In spite of my general opposition to the practice of body piercing, I managed to pierce my own today.

Dennis was having trouble with a cell-phone charger (it plugs into a car’s accessory outlet) and he brought it in for us to take a look at. We hooked it up to a PC’s power supply in my office. I have a junk PC in there that I use for testing boards. The first problem was figuring out how to connect the charger to the power supply. I happened to see a thumb tack on the desk right next to the PC, so I had the idea of pushing it through the insulation of one of the power cables and just clipping onto it with an alligator clip. That worked just fine (and is not that different from how normal insulation displacement connectors work).

That reminded me of a story my Dad told me once, how he and/or a friend of his ran a safety pin through a couple of wires on another guy’s pickup truck, connecting his brake lights to his horn. So every time the guy hit the brakes, the horn would sound. Ha ha! I love it!

Back to my own story. We still needed a second lead. We had connected 12V to the charger, but we also needed a ground. Scanning my office turned up a dental pick. These are exceedingly useful in the electronics trade, so I happened to have one on my desk. I picked it up and began pushing it through the other wire, and stopped as soon as it went through that, kept right on going and pierced the fingernail on my left hand.

Ouch!

It bled.

Dennis’ charger was supplying a hefty 5V on the regulator end. We didn’t have anything to probe the other end of the cable, but I’m guessing that’s where the problem is.

With a potential diagnosis made, I wanted to cover the tiny little hole in my fingernail so I wouldn’t get germs in there. But I also didn’t want to wear a bandaid on my fingernail. So I went downstairs to the manufacturing lab and got some super glue. One dot of that on the hole, and I was good to go.

Advertisements