Digital Signal Processing Reference
In-Depth Information
The battery is moved towards the rear for balance to place the weight on the
rear skid. The Velcro on the base should be around 2 inches longer than the
battery pack towards the rear of the robot to allow for positioning of the battery
later on to balance the robot. The wire and connector on the battery pack should
also be attached to the base to prevent it from dragging on the floor. Attach a
small piece of Velcro on the rear of the connector so that the battery wires can
be attached to the base. Attach the battery pack to the base.
On UP3, UP2, and UP1 boards, solder a 60-pin female header socket (part #7)
to the expansion header B location. Attach the FPGA board to the top of the
base with 4-40 screws (part #18), using the hex spacers provided on the FPGA
board (part #14). Figure 13.19 is a close-up photo of the top of the FPGA-bot.
Double check power connections and polarity with an ohmmeter. The inner
contact on the power connector should be +7.2V, the outer contact is ground,
and the toggle switch should turn it off. Then plug the power connector into the
FPGA board. Plug in the battery connector and flip the power switch. An LED
should light up on the FPGA board indicating power on. The Cyclone
expansion B header socket faces the front of the robot. DE2 and DE1 boards
already have expansion sockets soldered to the board.
Mount the wheels (part #5) on two modified servos (part #3). If you are not
using the special servo wheels, you may need to enlarge the hole in the center
of each wheel by drilling it out partially with a drill bit that is the same size as
the servo output shaft. The depth of the hole should be slightly shorter than the
servo output shaft and not all the way through the wheel, so that the wheel does
not contact the servo body. The servo output shaft screw is inserted on the side
of the wheel with the smaller hole. A washer may be required on the servo
screw. The wheel should not contact the servo case and must be mounted so
that it is straight on the servo. CA glue or Blue Loctite can also be used to
attach the wheels and screws more securely to the servo output shaft.
Attach the servos to the bottom of the base using double sided foam tape (part
#17) or a more durable servo mounting bracket. The servo body faces toward
the center of the base. Be sure to carefully center the wheels in the plastic-base
wheel slot. If you are using foam tape, make sure all surfaces are clean and free
of grease, so that the foam tape adhesive will work properly. Lightly sanding
the servo case and adding a drop of CA glue helps with tape adhesion. Route
the servo connector and wire through the holes provided in the base.
Attach a tail wheel to the base or a skid (part #19) at the rear of the battery
pack using layers of foam tape as needed. Move the battery as needed so that
the robot has proper balance and rests on the two wheels and the rear skid.
Attach another skid to the front of the battery pack using several layers of foam
tape. The front skid should not contact the floor and at least ΒΌ inch of clearance
is recommended. The front skid only serves to prevent the robot from tipping
forward during abrupt stops.
On the UP3, attach a 3-pin .1 inch header (part #9) to the small wire wrap
protoboard in an open area. One is required for each servo on the robot. Solder
wires from the appropriate pins J2 and J3 connections on the protoboard to the
new header pins. The three wires on the servo are Vcc (4.8 to 6 volts), ground,
