The Horn Hack

The team had assumed they would use their usual solution of an air horn and that they would just buy one when they got to the country. It turns out that air horns aren’t allowed in Abu Dhabi or the Emerites in general—I guess because of huffing. So we didn’t have a horn, and you can’t just go out and buy a car horn for the solar car. Horns are actually nasty devices and you can’t just hook them up to the 12 volt system on the car.

We had a horn but needed to find a way to power it. We needed to figure something out or get a bigger battery. It seems like you can only buy car batteries in this country. So we had to figure something else out.

Joe looked into my eyes and gave me an inspiration. I thought of something loud that can be annoying on demand. So we went and bought some smoke detectors and a door alarm. But those didn’t pan out because they were too smart. We couldn’t figure out a good way to hack the circuitry to be annoying on demand—in the way that we needed it to be.

So it got to the point where we needed to make this horn work and needed a battery. So we were walking around a hardware store and saw a cordless drill with a 12-volt battery in it. I figured if it can drill a hole, it will have enough current to make the horn blow. We got it, wired it up and now the car has a cordless drill battery in it.

There is a probability of success at any point in time. I have my own internal threshold of where that is, and yesterday we were below that threshold. That’s why I went out and bought three plans worth of pieces. The first two plans didn’t pan out, but what we created was the best solution. It’s actually a real car horn.

These situations happen in every race. You’re going to have to MacGyver things up. I think everyone is capable of thinking like this. You just have to be in the right mind set and practice it. When it’s two days before the race and something isn’t working, you’ve GOT to make it work. A nonfunctional car is zero-percent efficient. In those situations you have to make a mind switch, make compromises and just figure something out.

Jeff Rogers, BSE’ 08, MSE’ 10 College of Engineering Computer Science