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Exercise 2.2 - Sensors

a) Read the temperature

This is the console. All output created with writeLog() is shown here.

Press the button to start reading the temperature information.

script.js

This is the JavaScript code behind the above application.

/* global writeLog, getInput, tf */
writeLog("Solution for exercise 2.2 a) Read the temperature");
// Create a global variable to store the found devices
var devices;
var temperatureSensor;
// Initialite connected devices
tf.initDevices(initDone);
// Call this when all connections are established
function initDone(connectedDevices) {
if (connectedDevices.length === 0) {
 writeLog("Oops, didn't find any devices! Make sure they are connected and refresh this page!");
 }
// Store the devices on the global variable
 devices = connectedDevices;
// Get the humidty sensor (includes temperature)
 temperatureSensor = devices.getDeviceByIdentifier(283);
}
function startReadingTemperature() {
 writeLog("Start to read the temperature.")
 temperatureSensor.listen(temperatureChanged);
 temperatureSensor.setCallbackInterval(5000);
}
function temperatureChanged(event) {
 var temperature = event.getValue("temperature");
// If the value is a humidity value, then getValue() returns null
 if(temperature !== null) {
 writeLog(temperature);
 }
}