Tree Climbing Robot

Step 5 Power, cont.

The Arduino and the logic circuitry for the motor controller are both powered by a 9V battery.  While the Arduino can take 9V input, the logic circuitry requires 5V, so I wired a 5V regulator in paralleled to the 9V going to the Arduino.  Now, why did I not just take advantage of the Arduino's internal 5V regulator?  Well, basically I ran out of pins, and I did not want to overdraw the Arduino.  In addition to the regulator, I soldered a barrel power connector to the 9V end of the circuit, to fit into the Arduino.  Finally, I added a DPDT toggle switch to break the 12V battery circuit as well as the 9V battery circuit.