The Right Tools for Working on Your BeagleBone Projects
The most important tools you need to start creating prototypes of your BeagleBone projects are described here. After you have a diagram and the necessary components, you need to know how to connect the whole thing — easy to do with a breadboard, jumper wires, and a pair of needle-nose pliers.
Simply put, the breadboard is what allows you to create prototypes so that you can test and experiment with them without making permanent connections that you can’t undo. With a breadboard, you can reuse the components of your circuit without any kind of setback.
What makes the breadboard so special? Beneath all the holes in it are copper tracks, which enable you to create metallic connections for current to pass through without committing to more permanent solutions (such as soldering).
There are many sizes and types of breadboards, but the concept is always the same: If you plug a wire into one of the holes in a breadboard, you connect the wire to a copper track that keeps all the holes in its row connected.
The copper tracks are normally covered by a plastic coating. If you’re looking at a breadboard and can’t see the copper, it would look the same as the figure under the plastic. Don’t try removing the plastic coating to check it out for yourself!
To better understand the connections within the board, refer to the first image. On the long sides of the board are two lines of holes separated from the central holes. On most boards, these holes are delimited by a red (+) and a blue (–) line, which suggests that you use them as a positive power source (+) and a negative power source (–), respectively.
The copper tracks beneath those holes are horizontal and are broken at the center. If you connect the positive side of a 9V battery to one of those tracks, any electrical component leading to the same track will be fed with 9V.
Some breadboards don’t have the red and blue lines, whereas others don’t exhibit the break at the center of the horizontal lines, but their layout is still exactly the same as shown.
At the center of the breadboard are shorter lines in parallel with the short side of the board. The tracks there are vertical and are also broken at the center. For components with multiple legs, such as integrated circuits (IC) and pushbuttons, this trench in the center prevents the legs on one side from connecting to the other. (Some tiny breadboards have only the vertical copper tracks.)
In a sense, the horizontal and vertical lines are the same things — copper tracks — so you can connect things however you want, such as connecting the battery to a vertical line. Conventions exist for a reason, however; they’re often guidelines to the easiest way to accomplish a task and also ways to keep you organized.
Follow this convention: Horizontal is for power and ground; vertical is for everything else. The following figure shows a pushbutton circuit with a light-emitting diode (LED) and a 9V battery.
Components in the world of electronics are very, very tiny. Using needle-nose pliers to plug your resistors, LEDs and ICs into your breadboard can save you lots of time and protect your sanity, since using human hands alone often becomes a headache — especially as the breadboard becomes clustered.
Jumper wires (which are also known as jump wires or simply jumpers) are usually used with a breadboard because they’re easy to plug into holes. These wires consist of copper, an insulator so that the electric signal is protected, and a connector.
Depending on the type of connector on the ends of the wires, jumper wires can be female/female, female/male, or male/male. Male connectors are exposed, unshielded electrical terminals that can be easily inserted into a receptacle, such as the BeagleBone, the breadboard, or a female connector to ensure a robust electrical connection.
Jumper wires are definitely the easiest way to establish communication among your LEDs, sensors, resistors, and other electrical components and the BeagleBone. There’s no need to cut, trim, or bend them; they’re ready to use from the moment you get them!
There are several more tools used in circuit design, but there isn’t space in this book to cover them all. The tools presented in this chapter are all that you need to start having some fun with the BeagleBone.