This is a Frequency Counter circuit, designed and built by me and my lab partner for one of our courses. It does work, although it was not connected when I took the picture, and it no longer exists.

Unfortunately, I can't find the logic diagram I drew for this thing, and I know I already got rid of the physical layout drawing, but it was ugly anyway, especially since we used it as a checklist during construction.

This whole process comes with a lot of good advice for aspiring electricians: Make a comprehensive logic drawing first, then make a drawing of the physical layout of the circuit, and then check off each component/wire on the physical layout drawing as you place them. You don't have to be an artist to make good logic schematic and layout drawings, though it probably helps.

Of all the other circuits we saw others building, this was one of the best; you may notice that very few of the wires overlap eachother, and there are few long wires. It's hard to see from this view, but the wires were also very close to the board, so that we could reach and move around components if needed. The location of the readout LEDs is a little weird, but we ran with it... It was much easier to do that from a design perspective.

Design time: 6 hours (including research and drawings)
Construction time: about 5 hours
Troubleshooting time: About 5 minutes (We mixed up two wires, but it was obvious from our readout)