Updated arduino-light code

arduino-light.js

var mqtt = require('sc-mqtt'),
    slash = require('slash'),
    client = mqtt.client('tcp://localhost:1883','sc-ard-light'),
    preDawn = 22000,
    JavaString = java.lang.String;
  
client.connect();
client.subscribe('arduino-light');
var max = 0;
function updateTime(topic, message){
  var val = +(new JavaString(message.payload));
  if (val > max && (val - max < 10)){
    max = val;
  }
  var rawTime = preDawn + (val * (8000/max));
  var time = Math.floor(rawTime % 24000);
  slash('time set ' + time , server);
}
client.onMessageArrived(updateTime);