Gadget by John Whitten

Gadget is based on an R/C truck chassis and uses several 68HC11's for
the low level control functions and a 486DX/66 8Mb RAM 1Gb Hdisk
Linux system for higher level functions. The project is still 
currently underway. Much more info can be found at my web page
http://www.vnet.net/wizorg/wizorg.html. 

The robot features
  Ultrasonic Ranging (Sonar)
  Ultrasonic Proximity Detection (*)
  IR Ranging (*)
  IR Proximity Detection
  Sensor Head Turret (Tilt/Rotate)
  Several CDS photodetectors
  Several Thermisters for Temperature sensing
  3 Mercury Tilt Sensors
  Front and Rear "Whisker" sensors (*)
  Physical Contact "Bumper" sensors (*)
  Dynamic Power Distribution System (*)
  Recharging Arm (*)
  Video Camera
  Video Frame Grabber (*)
  IR Communications
  Wheel Shaft Encoders
  Drive Motor Current Feedback
  Various Operator I/O Lights & Switches

(*) Means this item is still in development and not currently ready
    for attachment to the Robot yet. Most of these I've already
    hammered out and am awaiting final production of the Robot's
    main electronics board to implement.

Difficulties:
  First of all I wouldn't recommend using a 4-wheel base for use as a
  robot. There are numerous navigational problems that you encounter
  when doing that. Tank-type treads, three-wheeled, or walking robots
  are much better (IMHO).

  Secondly, building Ultrasonic Ranging is VERY easy (though it took
  me a month or two to work it all out) and you can do it accurately
  and reliably for less than $25 in parts (I'm assuming you have NO
  parts in your junkbox and buy virtually everything from some
  obnoxious retailer).

  Thirdly power is a major problem. With small robots or robots that
  don't have as much in the way of electronics, this may not be so
  bad. I have a 486 PC with a 2-1/2" hard disk and so the power gets
  sucked down pretty quickly. I'd like to replace the motherboard
  with one out of a laptop. I think that would relieve the problem
  quite a bit... anybody have a nice 486 laptop they'd like to donate
  to the project ??? :-)

Overall I'm very pleased with the development of the robot so far. As
I mentioned earlier, the project is still in the works though and I'm
having a ball working out all the details. Not to mention all the new
friends I've met while perusing the newsgroups and web sites looking
for ideas and stuff. Be sure to check out my home page at 
http://www.vnet.net/wizorg/wizorg.html for more information. This page
is also under construction. There are a lot of interesting robotics
and electronics related links there too.