Sunday, 26 January 2014

Getting known with Arduino

This year started with an interesting new course that is all about building a prototype. I have always found robots fascinating and now I have an opportunity to build something with my own hands.

The very first project - traffic light controller

Our first assignment was to build a small project from the following components:
  1. Arduino (UNO) and USB
  2. Jumper wires
  3. Led lights
  4. Breadboard

1. Hello world, can you hear me?

I downloaded the programming environment for Arduino from (My operation system is Windows 8.1). 

Once the software is installed it is necessary to test if the Arduino is responding to it by blinking a light, in other words this is Arduino's way to say "Hello World".
Connect Arduino to your computer with USB and open the programming environment. Choose File > Examples > 01.Basics and run it. If everything is fine Arduino will now blink it's led. Just to be sure I changed the running loop's delay times to see the resorts in action before going any further.

2. Testing the led light

I like to build everything in small steps. Instead of trying to attach all the led lights on the breadboard at once I start with one.

Led has two legs - the shorter one is "negative" and the longer one "positive". This must be remembered when connecting the jumper wires between Arduino and breadboard.

For example I connected one jumper wire on the gnd pin of Arduino and put the other end vertically to the same line where I had attached my negative leg of the led light (GND > J61). After that I connected the other jumper wire between LED light pin 13 and other end vertically to the same row on breadboard where the positive side of the led leg was attached. I ran the Arduine Blink code again and the little miracle happened - the green led light started blinking!

3. The final result

I attached the second led light with the same method as I did the first one but this time I had to connected the ground wire differently. I put it through the the same row where the first (green) led's negative leg was to the second's (yellow) negative leg row. The lights worked but in order to make them some short of traffic light I needed to change the code - When the green light is on the road is free to go for 2 minutes. When the light is off there is still two minutes time to use the road until the users of the "yellow" road are allowed to drive.

Based on the prototype course by Tero Karvinen (
and the book - Karvinen 2011: Make Arduino Bots and Gadgets