Friday, 5 August 2011

Guitar PCB boards - SMT rules!

After initial reluctance, we're getting to quite like the idea of using SMT circuit boards for our miniature instruments. True, soldering them can be a bit fiddly - especially with a massive tipped soldering iron - but that can easily be fixed by using a smaller nib.

Even so, with a large tip we've managed to solder some pretty teeny little components.

Another benefit of using SMT is that everything is done on just one side of the board. With through-hole, all the components are on the "top" but on the underside are lots of little spiky bits where the component legs have been soldered to the copper board and trimmed. SMT gives us a nice flat surface on the underside to work with. A bit of double-sided tape on the unused side -

- and the board can be stuck to the acrylic "lid" of the guitar -

- and a nice flush finish, so threading the strings through from the top-side should be a doddle

Compare that to the original design, where getting the strings to line up with the holes, holding everything together AND soldering everything in place was a bit of a nightmare!

In fact, as part of our recent board edits, somehow we've managed to reduce the board length a little bit so the holes on the board don't line up with the holes on the acrylic. They're only a few millimetres out, but it will make quite a difference if we fix the board flush to the underside of the plastic. Then again, it's not a massive problem to sort that out.
There's a good chance we'll be making PCBs for a while yet, until we settle on a final design!