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Remote-controlled vehicles are very cool things. You can cause them to zip around your living room, tease your cat, and race with your friends. Building your own go-kart from scratch and using the power of infrared to control its every move are what this project is all about. How far you go in making a cool-looking car is up to you; here we’ve designed what we call an infrared go-kart — sort of like a VW Bug but just a little bit smaller.

In this chapter, you get to explore creating a go-kart that can go forward and backward and even turn left and right on a dime. Along the way, you pick up all kinds of tips about infrared transmitters and receivers as well as controlling motors.

The Big Picture: Project Overview

After you complete this project, you’ll have a little three-wheeled go-kart that you can control with an infrared transmitter, as shown in Figure 11-1. Here’s the rundown on the key features of this vehicle:

We use three wheels. Why three wheels? No kart you ever saw had three wheels, right? Well, the world of electronic projects isn’t Detroit, so we use three wheels because it’s simpler and it works. As soon as you use four wheels, you have to add a suspension system to ensure that all the wheels stay in contact with the ground, especially when that ground gets uneven. For a simple electronics project, where the focus is on the electronics and not the mechanics, you don’t want to deal with a suspension system.

The infrared remote control works along the same lines as your television

remote control. You supply an electric current that causes the LED to generate infrared light. The IC in the transmitter modulates the electric current running through the LED according to which button you push on the transmitter: on/off, motor right (we’ll call this motor R), or motor left (motor L). If you aim the transmitter at the infrared detector on the kart, the detector turns the infrared light back into electric current.

That current is then interpreted by the receiver circuit on the kart to turn the motors on or off, reverse motor R, or reverse motor L (based on which button you push).

So what, exactly, will you be doing in this project? The project involves 1. Putting together the electronic circuit for the IR transmitter and fitting it into a plastic box with buttons that you use to control the movement of the go-kart

2. Putting together the electronic circuit for the IR receiver/motor driver

3. Building the base for the go-kart itself and attaching the various bits to it