Skitter Bot came into this world as result of a chain reaction of exploded of cosmic energy. By current estimates, this chain reaction took roughly 13.7 billion years to complete. When put into such context, it becomes quite clear just how long it takes for near-perfect walking scrub brush bot to come into being.
Do not be fooled. Scrub Bot was not the simple sort of bot that materializes overnight when I zip tie a bunch of scrub brushes together. No! There was an ineffable cosmic plan that led up to this bot's creation, going back well beyond the day when man, through genetic mutation, first evolved the ability to manufacture zip ties and scrub brushes. This bot is a bona fide cosmic child.
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Step 1: Go Get Stuff
(x1) continuous rotation servo modified for direct drive**
(x1) 3 x AA battery holder
(x1) DPDT toggle switch
(x4) scrub brushes
(x1) small plastic container
(x1) ballpoint pen
(x1) 1-1/2" x 3/8" corner brace
(x1) assorted zip ties
**Modify your servos for direct drive here
Step 2: Drill
Step 3: Attach
Next, pass them through the two adjacent center-most holes in the corner bracket.
Then, pass the zip ties through the hanging holes in the brush handle.
Finally, zip tie everything firmly together.
Step 4: Drill
Step 5: Secure
For extra support, zip tie the brush handle mounting ring to the unused back holes of the servo horn.
Step 6: Cut
Trace the outline of the back of the servo and then cut out the shape with a razor blade.
Finally, pass the motor wires through the hole and slide the plastic container lid down over the servo.
Step 7: Drill and Fasten
Zip tie the motor firmly in place.
Trim away the excess zip tie ends if you haven't done so already.
Step 8: Center and Drill
Drill two 1/8" holes.
Step 9: Attach
Step 10: Measure and Drill
Drill a 1/8" hole down through the handle where you made this mark.
Step 11: Attach the Legs
In other words, make two even-length front legs for your bot.
Step 12: Switch
Pass the DPDT switch through so that the shaft is pointing at the scrubber legs and then fasten it on with a nut.
Step 13: Wire It Up
Solder the red battery wire to one of the center DPDT switch pins and the black battery wire to the other.
Turn the switch so that there are only two pins facing you (as opposed to three). Solder the black motor wire to the DPDT pin closest to you on the right. Solder the red motor wire to the other pin on the left.
Note: If, when you power it up, the switch isn't making the motor move back and forth, remove the batteries. Next, detach the motor wires and reverse the switch pins they were connected to.
Step 14: Extender
Step 15: Glue
Fill the pen cap with hot glue and quickly slide it onto the switch's shaft. Be careful not to get any hot glue inside the switch. This could prevent it from working.
Hold the tube in place until it begins to set.