CHAPTER 13 ■ SOLDERLESS BREADBOARD SETUP
I’m aware of a couple of switches with solderless breadboard dimensions (see Figure 13-4). They’re so
indispensable that you should have a dozen on hand. The EG1218 switch is more compact, which can be
advantageous as your robot’s circuit board runs out of space. The 600SP1S2 switch is a little easier to toggle
because of its larger size. Table 13-2 lists suppliers of breadboard-compatible switches.
Figure 13-4. Breadboard-compatible switches: EG1218 (left) and 600SP1S2 (right)
Table 13-2. Breadboard-Compatible SPDT Slide Switches
Supplier Part Number Price Description
Mouser 612-EG1218 $0.58 E-Switch EG1218 SPDT Slide Switch
Digi-Key EG1903 $0.58 E-Switch EG1218 SPDT Slide Switch
Solarbotics SWT1 $1.35 E-Switch EG1218 SPDT Slide Switch
Solarbotics SWT1A $3.00 E-Switch 600SP1S2 SPDT Slide Switch
SparkFun COM-00102 $1.50 E-Switch EG1218 SPDT Slide Switch
Electronix Express 17SLDH251 $1.30 E-Switch 600SP1S2 SPDT Slide Switch
Understanding SPDT
Slide switches are activated by sliding the actuator back and forth. The term SPDT stands for single pole,
double throw.
Think of SPDT like a tall metal pole standing in the middle, separated from wires on the left and on the
right. When the actuator is slid to the left, the metal pole is thrown onto the left wire, connecting the pole
and left wire. When the actuator is slid to the right, the metal pole is thrown onto the right wire, connecting
the pole and right wire.
Other than for a brief second, the metal pole is not standing completely disconnected in the middle.
It either slams down on the left side or slams down on the right side. At no time do the left and right wires
touch each other. Nor can the pole touch both the left and right wires at the same time.