So clearTimeout will throw an error because self.timer is not defined so I defined it as null at the top, and didn’t bother checking if it was null or not before clearing it.

Once this was done we were in the same boat as before with a pir detection of 1 before the timeout has fired resulting in the mirror turning off and on again which is annoying. This is fixed by adding an onstate variable and simply not executing the activatemirror if its already activated. I just moved cleartimeout outside of that check otherwise it won’t work.

My working code below since I find it annoying when people don’t come back when they solve a problem:

// Subclass socketNotificationReceived received.
socketNotificationReceived: function(notification, payload) {
if (notification === ‘CONFIG’ && this.started == false) {
const self = this;
this.config = payload;
self.timer = null;
self.onState = 0;

  //Log.info('PIR: ' + this.name);

  //Setup pins
  this.pir = new Gpio(this.config.sensorPIN, 'in', 'both');

  if (this.config.relayPIN) {
    this.relay = new Gpio(this.config.relayPIN, 'out');
    this.relay.writeSync(this.config.relayOnState);
    exec("/opt/vc/bin/tvservice --preferred && sudo chvt 6 && sudo chvt 7", null);
  }

  //Detected movement
  this.pir.watch(function(err, value) {
    if (value == 1) {
     clearTimeout(self.timer);
    if(self.onState != 1){
      self.sendSocketNotification("USER_PRESENCE", true);
      if (self.config.powerSaving){
        self.activateMonitor();
        self.onState = 1;
      }
      }
     }
    else if (value == 0) {
      if(self.onState != 0){
       self.timer = setTimeout(function(){
          self.sendSocketNotification("USER_PRESENCE", false);
          if (self.config.powerSaving){
            self.deactivateMonitor();
            self.onState = 0;
          }
      }, self.config.offDelay);
      }
    }

});

  this.started = true;

} else if (notification === 'SCREEN_WAKEUP') {
  this.activateMonitor();
}

}

});

1. If the pir watcher detects a change it will run the specified callback from line 55. https://github.com/paviro/MMM-PIR-Sensor/blob/master/node_helper.js#L55

2. If you want to debug the node_helper put console.log(“message”) at the position you want and you will see the message in the terminal.

3. If you change the config in the node_helper, you have to send the changes also to the main module by sending a socketnotification, as you did from the main loop to the node_helper.

4. If you define a callback with function(){…} you switch the scope, so the reference of this is the callback and not longer the node_helper itself, that’s why the author saved this into the variable self upfront. I would personally define a callback as big arrow function () => {…}, the advantage of this is you will stay in the same scope and wouldn’t need a redundant variable.

And I assume you want to use a timeout instead of an interval.

this.pir.watch(function(err, value) {
        if (value == 1) {
          clearTimeout(self.timer);
          self.sendSocketNotification("USER_PRESENCE", true);
          if (self.config.powerSaving){
            self.activateMonitor();
          }
         }
        else if (value == 0) {
          self.timer = setTimeout(function(){
              self.sendSocketNotification("USER_PRESENCE", false);
              if (self.config.powerSaving){
                self.deactivateMonitor();
              }
          }, self.config.offDelay);
        }
});