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.