Haha... at least give him a chance to actually TEST the thing before we start buying stuff! A big bonus of going this route is the ability to get double sided 4oz copper. This makes the whole board a pretty decent heat sink, and allows for plated vias for very strong solder connections. I'm very worried that Paul's "surface mount" soldering will rip off when it gets heated and vibrated.
We'll see about getting some PCB gurus to really go over the design when done. There are some really fancy tricks that can be done to reduce heat and noise in pcb design that takes years of experience to figure out. When Paul's car pulls back into the driveway from his first trip to the gas station (to inflate his tires, of course), then we'll start to revamp his design, THEN buy a bunch of boards.
Just learned about this thread yesterday (e-mail about the competition), I voted your project straight away, and then settled in to read it. (while the paint dried, between coats)
Just finished. I must say I had to fight the urge to knee-jerk respond to problems you faced a year ago!
I have some Atmega8-16PUs already, I wish I could hack up something with some of the computer/DVD/Radio Control circuits I have . Just enough to run the motor from a kids plastic 4-wheeler off of a car battery .
I would almost be more interested in an AC version of this (and some sort of open-source motor that could be built with it.) My thoughts go toward wheel motors made from large alternators (I just hate the idea of drive-shafts and a transmission adding weight and wasting space for batteries).
I am keen to see what happens, if this is feasible and can be made cheaper/mass-producible once the R&D is done.
I connected the heat spreader to the M- bus bar with JB weld (with some space between them too) and connected the mosfet/diode clamps. Those clamps push with like 25 or 30 pounds I think. They are designed just for these specific TO-247 type of packages.
I finally found a good way to cut plexiglass. We bought an attachment to the dremel. I also bought a small piece of Lexan to finish the box, and it is way easier to work with! I might be able to trim down the size of the box some. Version 2 can be quite a bit smaller. This box is just a temporary thing to hold everything. I should finish the box this weekend.
I'm almost done with the control board. I also have a nice new big breadboard! Plenty of room!
motor_control: I haven't uploaded the software yet because it is undergoing dramatic changes.
__________________ As I watch the old man walk on the sidewalk below my window, I think "Some day old man, I will be like you. So why not give me your coat?" Then I go downstairs to get his coat, but he's gone. Hey, maybe he was Zorro.
Beauty and the Beast.... you need a PCB for that control unit!
If you were able to use double-sided PCB for the power board, would that have made it easier? I see that you have two single-sided pcb's put together and some holes running through with resistors popping out...
Do you know how much space there will be for the controller? Your help will be coming soon! With all your fancy video equipment, and mad scientist/experimenter tendencies I can think of no better person to test this thing out!
P.S.: I finally got that stupid input and output (not the analog to digital converters) stuff working on the micro-controller. Now I will be able to monitor when the hardware shuts off the mosfets and I'll be able to send a pulse to reset the hardware overcurrent events, turning the PWM back on. Stupid Pin, Port, DDR! Makes me mad!
-Paul
__________________ As I watch the old man walk on the sidewalk below my window, I think "Some day old man, I will be like you. So why not give me your coat?" Then I go downstairs to get his coat, but he's gone. Hey, maybe he was Zorro.
Ya, I was talking about the room in the car. The box with the heatsink and control section was a bit bigger than I was expecting.
I attached the software which is just a draft. Pieces of it have been tested, but not all of it at the same time. I think I will test it on the bike controller.
It should be renamed .c instead of .txt for the extension of the file name.
-Paul
__________________ As I watch the old man walk on the sidewalk below my window, I think "Some day old man, I will be like you. So why not give me your coat?" Then I go downstairs to get his coat, but he's gone. Hey, maybe he was Zorro.
. Just enough to run the motor from a kids plastic 4-wheeler off of a car battery 
.
