CHAPTER 13 ■ SOLDERLESS BREADBOARD SETUPBecause only a short amount of the plastic insulation is already stripped off of the end of the snap
connector’s wires, strip off a little bit more. Then insert the bare ends into the binding post holes
(see Figure 13-3).
Figure 13-3. Inserting the 9 V snap connector’s wire (stripped) into a breadboard post
Make a short length of red and black #22 American wire gauge (AWG) copper wire and insert them into
their respective post holes. You should wrap the wire ends around the metal portion of the post to achieve a
reliable connection. Place the short lengths of #22 wire into the desired holes of the breadboard. (Skip ahead
to Figure 13-8 for a photograph of the battery and post connections as viewed from a different angle.)
Electricity will flow from the battery terminal, through the snap connector wire, to the post, to the
#22 wire, and finally to the breadboard hole.
An advantage of attaching the power source to the binding posts is that you can conveniently connect a
multimeter to the banana jacks atop the posts to check voltage. Also, you can disconnect the 9 V battery from
the snaps and connect a wall adaptor to the binding posts.
■ Caution Never connect a battery and a wall power source to the same circuit at the same time. If you still
want to leave the batteries connected to the circuit, rechargeable and non-rechargeable batteries will require
specifically designed protection to avoid destruction when the wall power is applied.
Choosing a Power Switch
How suave is it to lunge after your out-of-control robot and rip out the batteries? Polished robot designs have
power switches. Easily accessible power switches are vital during prototyping, as the circuits may suffer a few
shorts and power overloads during development.
Unfortunately, few switch sizes are compatible with breadboards. Either the switch leads are too
thick or they are spaced apart at a distance other than 0.1 inch. As such, you can’t push the switch into the
breadboard holes. Bending or trimming the power-switch leads is rarely successful, as the switch needs to be
firmly in place or else it falls out when you physically try to use it.