Saturday, February 17, 2007

My sabbatical has begun!

You may have noticed that I have not done many updates lately. That should change now that I am officially on sabbatical for the next 8 weeks! It sort of feels like summer vacation when I was a kid (except for the weather). It sounds like a lot of time but I will be busy getting rockhopper going. But don't worry, it won't be all hard work. Jane and I are taking a week long cruise leaving a week from today.

Ok, now more technical stuff...

I received a few more parts in the mail the other day. Most importantly my sonar units. I found some really nice units made by Devantech. I chose the SRF08 sonar because it should be easy to interface using an i2c bus and also because it has the ability to listen for multiple pings. I have not had the chance to do any work with sonar since college but what we found from experimenting back then was the first ping received is often not not always what you want. The plan is to take the data from 3 sonar units and feed that into a neural network. I will write up more on this later on. The plan for today is to just try to interface the sonar to my ARM board to make sure I can get readings.

I also ordered a digital compass, also from devantech. My first robot for the Trinity robot contest also used a compass. I found that while in a building such as the gymnasium at Trinity it will at first appear to give random readings. You can move in a straight line and have massive compass deflection. While this may appear random it _is_ consistent in a single location. I hope to be able to use this to help recognize locations inside the maze. The compass also interfaces using i2c.

1 comment:

Ross Knepper said...

Hey Doug,

Lisa Smith referred me to your blog. Good luck with the competition! I am a former HP employee. I returned to Lisa's and my alma mater, CMU, for grad school, where I'm in the Robotics Institute.

I am wondering about your choice to use sonar. Obviously, the price is right, but they introduce a lot of challenges due to reflections in your environment, which could be especially bad since all the walls are right angles. It makes me wonder how valuable the additional return signals will be, unless you have some fairly sophisticated filtering algorithms. I wonder if IR range sensors might be a little more effective, especially in such a small environment. They also have an advantage that a candle should give a recognizable signal in near-IR so that you know when you've found the target. I haven't priced IR range detectors, but they should be way cheaper than a $5000 LADAR!

It looks like an awesome project, so I'll be rooting for you. ;)

-ross