Simple Bots: Buck

Just like a bull, a bronco, and a ninja, Buck has a lot of kick. With spring-loaded feet, this noisy little bot does a lot of stomping about. Everywhere Buck goes, commotion ensues. This keeps people on their toes, which is a good attribute for any bot to have.

Check out my book Homemade Robots for more projects!

You will need:

(x1) continuous rotation servo modified for direct drive**
(x1) 4" x 3" x 2" plastic container
(x1) 4 X AA battery holder
(x1) 5" cylindrical metal drawer pull (with two arms)
(x1) 8-32 x 2" bolt
(x3) 8-32 nut
(x2) 4-40 x 3/4" bolt
(x4) 4-40 nuts
(x2) 1/8" (inner diameter) x 1/2" plastic spacer
(x1) 3/4" to 1" extension spring
(x2) 4-40 x 1/4" nuts and bolts
(x1) Assorted zip ties

**Modify your servos for direct drive here

Drill two 1/8" holes opposite each other on the servo horn.

Pass the 4-40 x 3/4" bolts up through the holes in the servo horn.

Thread a nut all the way down to fasten them in place.

Slide on the plastic spacer, and then screw on another nut to fasten this in place, as well.

Lay the drawer pull on its side and make a mark on the top surface 3" from one side of the handle.

Drill a 3/16" hole through the handle in the spot that was marked.

Slide the spring down to the end of the 2" bolt. Fasten this firmly in place with a nut.

Thread another nut half way down the bolt.

Now, slide the bolt into the hole that was drilled in the drawer pull.

Fasten the bolt in place by threading on yet one more nut.

Turn the plastic container upside down. Measure 1/4" up from the container's lip and 2" in from the side of the container. Make a mark.

Make an identical mark mirrored on the opposite side of the plastic container.

Drill both of these marks with a 1/2" spade bit.

Insert the metal drawer pull through the 1/2" holes that were just drilled. The drawer pulls mounting arms should be orientated so that they stick upward out of the containers opening.

The arms of the drawer pull should also be sticking out beyond the opening of the plastic container.

Note: The drawer pull that was used here had a removable arm which twisted off. Being able to take this off, slide it into place and reattach it, made this task easier.

Position the free end of the tension spring such that it is touching up against the bottom of the plastic container.

Flip the container over and make a mark on each side of the spring's mounting ring.

Drill through both of these marks with an 1/8" drill bit.

Using the holes that you have just drilled, zip tie the spring to the bottom of the plastic container.

Place the servo on the inside of the plastic container, next to the drawer pull, in a manner such that the whole motor is on the inside of the container and the bottom of the servo is flush with one of the side walls.

Make marks that line up with the servo's mounting holes and drill them with a 1/8" drill bit.

Using the mounting holes that were just drilled, zip tie the motor in place such that the servo horn is closer to the drawer pull.

The rods jutting out of the servo horn should now be coming into contact with the bolt inserted through to the drawer pull.

Drill a 1/8" hole in a spot on the plastic container where you can pass through the servo's power wires without interfering with the operation of the motor.

With the plastic container still turned upside down, place the battery holder centered atop the container.

Make a mark in each of the holder's mounting holes and then use these as guides to drill two 1/8" holes.

Fasten the battery holder to the outside of the plastic container using 4-40 x 1/4" nuts and bolts.

Solder together the red wire from the battery holder with the red wire from the servo and the black wire from the battery holder with the black wire from the servo.

Zip tie the wires together to make them neater and to separate the solder connections so that they cannot come into contact with each other.

Insert batteries and watch it go.