Thursday, September 20, 2012

I try to get out, but they just pull me back in...

The FSAE team wanted to resurrect the 2012 failcar to show off during Cooper Union's annual Fall Festival as a way to lure in unsuspecting freshmen to join the team. One of the major problems in realizing that dream is that the power distribution on the car utterly sucked and probably doesn't work anymore. So, like any respectable engineer, I decided that I could make a new system from scratch that would be better in every way possible. Since I'm not actively participating this year (wait, I guess this is the first time I mentioned that?), I also decided that this project would be a good segue for the next person in charge of the engine and electrical subsystems.

Here is the product of about three days of work:
The schematic. Ain't it pretty? I taught my protégé the fine art of mitering everything so that it looks professional. Ignore the crossed wires though...
Here's the board. The huge traces are because it's rated for automotive things -- 15A pumps, 15A fans, etc. The big rectangular blocks at the sides are kickass solderable lug terminals. The connector at the bottom is a 35-pin right angle ampseal connector.

Since everything had to get done in less than two weeks (and really in the last three days...), we milled the board in-house on 1/2 oz one-sided copper clad using a 1/32" endmill, which is why the trace clearances are so big on the board. I can't decide if this is a stupid and abusive way to use our expensive CNC mill or only just stupid. There are a couple of designed-in flywires on the board since there was literally no way to put more fat traces on the top layer.

Actual board pictures are forthcoming once I get off my butt and take them. The amount of solder I laid on the traces is amusingly stupendous.

Here are the pictures:
The copper side of the board. Look at those huge blobs of solder! The flywires  are some conduction paths that wouldn't fit on the board. The rectangular bits poking out on the right are the lug slots.

Topside. Looks pretty neat...

Tall, dark, and handsome. Enjoys long walks on the beach and switching motor loads.

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