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Electronics, mechanics, robotics: Huh?

Do you dream of building elaborate Erector Set-types of mechanical structures — perhaps a model of the Golden Gate Bridge with pulleys and levers moving objects around? Is your goal to create a robot butler with a programmed brain that enables it to serve your every whim? Well, those aren’t exactly what we categorize as electronics projects. Certainly, electronics projects are often combined with mechanical structures that use motors, and a robot has electronic components driven by microcontrollers and computer programs. In this book, though, we focus on projects that use simple electronics components to form a circuit that directs voltage to produce effects such as motion, sound, or light. By keeping to this simple approach, you can pick up all the basic skills and discover all the common components and tools that you need to work on a wide variety of projects for years to come. For these projects, you don’t have to become a mechanical or programming whiz. An electronic circuit might run a motor, light an LED display, or set off sounds through a speaker. It uses various components to regulate the voltage, such as capacitors and resistors. A circuit can also use integrated circuits (ICs), which are teeny, tiny circuits that provide a portion of your circuit in a very compact way. This saves you time micromanaging pieces of the project because somebody else has already done that job for you, such as building a timer chip that sets off a light intermittently.

Programmable versus nonprogrammable

ICs are preprogrammed or programmable. And that brings us to our next distinction. Although we do use ICs in many of our projects — for example, in the form of a sound chip that’s preprogrammed with beeps and music — for the most part, we keep away from programmable electronics. In order to work with programmable electronics, you have to get your hands dirty with programming code and microcontrollers, and that’s not what we’re about here. Instead, we focus on building electronics gadgets that teach you about how electricity works and get your mind stirring with ideas about what you can do by using electronics, rather than computers. Don’t get us wrong: Microcontroller projects can be a lot of fun.

Mixing and Matching Effects

The possibilities of what electronics projects can do are probably endless; on a basic level, the projects in this book use electricity to do a variety of things, from running a small cart around the room to setting off a sequence of lights or sounds. Generally, most electronics projects consist of four types of elements:

  • Input: This sets off the effect, such as a remote control device or a switch that you push. An event and a sensor, such as a motion or light detector, can also be used to activate an effect.

  • Power source: We typically use batteries in these projects.

  • Circuit: Components that control the voltage — such as transistors, capacitors, amplifiers, and resistors — are connected to each other and to the power source by wires and make up the circuit.

  • Output: This is what is powered by the circuit to produce an effect, such as speaker emitting sound, LED lights going off, or a motor that sets attached wheels spinning.

Battery-powered versus 120 volts+

One other thing that we made a conscious decision about when writing this book was that we didn’t want you tinkering with high-voltage projects. Electricity can be dangerous! Keeping to about 6 volts keeps you reasonably safe whereas working with something that uses 120 volts — like the juice that comes out of your wall socket — can kill you. While you’re discovering the basics of electronics, our advice is that it’s better to be safe than sorry. When you get more comfortable and more knowledgeable about tools and skills and safety measures (which we put a lot of emphasis on, especially in "Avoiding shocks" section), you might explore higher-voltage projects such as high-powered audio or ham radio projects. In this book, we show you how to work with low-voltage batteries and still have fun in the process.

What Can You Do with Electronics Projects?

You get to explore a number of variations in the projects in this book. And sure, this stuff sounds like it might be cool, but what’s in it for you? Electronics projects offer three benefits (at least):


The thrill of making something work all by yourself

A boatload of useful knowledge

Figure 1