#include <CapacitiveSensor.h>

CapacitiveSensor pads[] = {
  { 2, 3 }, { 2, 4 }, { 2, 5 }, { 2, 6 },
  { 2, 7 }, { 2, 8 }, { 2, 9 }, { 2, 10 },
  { 2, 11 }, { 2, 12 },
};
#define array_len(a) (sizeof(a) / sizeof *(a))

void setup() {
  Serial.begin(9600);
  Serial.println();
  pinMode(13, OUTPUT);
}

unsigned long last_touch_time[array_len(pads)] = {};

void loop() {
  unsigned long start = millis();

  int last_touched = -1;
  for (int i = 0; i < array_len(pads); ++i) {
    long val = pads[i].capacitiveSensor(30);
    bool current = val > 200;
    if (current) {
      if (last_touch_time[i] == 0) {
        last_touch_time[i] = millis();
      }
      if (last_touched < 0 || last_touch_time[last_touched] < last_touch_time[i]) {
        last_touched = i;
      } 
    } else {
      last_touch_time[i] = 0;
    }
    Serial.print(val);
    Serial.print(" ");
  }

  // print each value of the pads the print the last touched pad
  // and the processing time, separated by space

  unsigned long processing_time = millis() - start;
  Serial.print(last_touched);
  Serial.print(" ");
  Serial.print(processing_time);
  Serial.print("\n");
}