When you're building a system, you need parts. I try my best to scrounge, reuse, recycle, and salvage most of my parts, but I usually have to order something or other to get the job done. This time, the project is an art show I have in April. The basic concept is taking magnetic stripe cards (like credit cards and hotel key-cards) and re-interpret the data into light and sound.
The parts in these posts come from two of my favorite suppliers - The Maker Shed and Sparkfun. The Maker Shed is geared a little more toward kits, learning materials, and extras (shirts, tools, etc.), while Sparkfun has more nuts-and-bolts type items like specialized sensors, chips, and displays.
The first device you see there is called the Arduino. The Arduino is a great open source development board for programming microcontrollers. It uses the ATMEGA 328 chip (see below) and facilitates programming, development, and prototyping. Cost:$35
Breadboards allow rapid prototyping of electronics without committing to a single design. You can sort of think of it as a big Lego plate, and the sensors and wires as smaller Legos. You can plug in different wire and attach different devices until you're happy with you're design. From there, usually you solder all of your parts onto a circuit board, but with a board as small and cheap as this, you can keep alot of projects on it. Cost:$5
These wires are designed to work with breadboards because they have pins attached to each end. This is very handy for connecting small parts or multiple breadboards.Cost:$7
Here we have an LED matrix. Each of these LEDs can be controlled individually to display graphics. I'm using this as a prototype to implement Conway's Game of Life. The device will use the data from a magnetic card to start the game. Eventually I want a very big display, but this mini one will help me design the system first. Cost:$6
The Ping sensor is actually going to be used for another project for a friend. This sensor is ultrasonic, and can determine an objects distance from the sensor. Just like a bat, the sensor sends out an ultrasonic sound burst, and counts the time it takes for the sound to bounce back. This sensor is often use to help robots avoid obstacles. I'm going to use it to create a proximity sensor, that will change the speed of glowing lights based on your proximity to them. Cost:$35
Here we have the brains of the operation. The ATMEGA 328 is a microcontroller that is capable of being programmed to carry out a variety of tasks. It has been used in everything from robots to Unmanned aerial vehicles, from heavy duty farm equipment to devices that generate TV signals. The small silver piece next to it is a crystal oscillator. This device is the "clock" required to run the microcontroller. This device runs at 16 MHz. Compare that to the 2-4 GHz running your computer! Cost:$5 per chip, $1 per oscillator
Ah, the card reader. You can build your own card reader out of an old walkman and a linux computer, but this solution is a little more robust. This device will read just about any card out there, then send the data as a stream that a computer or a microcontroller can read. Cost:$60
I plan to keep everyone posted on my progress with this projects. It's going to be great! Post any questions/comments below.