Blink an LED
Overview
In this tutorial you will learn how to create a simple circuit, access Cloud9 (the BeagleBone's coding interface), load and run a script. When you run the script the LED will blink. By editing the code you can then change the brightness and frequency at which the LED blinks.Note: This tutorial uses a BeagleBone set up specifically for our BeagleBone Black Tinkerer Workshop. The BeagleBone Black you will use in the Tinkerer Workshop will be set up with a Display and a Keyboard with a trackball mouse, and the JavaScript Files will be saved to the board. The BeagleBone will be running Angstrom, which come pre-loaded when you get the board. If you are not in a Tinkerer Workshop and want to do these projects, you can find a guide on how to attach a keyboard with a trackball mouse and a display here. You will also need to add the JavaScript files, which can be found here, to the following directory on the BeagleBone Black: /var/lib/cloud9/workshop
Parts List
- 1x BeagleBone Black Board
- 1x Medium Breadboard
- 1x Jumper Wire Pack for Breadboards
- 1x Red LED (Available in the Prototyping Parts Kit)
- 1x 330 Ohm Resistor (Also available in the Prototyping Parts Kit)
Wiring Diagram
Step 1
Wire the components as shown. The LED only works connected one way (longer lead wire is + )Note: The resistor is required to limit the current to the LED.
Step 2
Plug the DC power jack into the BeagleBone Black to power the device.Step 3
Once the system is ready, click on BEAGLEBONE-workshop icon to open the Chromium browser and then start the Cloud9 IDE BeagleBone.local:3000 (192.168.7.2:3000)Step 4
In the Cloud9 workshop folder click on the file Project1.js to open the BoneScript program that will control the LED and make it blink.The code should look like this:
var b = require('bonescript');
var ledPin = "P8_14";
var state = b.LOW;
b.pinMode(ledPin, b.OUTPUT);
b.digitalWrite(ledPin, state);
setInterval(toggleLed, 500);
function toggleLed() {
if(state == b.LOW) state = b.HIGH;
else state = b.LOW;
b.digitalWrite(ledPin, state);
}
In the Cloud9 workshop folder click on the file Project1.js to open the BoneScript program that will control the LED and make it blink.Step 5
Now press Run at the top of the Cloud9 interface. If this says "Debug", select "Run" from the drop down under this button.
