Nuts and Volts - May 2008

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BY JOHN MOUTON

Photo courtesy of Slot Car Corner LLC.

Microcontrollers are used in many different applications — motor control being one of them. So why not put a motor on something fun, like a slot car? This article will show how to turn an 18 volt, brushed DC-motored slot car into a micro-controlled super car using the PIC12F683 microcontroller. We will give the car adjustable speed control (a throttle!!), brakes (Midas doesn’t make them that small), and the ability to read the track and know where all of the turns and straight-aways are. You can even set your track up so that you can run a modified slot car against a non-modified slot car, and see who wins.

Everything you need to build this project — schematics, photos, references, sources, and a list of parts — is included. The possibilities for this project are endless — you can make it as easy or as complex as you want. My only warning to you is that once you start, it will be very hard to stop.

Getting started is easy. You can go to almost any hobby shop around or online to purchase a basic electric

slot car set with a starting price around $30. Purchase one that you feel is right for you, as long as the track and cars can take 18 volts DC and the slot cars have brushed DC motors. The track can be as long or as short as you want, and you can always add pieces to it later. For this article, I chose an oval layout for simplicity and explanation purposes. The exact slot car track set used in this article is the NASCAR Winners-cup set (Part LIF9544) purchased from www.mascr.com for $59.95.

Start Your Engines!

To begin with, take a look at Figure 1. If you look closely at the original slot car with its cover off, you will see that each terminal of the motor

■ FIGURE 1. Top and bottom views of the slot car — right out of the box.

NOTE:

The Microchip name and logo, MPLAB, and PIC are registered trademarks of Microchip Technology, Inc., in the USA and other countries. PICkit is a trademark of Microchip Technology, Inc., in the USA and other countries. All other trademarks mentioned herein are property of their respective companies.