Like every robot builder that wants to teach others how to build robots, I have built a sample robot, using parts from VCRs and bought only the minimum necessary to make the simplest robot I could think of. At the time I was using the Nemesis microcontroller, produced by Kronos Robotics, however this was not a good choice for Romania, because import taxes would have made their price almost double. Nemesis is a PIC 16F88 with a pre-programmed bootloader. This feature allows the user to program it from the serial port of the PC through a logic level adapter. Kronos Robotics also provides Athena, a free Basic compiler, lots of sample code and great support. Basic is easier to learn by young people, so I thought it is a good choice for beginners. And Nemesis costs only $12.95. A PIC 16F88 costs about $3, but needs a programmer (the cheapest I could find is $40) and the PBasic compiler costs $99. Too expensive. Now I would use an AVR ATtiny26 and Bascom-AVR for programming, cutting the price to about $15 for the whole project.
Here is a movie with the robot driving (fast) avoiding to crash into obstacles:
The only parts you will need to buy for this project are the Nemesis microcontroller, the SN754410 motor driver IC, a prototyping board, the LM2940 voltage regulator, a battery box, 18 pin and 16 pin DIP sockets, a 5 pin female socket, a strip of breakable male pins. I also bought a serial lever shifter to program the microcontroller from Kronos Robotics website.
All the other parts you can get from a VCR, but you will need 2 VCRs to get 2 identical motors. You will also need a few cable ties, a couple construction nails, wire, a couple small wood screws and 4 AA batteries.
|No||Item||Cost $ each||Quantity||Website and part number|
|1||Nemesis||12.95||1||Kronos Robotics #16406|
|2||Easy 232 serial adapter||9.95||1||Kronos Robotics #16167|
|3||40 pin straight header||0.99||1||Kronos Robotics #16290|
|6||HOLDER BATT 4-AA CELLS WIRE LDS||0.77||1||Digikey BH14AAW-ND|
|7||Conn header 0.1" single R/A 5PO F||0.44||1||Digikey S4105-ND|
|8||18 DIP socket||0.94||1||Digikey ED3318-ND|
|9||16 DIP socket||0.83||1||Digikey ED3316-ND|
|10||Grid-Style PC Board with 356 Holes||1.79||1||Radio Shack 276-149|
On the Electronics page we will go over the schematic to see how things work.