Step 1: Getting All The Right Things So you will need the basic set of tools for this project : a soldering iron, some solder wire, a cutter, a needle nosed plier,some wire, wire striper, and some desoldering tools if you need them. For the matrix you will: 1. 144 LEDs 2. 24 resistors( The value is determent by the type of LEDs, in my case 91 ohm) 3. 4017 decade counter 4. 6 1KOhm resistors 5. 6 2N3904 transistors 6. A long Perfboard 7. Arduino 8. 3 x 74HC595 shift register 10. some pin headers
Step 2: How it works? The tricky behind the display is multiplexing and the idea is the same as withe the 8x10 LED matrix: It is basically a way to split information in to little peaces and send it one by one. this way you can save a lot of pins on the Arduino and keep your program quite simple. Now this time we have 3 shift registers which multiply the number of outputs and save lots of arduino pins. Each shift register has 8 outputs and you only need 3 arduino pins to control almost an limited numbers of shift registers. We also use the 4017 decade counter to scan the rows, and you can scan up to 10 rows with it because you have only 10 outputs but to control it you need only 2 pins. The 4017 is a very useful chip and it's a good idea to know how to work with it(http://www.doctronics.co.uk/4017.htm ) Like I said the scanning is done with the 4017, by connecting one row at a time to ground and sending the right data via the shift registers to the columns.
Image Notes 1. 4017 With 6 transistors for scaning the rows 2. The 3 shift registers to control the rows
http://www.instructables.com/id/20-Unbelievable-Arduino-Projects/