Step 3: Assemble the robot
Step 1: Screw the 8-32 one inch standoffs onto the 3 holes that you drilled and threaded. In the picture I temporarily put caps on the ends of the standoffs because they are too long, but I recommend that you cut them off with like a Dremel tool.
Step 2: Place the top Lexan base on the standoffs, and using the 8-32 screws you got, attach the top to the standoffs. Note: trying to thread metal screws into plastic can be hard, to make it easier, rub a little paraffin (candle) wax on the threads and they should go in smoothly.
Step 3: Now would be a good time to solder leads and capacitors to the motors, go here to find out how to solder capacitors to the motors.
Step 4: Attach the bearing blocks to the motors using the 2-56 screws you got. Make sure to use the 2 horizontal holes so that the wheels will be aligned parallel to each other (if you put the screws vertically the gearhead can wiggle back and forth just a little bit, but enough that it could make it not go straight).
Step 5: There should be enough room to stand the bearing blocks up vertically and slide/wiggle them into place between the top and bottom layers. Now mount them in place by inserting and screwing in all the 4-40 cap screws into their respective holes.
Step 6: Now take the LV-MAX Sonar module and solder 4 wires onto it, through the AN, RX, +5, and GND holes. Now find or make a 90 degree mounting bracket for it. I used a leftover piece of Lexan, cut a strip 1" by 2", heated it in a little oven until it was pliable and bent a 90 degree angle in the middle. Then you can either drill some more holes in the bracket, corresponding to the mounting holes in the Sonar module, to mount it; or you can just use some double sided sticky foam; or use Velcro to mount it to the bracket, and the bracket to the robot base.
Step 7: For my Walbot I used old Cpasella wheels and had custom hubs made for them on a lathe. So that means if you get the wheels and hubs from the parts list, your robot will look a little different. If you can find/make lighter wheels with a 3mm bore, I encourage you to do so. Anyway, take the wheel and mount the hub to it with the screws they provide, and then attach that to the 3mm motor shaft using superglue or epoxy.
Step 8: Mount the Arduino board to the top base using the 4-40 screws. If you can get some short 4-40 standoffs that would be best to use, if not just use some washers or a small straw section to raise it off the top base a few millimeters.
Step 9: Attach the 9Volt battery and 2 AA battery holders to their respective places using Velcro. I use Velcro because it is strong yet still allows you to remove them when they need to charge up. The 9Volt should be mounted on the top level in front of the Arduino. The 2 AA battery holders should go behind the motors ( just look at the 3D model in SketchUp to see where everything goes). A quick note on the batteries, make sure that you use 1.2volt AA rechargeable cells (most rechargeable NiMH are 1.2V), if you use standard 1.5volt alkalies that could dammage the motors because they are not rated for 9 volts (6batteries * 1.5 volts =9 where as 6*1.2= 7.2 volts)
Step 10: Time to add the "third wheel" AKA caster AKA half of a ping pong ball or other slick-surfaced sphere thats about the same size as a ping pong ball. Take either of the two things mentioned above and split it in two, you can use your favorite splitting tool be it hacksaw or guillotine... Now all thats left is to fill it with something like hot glue (thats what I used) and stick it to the bottom layer base. You can make out in the picture where I put mine, it doesn't matter really just as long as it provides support for the other two wheels.
Step 11: Pat your self on the back, you're doing a good job, and you're more than half way through. On to the electronics!