Assembling the motor controllers

It's called the "Open Source Motor Controller", or OSMC for short. It was created by a company that's actually local to me, called Robot Power. As you can see from the picture above, it's dated late 2001, during the short lived "BattleBots" era. Thanks to it's open source design and basic off the shelf components, it's still around 10 years later, and still a very viable option for high current motor control. According to the Robot Power website, it's good for 160amps continuous, and 400amps peak/surge current. That's pretty freaking epic, given how cheap it sells for compared to other motor controllers.

You can buy these pre-assembled for a very fair price, but if you're a true tightwad like I happen to be, you'll want to buy the bare boards, then buy the components yourself and solder them together yourself. I omitted a few components in order to save a couple bucks while I was at it, as well. The picture above shows the SMT components that get installed first. I had never really soldered SMT components before. I have moved SMT resistors around on computers before to overclock, but never actually done it properly and on a new board. After having done this, I feel MUCH more confident about doing it again in the future. It went really well. In order to do it, I bought a 1.2mm wide chisel tip for my soldering iron (it uses Hakko style tips), .025" wide solder, and some needle nose plier designed for SMT soldering. The components are 0603, which is pretty much the largest SMT size, and the solder pads are oversized, which makes it very very easy to do. I didn't use magnification, just lots of light (100 watts of CFL lights, it was so bright it almost hurt.. hahaha). Turned out quite well. 

Next up were the through-hole components. It started with diodes, and I quickly ran into a problem. Many of the solder pads are just flat part of the ground/power plane on this board. The copper on this board is very thick, and it covers half the board. Even turned all the way up, I couldn't get enough heat from my normal soldering station. So I went out to the garage and grabbed something I thought I'd never use on a circuit board, ever.

It's a 180watt equivalent Butane powered soldering gun. I used to use this at work to solder alarm system power wires to 4 gauge battery cables in cars and heavy equipment. It's seriously hot. It does the trick nicely with this board, pretty well the moment it achieves proper contact with the board (that MASSIVE tip is a PITA, it's like 12mm x 4mm or so.

Two action shots with me using that monster of a soldering iron.

More to come when I finish installing the components.

© Una 2011