Monday, March 27, 2006


As I mentioned, I've been rather busy lately and haven't had time to post. Fortunately, at least one of the things that has kept me from posting about robotics is robotics. Let me give you a first glimpse of my BHAG, my Big Hairy Audacious Goal. My BHAG is:

A Robotic Blimp!

My goal is to build a blimp with control system that can navigate around a room without human intervention. One of the principle goals is that the system be CHEAP. I am using commercially available parts wherever possible to reduce the amount of development I have to do. Here's what I've got so far.

The blimp platform is a toy blimp by Huan Qi, sold here in the US by Raiden Tech ( It's got two propellers which are driven by very small electric motors. The motors are mounted on a shaft which is also motorized to allow both motors to be tilted +/- 90 degrees. Each motor can be driven forward or reverse, so there are 6 possible commands for the transmitter to send to the blimp. The transmitter is powered by four AA batteries, and the blimp is powered by a capacitor which is charged using a plug built into the transmitter. $25 plus shipping.

To allow the blimp to be controlled from a PC, I used a commercially available I/O card and a simple home built board to connect the I/O card to the blimp transmitter board. The I/O card is the Elexol IO24, which I bought from Hobby Engineering ( The things I liked about this card are: it has a USB interface, it supports 24 pins of input/output, it was pretty cheap. $70 plus shipping.

To connect the IO24 to the transmitter required a set of transistors. I mounted them on a circuit board with a current limiting resistor and a pull-down resistor. Don't look too close at this board; it shows off my very poor soldering skills. Hey, I'm an aeronautical engineer, not an electrical. The transistors and resistors came from an assortment, so I could tell you the exact price, but certainly less than $15.

So that's the first phase of my project. The hardware is for this phase is together and tested. The software is mostly written and as an engineer, I'm proud to say that it is written in Fortran. Now on to the challenge: how will the blimp know where it is in the room?


For those of you who have read this blog back to its beginning, you may recall that the blog and our family's foray into robotics all started when my daughter, Dragonfly, got involved with her high school robotics team, which builds a robot for the FIRST robotics competition. Last year Dragonfly was deeply involved in the team, and Mermaldad got only slightly involved, helping the team solve some problems near the end of the build season and cheering for them at the regional competition.

This year we were involved once more, with Dragonfly just as busy and Mermaldad getting a little more involved, although work commitments kept him from being there as much as he'd have liked. Even Wolfbait got involved a little. Since he was still in middle school and thus not officially part of the High School Team, he was named a volunteer and enthusiastically admitted to the build sessions.

One of the things that I really like about FIRST is that it's not only about the robot. Sure, the robot is the most tangible product of the students' effort, but FIRST offers many awards for teams in a variety of areas. The highest award, considered even more prestigious than winning the competition itself is the Chairman's Award. The Chairman's Award goes to the team that "best exemplifies and demonstrates the values that FIRST emphasizes".

The FIRST world revolves around the concept of "gracious professionalism". We compete against the other teams, but they are not our rivals, they are our colleagues, and we treat them with respect and courtesy. Teams are encouraged to help each other out. In fact the structure of the competition, where each round is played 3 on 3, means that the team you played against last round may be the team that you play with the next.

Last year, when we went to our first FIRST Regional Competition, we had a pretty good idea what to expect from the game. What we didn't expect is the enthusiasm of the students. Teams had cheering squads, were dressed in wacky outfits, and brought along mascots. The announcers include a DJ who plays music all day long. It's a lot of fun to watch!

This year our team's robot didn't fare all that well in the standings. At the end of the competition we were ranked in the mid-30s out of 42 teams. This is slightly better than last year's performance, but I believe the robot was a much better machine. Our last 3 matches were plagued by a problem with the controller, something out of the team's control. It was disappointing, but all part of the competition. The really nice thing was that near the end of the competition, one of the sophomore students came to me and the team advisor and said (and I paraphrase), "We ought to divide the team up in two and have our own mini competition using all the parts from the last three years. I think we'll learn a lot from building more. I learned so much more this year, when I had to build stuff myself than last year when the seniors did everything." To me, that's what it's all about.

Not Dead Yet

It has been so long since the last post to this blog that even loyal readers may have concluded that it was dead. It has been sleeping quite soundly, but is not dead yet. A combination of Christmas activities, a major project at work for Mermaldad, the FIRST robotics build season and regional competition, and actual robotics work at home all contributed to our delinquency. Having reached a brief lull in these other activities, I'll try and catch up with a few posts.