Jason Rollette's
Hackaday.com contest entry
MEGA32 programmer and dev board.
I started this project simply to enter the Hackaday Design Contest When I saw this contest I thought it more fun than anything and I also found it a great opportunity to design a useful board for others, with the recent knowledge I had gained in building my ROVRev2 project ROV.
I put stricter criteria on my design than what the contest rules stated to keep the design simple, and something that could be made by any of the readers. My board can be build single side only, with only a few jumpers this would allow many to make their own boards using an etch process. I also wanted to stay through hole because of many people’s quandaries about this technology at home. One other goal was to keep the parts count low I used only 21 different parts , this would make the possibility of providing kits easier. I also wanted to make the most capable board possible in the space allotted. I could have easily put a smaller processor, and used only a fraction of the board. But why not make it challenging! All of this added difficulty to the board design, but I thought it better for the community in the end.
The board I designed is a simple micro controller Development board that could be built for under 35 dollars. The board is based on an Atmel Mega32 40 pin dip. I chose this processor because it can be programmed in BASIC or C++ with software that is free or open source.
Here it is the board partly asembled, but you can see how I tried to use every availible space.
This is the basic board layout, I tired to keep it sigle sided so anyone can etch the board.
The schematic is done in ExpressPCB which is a free download.Schematic
Here is the Bill of Material and pricing for the all the parts.
My first goal was to keep it single sided so you could etch the board your self on copper clad.
I follow these steps when doing so.
Materials: Muratic acid, common household peroxide, safety goggles, good quality magazine, laser printer, plastic contain the board will fit in, plastic brush, clothes iron, lacquer thinner, rubber gloves, paper towel
1. Print the bottom side layer on high quality magazine (thicker and shinier the paper the better)
2. empty an water out of the clothes iron, and put iron on hottest setting.
3. align printing on to copper clad board. (printing facing copper)
4. find hard flat heat resistant surface, firmly press iron on to magazine paper on to copper clad ( do not move iron for 1 min) push hard!
5. then for 4 more min slow move iron around on paper and board making sure to put a lot of pressure on the on the paper. When done let cool
6. put board in cold water let soak for 5 mins, try to peel paper from board leaving only the print from your laser printer. The toner should then be stuck to the copper.
7. If not use lacquer thinner and paper towel to clean toner from copper board and start over. If the traces look good then move on.
8. Mix 1 cup muratic acid, and 2 cups hydrogen peroxide in plastic container. ( wear goggles, gloves, and don’t breath fumes)
9. put in copper clad board with copper side facing up. Use plastic brush to gently wipe the board. You will notice the copper begin to dissolve. It takes about 3-4 mins to get all the copper dissolved. You just have to watch to make sure it is gone in all areas between traces. Do not leave it in for a long time as the traces will dissolve under the toner if left too long. ( don’t do this in a stainless steel sink)
10. Take board out of solution, inspect to see if all copper is dissolved if so run under water for 3 mins and wash clean. Then dry with towel.
11. The solution is pretty much used up at this point because of all the copper dissolved in it. I dispose of it by diluting it in five gallon pale of water. (it is pretty much harmless at this point)
12. Use lacquer thinner, and paper towel to remover toner left on top of copper traces. Carefully inspect board traces.
13. You can tin all the trace with solder and a solder iron if you want. ( this actually makes drilling easier)
14. Drill all the holes for the parts.
15. Print out topside silk screen layer on paper and iron that on the top side. Using same process as above. Run under water and peel off paper. Now you have component ID’s on the top side.
I designed my board in EXPRESSPCB it can be downloaded here. http://www.expresspcb.com/ it is a free program and is easy to learn if you are not good at this sort of thing and are normally a pref/proto board person I recommend it! You will see how easy the board can be modified and changed to fit your need. They also offer the option to build the boards for you at a reasonable cost if you don’t care to do the etch your own method.
To begin programming the AVR you need to download and install BASCOM http://www.mcselec.com/
Hook the board to your parallel port, turn on power to the board.
Create or load in a program click the compile current program button then the Program button. If everything is working it will display an ATMEGA32 as your chip and you are ready to go.
The first time you program an AVR you need to set a couple Lock and Fuse bit options that throw off a new user! I took a screen shot to help eliminate confusion. Once you make the changes to match the screen shot click the write FSH and FSE buttons. Then go back to the Flash ROM tab and program your chip.
Using the green button at the top.
Email Me with other questions