Nuts and Volts - January 2009

Use the tools you already have on hand

Surface mount soldering

BY ROBERT L. DOERR

Some people tend to shy away from using surface mount components in their projects. It seems to be too difficult or needs an array of specialized equipment. In the past, I found myself in this same mindset — wary of using these types of parts. That all changed when I got involved with an open source motor controller project (OSMC). It used a mix of surface mount and through-hole components. I took the plunge and built up a pair of OSMC H-bridge boards and the MOB (Modular OSMC Brain) controller board which I used in the Battlebot Crash Test Junior. At the time, there was little information available on how to mount these parts using an ordinary soldering station and tools that most hobbyists would have on hand. Not wanting to invest in a whole new set of tools (hot air stations, etc.), I experimented a bit and used common sense techniques to get the job done. A point I'd like to stress is the myth about requiring anything exotic to work with most surface -mount parts. I don't own or use any special soldering equipment for this. All of the soldering that I've done on surface mount boards is built with an old Weller WTCPT station and TC201 soldering iron. It has the fine tip that came standard on it. If you happen to have access to specialized tools, go ahead and use them ■ Surface mount resistors between pads on a but you still may find these

protoboard.

■ Adding extra capacitors between pins.

tips helpful. It has been my experience that depending upon your techniques, you can get by just fine in most instances without specialized tools. The techniques and methodology you use when initially assembling a project using surface mount parts can make all the difference! It takes a little getting used to but quickly becomes second nature. It does require good eyesight (or a big magnifying glass) and a steady hand though. Now, if you start talking about parts that use a ball grid array (BGA) connection or others like that then you would need special tools. Careful selection of parts to avoid difficult package styles can make using tools most people already have on their bench a viable option.