Step 8: Step 6: the Circuit
The sensible thing here would have been to use insulated electrical wire - the most common, if not ONLY, wire used for electronics, but that was not aesthetically suitable for what I wanted. So I took a piece which consisted of a fairly thick single strand instead of many thin strands, and stripped the insulation completely, leaving only bare wire. This looked much cooler, although it took a bit more planning to make sure no wires crossed. I wired the circuit according to the diagram below - two sets of LEDs in series, each set in parallel, as well as a 2.2 ohm resistor which is not in the diagram . I used tiny spots of PVA glue to hold the wire down the the sensor bar.