Fun with a ISU Inclinometer

For a while now, you've been able to buy digital levels. Amazingly, they will display angles within 0.1 degree.

As some of you know, I've been on a quest for a good way of mapping hills, and I found that you can order up a inclinometer from the same company that makes the digital levels. Which I did.

It's a pretty cool device - you give it 5 volts, and then it gives you the current angle back through a serial port. In the simple mode, it will send you this data every 5/8 of a second.

So, this weekend I hooked it up to a level converter (the inclinometer speaks TTL rs-232, so you need something like a maxim 232 to convert that to real RS-232), connected it to my laptop, and exercised the new Whidbey SerialPort object. I wrote a little logger, and headed out to gather some data on the hills around my house. Thirty minutes later, I had my data, and I imported it into excel.

And it looked weird. Some of the data looked really nice, and some of it had big spikes in it - both in the positive and negative directions.. Took me about twenty minutes to figure out the problem.

Care to guess what I forgot, and how I'm going to fix it?