FREDDY "THE EXTERMINATOR"

Figure 1: Side-Shot of Freddy

Project: Freddy "The Exterminator"
Author/Designer: Greg Fredericksen

My name is Greg Fredericksen and I live in Gig Harbor Washington.

I am an electronics technician.  My interest in robotics started a few years ago when my stepson wanted to go to the Seattle Robotics Society meetings.

After going to those meetings both he and I were hooked.  Being new to this technology, I had many questions like: what microprocessor to use, what software language would be best, and what in the world would I build?

It took a while to figure those things out, but finally I chose a 68hc11 for a microprocessor (used by many at SRS), Interactive C for the software (for ease of use since I am new to programming) and the idea of Freddy (a robot with a purpose).

Freddy is a robot designed to spray Raid (or some other bug killing spray) on hornet nests. The robot travels on boards (white with a black line). The boards are long enough and can be lined up so you can be far away from the nest so you don’t get stung. The robot will follow the line by using a hc11 with a line-following program written in IC. By use of a camera and RF transmission I can see the location of the robot and stop it close to the nest.

Figure 2: Line following board.

I used the TWS-434 and RWS-434 from Reynolds Electronics as my RF remote control to rotate, tilt, and fire the bug spray so it will exterminate the nest and return back to me.  Freddy’s future plans are to patrol the attic in my house and patrol the crawl space under my house for unwanted guests like bugs, termites and ants.  To accomplish this task I will lay out a coarse of boards (white with black line) in both those locations.  The cost of this project (so far) has reached about $400 and has taken me about 200 hours to do.  The unique characteristic of Freddy is that it is practical.  I will use it often to inspect my house in areas I would not like to inspect in person.     

The idea of “FREDDY THE EXTERMINATOR” came about when I was putting a wheelbarrow under my deck last summer and got stung by a swarm of yellow jackets.  They had built a nest under the deck where I could not see it.  Later that evening after nursing my wound and buying some wasp spray I went outside with a flashlight to search for the nest.  I thought it sure would be nice to have a robot to find the nest and destroy it with me at a safe distance.  I did destroy the nest that evening but I have a better way of dealing with them next time – and you know they always come back!

Figure 3: Processor Board

The microprocessor board I used is from Axiom manufacturing. I rewired and reconfigured it into a handy board / rug warrior board configuration. I used Interactive C from Newton Labs to program it.  The microprocessor is a 68hc11a1fn.  The five A/D ports on the hc11 are connected to photo-resistors, which will detect and follow a black line laid out on a series of boards. The robot base is made of two Fuji 1 inch video tape reels.  The motors and gears used for the spray mechanism are from toy robotics kits I bought at Goodwill.

Figure 4: Freddy Following The Line (Armed & Ready)

The most difficult part of building Freddy was the time element.  After working 8 hours a day, driving home for 60 minutes (if lucky), eating dinner, and watching the news, I would have about 1 or 2 hours to work on Freddy before it was time to retire for the evening.  I found it was hard to keep motivated and keep the project moving, sometimes it would be a week before I got back to working on it.  Often I would have to make design changes that nullified two weeks or more of work.  Weekends were primarily for yard work and household projects, I worked on Freddy a lot when it rained.  Finally I would say the two things that helped me out the most in finishing this project were the drive and determination of my stepson with his projects and the patient understanding of my wonderful wife.

Contact Greg: Greg Fredericksen
Check out some more awesome robot projects at the First Internet Robot Contest web site: http://dec1.wi-inf.uni-essen.de/~astephan/robots.htm

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