Comobot by Alexander Wiedekind-Klein

In my spare time I've constrocted a small mobile robot named COMOBOT. His name stands for COmpact MObile roBOT. I have robot constructed him to get experiences with designing and programming autonomus and tele- operated robots. He could be used as an universal platform for AI-experiments. All electronic circuits, software and mechanical parts are designed by myself to keep the costs low. COMOBOT has got three wheels. The two bigger wheels are driven by two independent gearmotors with incremental sensors. This gives COMOBOT the ability to turn around himself and this makes navigation much more easier. The most important sensors of the robot are two ultrasonic distance sensors. The two sensors are mounted on two RC-servos. On this way the robot is able to scan his area. This information is used for navigation and collosion avoiding. The robot could be controlled by a PC via a serial RS485 interface. This allows the usage of an powerful computer and a comfortable development of the steering software. Equipped with a wireless serial link he could be fully autonomus. It is also possible to control the robot by another on-board computer like an 386EX.
Technical Data :
a) Size/weight:
He is about 25cm (10 inches) wide, long and tall. He weights about 
2kg. His body is made of an aluminium frame.
b) Computer:
The robot is controlled by an 80C535 (12MHz) microcontroller board 
with an 32kB EPROM and 32kB RAM. The board is developped by myself 
and has got some more features like real time clock, RS485 interface, 
six more 16Bit Timers and another 24I/O lines. Important data can be 
stored in a 128Byte serial EEPROM. The controller has eight analog 
cannels wich are connected to most of the sensors.
c) Sensors:
- Two independent ultrasonic distance sensors. The sensors are mounted
 on two RC-servos. The firmware provides a 360o scan of his world.
- The two driving DC motors have incremental sensors. the robot can 
 control his speed and measure the travel distance in 1.28mm (1/20 
 inch) increments.
- Aditional to the ultrasonic sensors he has got a lot of feelers and 
 bumper switches to detect any collision.
- The connection of light- and temeratue sensors are planned for the 
 near future.
d) Actuators:
The robot has got two PWM controlled gearmotors and two RC-servos for 
turning the ultrasonic-distance sensors. For future use up to six 
RC-servos can be controlled.
e) Firmware:
The robots firmware is written in C and provides a lot of different 
commands to read the sensors and to move all actuators. All basic 
routines like distance measurement, area scan and actuator control 
are done by the firmware. Also the software supervises the feelers 
and bumper-switches. The serial protocoll is designed for universal 
RS485-bus applications. So up to 32 COMOBOTs or devices can be 
controlled by one PC.
f) Power:
The whole robot is powered by an 6V 1,3Ah recharbale lead-acid battery.
This keeps him alive for about 2 or 3 hours (depends on the movements).

Project Status (May '96) :
At the moment I'm working on controlling PC-software. The software is 
written in C with the WATCOM C/C++ Compiler.

Future plans :
First I want t spend COMOBOT some more sensors (light and temperature) 
an a wireless serial link. If the software works fine and is not too 
complex I will replace the external PC by another on board computer 
like an 8051 or if necessary a more powerfoll one (386EX, 80C166).
After that I'll build annother bigger Robot whith an build in PC 
(I'm already collecting parts for this robot).

At the moment this work is a very nice hobby, but maybe some day 
I've got the posibiliy to make my profession ot of it....

For more and frequently updated information see COMOBOT's homepage at:

If you have any requests, comments or suggestions, please send an 
E-mail at:

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