UPDATE 2!! Code is ONLINE!
This project details my rather rapid build of a 24x8 matrix.
My inspiration for this project came from Syst3mX's 24x6 matrix. A 24x6 matrix was huge, but it just was too small for me, as not much can be done in only 6 lines. My goal was to increase the line count on that display, so I could have a few extra pixels.
Basically this is just a 24x8 matrix with a cool, interlocking foamboard grid that makes it possible to have a really big display. This display is 3 feet long, and just over a foot high! Thats half the size of a large, flatscreen TV! Plus, the whole thing is arduino controlled, so you can program it to do other cool things, besides just showing text! :)
I am just also a high school student, and i love to make stuff. So would you consider voting for this project in the current contests? Thanks!
Difficulty: This project will be pretty simple for an expert, but a beginner will struggle with it. Better for those who have had some experience with soldering/building circuits.
Cost: The entire project can be done for less than $70, much less if you already have an arduino board.
Time: 2 weekends or about 1 full season of Star Trek's work.
Step 1: Materials
• 192 LEDs (LEDs can fail or be fried easily, so I recommend getting 200 even)
• 3 x 74HC595 shift registers
• 24 resistors (Use this to get the values you need (http://led.linear1.org/1led.wiz), you will have to know your LEDs forward voltage and current, as well as what you are supplying it with (in the case of arduino it is usually 5v sourced))
• 8 x 1k resistors
• 8 x 2N3904 transistors
• 1 x 4017 decade counter
• 1 x Arduino board or Atmega 328 chip. Make sure you have the tools to program it if you just have the chip
• Wire (lots of it!). I went through probably 50ft of wire making this. At least 50ft, if not more...
(A side note on the wire, solid core wire in a thin gauge (22-26ish), is very helpful when building this, because we will strip most of the coating of to solder it. If you can find some uncoated wire, that will help for most of the building process, and save you lots of time stripping wire)
• Tracing (sketching) paper. You can also use wax paper or parchment paper if you cannot find tracing paper
• Glue. I just used white Elmers glue and it worked great
• A foamboard panel (36 in long). I used this board from walmart, its just the right size. They had it in single-piece packages and were in the school supplies. Alternatively, you can use cardboard, or a similar type of board.
• Electrical tape (optional, but really useful)
Shameless plug- I get most of my parts from taydaelectronics.com- great store (especially for students on a budget :D), but shipping takes a while (~10 days). If you want to get it quick, I recommend Digikey or Mouser electronics. Great stores, and digikey usually gets to me in 2 days.