Check out http://ecomodder.com/forum/open-revolt-open-source-dc-motor-controller.html
if you want to read about the whole story!
Experience in soldering is important. If you want to really keep costs down, a mill is helpful, but that work can be outsourced to a local metal shop.
Step 1: Get/Make a power board and control board.
You could print the picture from this link and somehow transfer it onto a piece of heavy blank PCB, and etch it with a dremel if you have a ver y steady hand. The dimensions are 8"x6". This link also has the G-code that you can use to etch with a CNC mill or you could give the G-code to a machine shop.
Picture 2 and 3 below is an example of an early power board I made with a Dremel.
You can get a control board from me or you can make the control board in your favorite PCB layout software using the schematic here::
And here are some pictures of the PCB layers:
A predone control board is Picture 1.
Pictures 7 and 8 are the power board top and bottom. The 8 solder spots are just where vias were added.
Once you have the 2 boards, you can go to step 2.
Step 2: Drill your metals and isolation strips
1/4" x 3/4" x 12" C110 copper bar.
Two 3/16" x 3/4" x 10" C110 copper bars.
3/4" x 1.5" x 8" aluminum bar.
3/8" x 8" x 11" aluminum plate.
3/16" x 3/4" x 8" steel bar.
Two 1/16" x 3/4" x 8" unclad FR4 used in making PCB.
1/16" x 6" x 8" unclad FR4 board.
5/16" drill bit (or 3/8" drill bit if you need slop)
1/8" drill bit.
3/16" drill bit. (Must allow a #6 screw to fit through)
Do all the drilling! It may help to take the big aluminum bar to a machine shop, since it's not easy drilling through 1.5" of aluminum accurately. See all the pictures below for notes on hole locations and drill bit sizes.
Here's a video on how the power section pieces all get bolted together, without the electronics attached, just so you can see how it all fits:
Step 3: Order the electronic components
And order these components for the power section. If you have already bought and drilled the metals on step 2, then don't reorder them. They are listed here as well.
Step 4: Solder the control board
45 or 60 watt soldering iron.
0.032" diameter (or so) rosin core solder
This step takes about 3 or 4 hours. It's very unforgiving. If you have never soldered before, you should get help with this. The ground plane doesn't have "thermals", so it takes some heat to melt the solder to it. Check out this help file for soldering the control board. See pages 2 through 19:
Watch for solder bridges (when big globs of solder bridge isolation gaps). Also, you may want to socket the ATMega168. You can program the ATMega168 in-system. So, you can solder it in, and then program it if you want to. Or you can get one preprogrammed.
This video walks you through soldering the control board from start to finish:
Step 5: Program the ATMega168 Microcontroller
You can make a very cheap ATMega168 programmer, or buy an AVRISP MK2:
And download the free AVR Studio development environment:
The hex file of the code is available here. Use "coug-unified-16k.hex":
Here's the code:
The fuse bits are Extended High Low = F8 DC F7. But if you are using Ponyprog, the fuse bits are 08 DC F7.
If you don't want to bother to program it yourself, then you can buy a preprogrammed one.
Step 6: Assemble the Power Section
Step 7: Mount the control section to the power section
You can also check out pages 44-46 of the help file here:
Get Ready!!! There's only one more step!
Step 8: Drive Away!!!
And here's a video of Joe in Phoenix using that same controller at 144v:
Now go out and build one! Doing it yourself can save you over $1000.