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Exercise 2.1 - Lights and Buttons

f) Sequence of colors

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

Press the RGB LED button (hardware) to change the LED's color in a sequence from white, yellow, green, blue, and red with every click of the button.

script.js

This is the JavaScript code behind the above application.

/* global writeLog, getInput, tf */
writeLog("Solution for exercise 2.1 g) Sequence of colors");
// Create a global variable to store the found devices
var devices;
var led;
var button;
// A list with the color sequence
var colorSequence = [
 { "r": 255, "g": 255, "b": 255 },
 { "r": 255, "g": 255, "b": 0 },
 { "r": 0, "g": 255, "b": 0 },
 { "r": 0, "g": 0, "b": 255 },
 { "r": 255, "g": 0, "b": 0 }
]
var index = 0;
// 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 LED light
 led = devices.getDeviceByIdentifier(271);
// Get the LED button
 button = devices.getDeviceByIdentifier(282);
// Turn both LEDs off initially
 led.off();
 button.off();
// Get notified when the button is pressedn
 button.registerListener(buttonPressed);
}
function buttonPressed(buttonEvent) {
 var buttonState = buttonEvent.getValue("button_state");
// When the state is RELEASED, the button must have been pressed before
 if (buttonState === "RELEASED") {
// Get the next color from the sequence
 var nextColor = colorSequence[index];
 writeLog(nextColor);
 led.setColor(nextColor.r, nextColor.g, nextColor.b);
// Increase the position in the sequence
 index++;
// Check whether we are at the end of the sequence
 // Start over if yes
 if (index >= colorSequence.length)
 index = 0;
 }
}