Fun with 8×8 LED Matrix

I’ve finally got around to wiring up my 8×8 LED Matrix and now it’s time for some fun with it. Though out playing with this I’ve learnt about shift registers and how we can use them along with a transistor array chip.

First things first, have a read and look through the Arduino’s ShiftOut guide as they are very well put together (keep re-reading it if it doesn’t make sense): http://www.arduino.cc/en/Tutorial/ShiftOut

To summarise the guide:

• A shift register allows you to have 8 outputs while only using 3 pins on the Arduino
• You send a byte to the shift register which has 8 bits (e.g. 10010000)
• You can combine shift registers so instead of having only 8 outputs you can have 16 when using 2, 24 when using 3, and so on
• When combining shift registers, instead of sending out the 8 bits to the first register and 8 to the second register it’s actually reversed, so the first 8 bits you send are actually for the second register and the next 8 bits go to the first register

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Building a Small Robot: Part 4 – Using Senses For Control

We know how to control our 2 motors in both directions and we also know how to use our Phototransistors to detect if an object is close, now we put both of these together to form our robot. In this part we focus more on producing the code as we’ve already put our robot together as below.

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Building a Small Robot: Part 3 – Sensing Walls

So we’ve got our robot moving in different directions and now we need it to move to the directions we want which is away from walls. We do this using Phototransistors which is sort of similar to a Light Dependent Resistor (a component that changes resistance due to lighting) except Phototransistors actually use infra-red and have two components, the emitter and detector. The emitter well emits the infra-red (which we can’t see) and the detector detects how much of that infra-red is coming back.

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Building a Small Robot: Part 2 – Moving Forward

So we’ve got our parts and our motor controller so we are now ready to make this robot move forward, backwards and turn. I’m assuming you’ve put the wheels on the motors, mounted them to your design, used a gearbox if necessary and you do have a motor controller. Plus you also have the 9 volt battery and clip for Arduino.

In this part we will need:

• Arduino Duemilanove ATmega328
• 4 x NPN general transistors (e.g. PN100, PN2222)
• 4 x 6.2K Ohm resistors (10K will do fine too)
• Breadboard
• Some wire

Example Schematic below

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Building a Small Robot: Part 1 – Parts required

I’ve decided to make the next project that just about every person exploring electronics does… the making of a small robot. In my case, I’ll be using the Arduino to control the robot which will just be a robot that can avoid walls that  I might build more functionality in the future.

The first part of the project is to acquire the necessary parts such as motors, gears, wheels, infrared sensors, etc. Luckily for me, I actually had a robot that I was building up before; it’s the Cycbot from RealRobots (for anyone who might remember it). I got around to issue 6 or 7 and eventually gave up on it. I do however have the motors, gears, wheels and the motor controller, so it’s all actually working, it just goes forward for now.

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Arduino Project: LCD Road Runner

So I’m very interested in electronics again and I bought the Arduino Starter Kit from a supplier in Australia and I’ve been testing it out a bit. I also bought an 16×2 LCD, a 8×8 LED Matrix and some other parts too.

I’m always trying to make games out of everything so naturally I started thinking of games that can be made using the LCD and came up with a car type game which you try to avoid walls and shot enemies blocking your path. This game would be better if you have a 20×4 LCD as just having 2 positions to change to is kind of limiting the game experience.

LCD Road Runner
v0.1 (10 April 2010) – Initial Release with 10 levels

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