened,
  the matrix gets a flicker effect, it's not that bad
  but I would like to know if there is anything specific
  in the code that makes it act this way or it's caused
  by the led matrix
*/

#include "LedControl.h"

const int DATA_PIN =  2;
const int LOAD_PIN =  3;
const int CLOCK_PIN = 4;
const int ECHO_PIN = 11;
const int TRIG_PIN = 12;

LedControl lc = LedControl(DATA_PIN, CLOCK_PIN, LOAD_PIN, 1);

int getDistance() {
  // send trigger
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  // calculate distance
  float duration = pulseIn(ECHO_PIN, HIGH);
  float distance = (duration * .0343) / 2;
  // return distance as an integer
  return (int)(distance + 0.5);
}

void setup() {
  Serial.begin(115200);
  pinMode(ECHO_PIN, INPUT);
  pinMode(TRIG_PIN, OUTPUT);
  // initialize MAX72xx
  lc.shutdown(0, false);
  lc.setIntensity(0, 8);
  lc.clearDisplay(0);
}

void loop() {
  int val = 0;

  int dist = getDistance();
  int mapDist = map(dist, 0, 400, 7, 0);

  for (int i = 0; i < 8; i++) {
    if (mapDist < i) {
      lc.setColumn(0, i, 0x0);
    } else  {
      switch (i)  {
        case 0: val = 0x18; break;
        case 1: val = 0x18; break;
        case 2: val = 0x3C; break;
        case 3: val = 0x3C; break;
        case 4: val = 0x7E; break;
        case 5: val = 0x7E; break;
        case 6: val = 0xFF; break;
        case 7: val = 0xFF; break;
        default: break;
      }
      lc.setColumn(0, i, val);
    }
  }
  Serial.print("Distance: ");
  Serial.println(dist);
  delay(100);
}