tingbot-node

An unofficial Node.js module to listen for buttons pressed and control backlight brightness on a tingbot-equipped raspberry pi running a configured Raspbian.

Installation

The Tingbot Hardware should already be configured and running – this will not install any drivers or configure your system.

The preinstalled version of Node.js on Raspbian is pretty ancient. Make sure you have installed at least the current stable version including npm.

To get a simple Node.js project, just create a directory for it somewhere, place an index.js in it and run npm init there.

Install tingbot-node first. While wiring-pi installs, you can just keep reading here.

npm install tingbot-node --save

How To…

Use it in your .js file:

var tb = require('tingbot-node');
var tingbot = new tb();

Keep in Mind:

• The Button Module uses wiring-pi – which needs to be run with sufficient user rights to access GPIO – which most likely means running your whole script with sudo, eg. sudo node ./index.js.
• The Backlight Module executes gpio commands via shell using sudo. So you could only use the Backlight module such as this: var tingbot = new tb({modules:['backlight']}); to prevent an error while running without sudo. Default: modules:['backlight', 'buttons']

Buttons

The Buttons Module is available as tingbot.buttons, but normally you should just listen to events fired by it via tingbot.on or tingbot.once. It emits the following events:

• button: Emitted when any Button is pressed or released.
• button#[0-3]: Emitted when Button number [0-3] (from left to right) is pressed or released.
• button-[name]: Emitted when Button [name] is pressed or released. [name] can be left, center-left, center-right, right.
• button-[pin]: Emitted when Button on Pin number [pin] is pressed or released.
• :down: can be appended to only get press events. tingbot.on('button#3:down', function(){})
• :up: can be appended to only get release events. tingbot.on('button-left:up', function(){})

To listen to press/release events on one Button, you'll likely want to access it by name:

tingbot.on('button-center-left', function (data) {
	if (data.direction === 'up') { //do something when the button is released:
		console.log(data.name + ' released:', data);
	}
});

… or by number:

tingbot.on('button#0', function (data) {
	if (data.direction === 'down') { //do something when the button is pressed:
		console.log(data.name + ' pressed:', data);
	}
});

Backlight

The Backlight module is available as tingbot.backlight. Set tingbot.backlight.do_tween = true; for a somewhat smoother brightness change. The module emits the following events via tingbot.on or tingbot.once:

• backlight: Emitted when tingbot-node has finished updating the LCD backlight brightness
• backlight:tween: Emitted at every tweening step if tweening is activated
• backlight:tweendone: Emitted when tweening is finished

tingbot.on('backlight', function(obj) {
	console.log('backlight event:', obj.value);
});

run tingbot.backlight.set_backlight or short tingbot.set_backlight to set brightness

// set backlight value
tingbot.set_backlight(0, function() {
	//does a lot of brightness updates, but can look nice:
	tingbot.backlight.do_tween = true;
	setTimeout(function() {
		//high values will set to maximum
		tingbot.set_backlight(300000);
	}, 1500);
});

More examples:

You could combine both modules to set the backlight brightness when Buttons are pressed. In this example, the outer buttons set the value to minimum/maximum, while pressing the inner buttons de-/increases in steps:

//get all button down events and modify brightness
tingbot.on('button:down', function onBtn(data) {

	var steps = 9,
		range = tingbot.backlight.max_backlight - tingbot.backlight.min_backlight,
		step = range / steps;
	//new values for button pressess:
	var values = [
			tingbot.backlight.min_backlight,
			tingbot.backlight.current_backlight - step,
			tingbot.backlight.current_backlight + step,
			tingbot.backlight.max_backlight
		];

	if (data.number in values) {
		tingbot.set_backlight(values[data.number]);
	}
});

Or just exit the application when pressing both inner buttons for a while, a bit like on tingbot-os:

//check middle buttons pressed for a bit:
var checkTimeout;
var checkFunc = function(cb){
		return tingbot.buttons.buttons[1].isdown &&
			tingbot.buttons.buttons[2].isdown;
}
tingbot.on('button:down', function(btn){
	if([1,2].indexOf(btn.number) >= 0 && checkFunc()) { //only listen for both middle buttons
		clearTimeout(checkTimeout);
		checkTimeout = setTimeout(function dostuff() {
				if(checkFunc()) {
					console.log('middle buttons still pressed!');
					// do something… drastic
					process.exit();
				}
		}, 1200);
	}
})

If you've read all this and didn't find what you were looking for, there's more in the API documentation.