new_contents: var j5 = require('johnny-five'),
      HI = require('heat-index'),
      arduino = new j5.Board(),
      COMMAND = {
          TH: {
              GET: 'TH:get'
          },
          AC: {
              TOGGLE: 'AC:toggle'
          }
      };
  
  // SysEx STRING_DATA handler
  function onString(data) {
      var response = parseStringMessage(data);
      if (response.type === 'XX') {
          console.log(data);
          return;
      }
      if (response.type === 'TH') {
          console.log(response)
      } else if (response.type === 'AC') {
          arduino.emit('AC:toggled', response);
      }
  }
  
  // format string data to object
  function parseStringMessage(data) {
      var response = {
          type : data.split(':', 2)[0],
          body : data.split(':', 2)[1]
      };
      if (response.type === 'TH') {
          response.temperature = parseFloat(response.body.split(',', 2)[0]);
          response.humidity = parseFloat(response.body.split(',', 2)[1]);
          response.heatIndex = HI.heatIndex(response);
      }
      return response;
  }
  
  // send Temperature and Humidity request to Arduino
  function requestTemperatureHumidity() {
      if (! arduino.io) {
          console.error('not connected to arduino.');
          return;
      }
      arduino.io.sendString(COMMAND.TH.GET);
      console.log('to arduino: sent TH request');
  }
  
  arduino.on('ready', function () {
      arduino.on('string', function (data) {
          onString(data);
      });
      setInterval(requestTemperatureHumidity, 1000);
  });
  
subject: print temperature and humidity.