to see the video.
I started building mobile robots in 8th grade (1991). Since then I have worked on
several. On this page you will see some of the robots I have built as well as some basic
info about each. Click on the image if you want a larger view. Some of the robots have
video clips click on to see the video.
1991
Ok, This is the frame of my first robot. I used power window motors I found at a local junk yard for drive motors. The front and rear drive shaft run through the window motors and are bolted on to lawn mower tires with a few nuts.
1991
This is what my first robot looked like when it was done. It's task was to deliver mail in an office environment; but, it had some major drive/steering problems. The system ran on a Commodore 64 computer that I hacked to run from 12 VDU. The software was written in FORTH and would let the operator drive the robot around with a Joystick (from my Atari 2600) in learn mode. Then the operator would put the robot in play mode and it would follow through the routine it learned. The tank drive system made steering very unreliable and the system would get off track in under 1 min.
1992 Bot92
This is my second robot. It is actually built off the base of the first robot, but had a tricycle steering design.
1992
This robot was designed to roam around an office building at night and detect intruders. If it detected anything it would record it on video tape. This robot had much better steering, but still had drive problems because the 2 motors on the rear drive would get out of sync. This robot also ran on a Commodore 64 running FORTH.
1993
Well, I lost all of the pictures of my 1993 robot. It looked like the bottom of the 1994 robot (I added the top 1/2 in 1994). The robot had a much more accurate drive and steering system, but I had problems controlling the larger drive motors. The increases in accuracy was partly due to the use of an arc welder; I was able to weld my robot together instead of using pop rivets. I ran out of Commodore 64 boards and wanted some more CPU so I used a i286 running BASIC in this robot. I decided to build my own switching power supply to power the computer, hard drive, and control logic because I thought it would be much more efficient then buying an inverter to switch from DC to AC when the computer power supply would only go back to DC. As it turned out, the supply worked great until one day something happened with the switching logic I had built and I accidentally sent 24 volts throughout the system. After frying all of my hardware I decided to put this robot out of its misery and begin work on a few other projects.
1994 Bot94
This is a picture of me grinding a new weld on the frame.
1994
This was what the finished robot looked like, this robot actually turned out rather well. The steering and drive system were quite accurate because of the addition of encoders on the drive and steering shafts. However, the robot would still drift over time. To help correct this problem I added encoders on the drive and steering shafts to measure motion. I also built a sonar board that would allow the robot to measure the distance from objects on 3 sides. With the sonar system the robot could do a good job of correcting drifts by checking distance from walls and other objects. This robot used a i386 for CPU. and, I again decided to use FORTH once again.
1994
This is what it looks like with the sonar and top plate removed.
Instead of building another robot in the 12th grade I started NetRail, Inc. a transit free national backbone provider with POPs in 8 U.S. cities. I sold NetRail on 10/15/97 and have since been busy doing consulting work in the U.S. and abroad. I hope to put my hard-won wisdom to use again soon and build robot number five.
Nathan Stratton nathan@robotics.net
First Created March 6, 1998
Last Modified May 9, 1998