Keith Best built this Scooter from Graymark

scooterThe manual that Graymark included with the Scooter kit has four major sections: Electrical theory, electrical construction, mechanical construction, and a testing & debugging section. If electrical construction is completed cleanly and correctly, then the debugging section is unnecessary. It’s a comprehensive, easy to read, step-by-step manual.

Once I was able to distinguish between all the different resisters, electrical construction was a snap. The directions are very clear and easy to follow. A little as left to be desired in the descriptions on the resisters. For example, the resisters used are of the four-color variety. (Three colors designate the value and the fourth color designates the variance in percentages.) All the other electrical parts were easily identifiable via their part numbers printed on the transistors and capacitors.

It does take a little to get used to soldering on a printed circuit board. By the fifth joint, however, soldering was easy.

Once the electrical construction was complete, I began the mechanical construction. The one difficulty I noticed was that, given the small size of the miniature nuts, bolts, and washers, the magnetic force of the motor is stronger than gravity. This made attaching the motor to the chassis especially challenging, but not impossible. Fortunately, the kit does come with about 12 spare nuts, a spare screw, and 5 spare washers.

Construction was completed in just under 7 hrs. Of course, that includes occasional breaks to refill my teacup.

Recommended tools for building the kit (in addition to the tools mentioned in the manual): A shallow bowl and a wet sponge to keep the soldering iron clean, and a relatively strong magnet to pick up all those tiny nuts, bolts & washers. (These have a way of jumping off the table.) Don’t forget some micro-tweezers that clamp on like vice grips.

Unfortunately, however, the Scooter seemed to require brand new batteries (2xAA) to function at all. But then it tends to go zipping off at around 15 -> 20 mph! I think I need to add a rheostat or resister somewhere to slow the motor down. (But that would then affect the timing circuit, composed of two capacitors, 1 mf and 40 mf. At any rate, unless I operate it with my arms around it (forming an arena), it goes zipping off the table to certain destruction!