A few people noticed something odd to the left of my Q119 sequencer from synthesizers.com. This is my trigger expander, basically I wanted something that would let me trigger noise shots, or toggle end points on the sequencer.
Now, synthesizers.com very kindly put a header on the back of the Q119 which brings out the key signals you need to do this, so adding an external trigger module was simply a case of reverse engineering the pin out and making a PCB.
This shows the PCB, and what I wanted to accomplish was that this was something people could make themselves rather than something I was going to sell. Why? well a number of reasons, I don’t honestly believe many people would be interested in buying and also the cost of the switches would make it quite an expensive module to sell, for what it does.
So I made it through hole, this was a huge pain in the butt, routing PCBs with surface mount parts is so much easier because you can run tracks under pads, with through hole, every track has to go between the holes. Add to this the fact I wanted to keep it 1U wide.
This PCB ended up being 4 layers, but is still quite cheap (4 layer PCBs from china only cost a couple of dollars more than 2 layer versions).
You’ll need to be careful about the order in which you solder parts on, I’d suggest that the second to last is the switches and the final parts are the LEDs (so you can position them at the correct height.
You’ll also need to solder ground and output wires to the three connectors which are not mounted on the PCB.
In the ZIP file of the project I’ve included the schematics, gerbers and KiCAD files you need so you can make your own, or tweak the design as you see fit.
If I was to make these again, I would pretty much certainly make it surface mount to make it easier to route and this would make it cheaper to manufacture in quantity.