Copyright (c) 2018 Boot&Work Corp., S.L. All rights reserved
  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  GNU Lesser General Public License for more details.
  You should have received a copy of the GNU Lesser General Public License
  along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
////////////////////////////////////////////////////////////
volatile int counter = 0;
void setup() {
  Serial.begin(9600L);
  attachInterrupt(digitalPinToInterrupt(I0_5), count, RISING);
  Serial.println('Hall Effect Sensor started');
}
////////////////////////////////////////////////////////////
void loop() {
 Serial.println(counter);
 delay(1000);Â
}
void count() {
 counter+=1;
}