I built a trigger wire by taking a short mono 3.5mm ts wire I had lying around, snipping it in half, and splicing in speaker wire. I stripped the ts cable jacket and +/- wires, twisted them with stripped speaker wire (keeping negative and positive wires separate of course), and used heat shrink to secure and insulate the twists. I didn't even bother with solder -- just a pocket knife, heat shrink tubing, and a cigarette lighter. I was completely lazy about it, but I now have a 25' trigger wire that works perfectly.