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