FPGA Robotics Projects - Rapid Prototyping of Digital Systems - page 265

7. A charger for the 7.2V or 8.4V battery pack . An adjustable DC power supply can be
used to charge the battery if it is properly adjusted and timed so that the battery is not
overcharged. Overcharged batteries will get hot and will have a shorter life. Automatic
peak-detection quick chargers are the easiest and most foolproof to use. These chargers
shut off automatically when the battery is charged. One quick charger can be used for
several robots as a full charge is achieved in less than 30 minutes with around 5 Amps
maximum charge current. Inexpensive trickle battery chargers deliver only around 75
mA of charge current, and they will require several hours charge the battery.

• Parts Available from an Electronics Parts Store

8. Three 40-pin .1-inch double row PC board mount female header sockets , DigiKey
#S4310 or equivalent . These sockets are soldered into a small 0.1” center wire wrap
protoboard that fits into the Santa Cruz Expansion connector on the UP3. This is used to
connect servos and sensors to the UP3 board.

9. A 2 to 3 inch strip of .1” single row breakaway headers. DigiKey #S1021-36 or
equivalent These headers are used to make custom servo and sensor connectors on the
protoboard. They can be soldered to the protoboard.

10. A small wire wrap protoboard with holes on .1” centers cut down to 2” by 2.8”. A
This is used to make a protoboard for use with the UP3 board. The protoboard contains
connectors for servos and sensor. A protoboard with solder pads makes it easier to
mount the connectors.

11. A miniature toggle switch with solder lug connections. The switch should have a
contact rating of more than two amps (Radio Shack #275-635B or equivalent). Only two
contacts or single pole single throw (SPST) is needed on the switch to turn power on
and off. If all of your servos and sensors connect to the UP3 and do not use the
Vunregulated supply, you could eliminate the switch by using the UP3's power switch.

12. Approximately 9 inches of small-gauge twin-lead speaker wire. This part is used to
connect power to the UP3 board. The wire must fit into the DC power plug (part# 11).
Typically, 20-22 gauge wire is required. Two individual wires can also be used, but twin
lead is preferred.

13. A 1-inch piece of small heat shrink tubing or electrical tape. This part is used to
insulate a splice in the twin-lead power wire.

14. A Coaxial DC Power Plug with 5mm O.D. and 2.1mm I.D., Radio Shack Number
274-1567 or equivalent. This power plug fits the power socket on the UP3 board. A
different size plug is needed for the UP2 board, use #274-1568 that has a 2.5mm I.D.

15. An assortment of small wire jumpers and connectors to attach wires to the male
headers on the UP3 . These are the jumper wires commonly used for protoboards. Two