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Toxic Asset

A 3-lb combat robot, really just an update to upChukk with the following mods:
  • new motors (actually, motors scavenged from Chili Fixins)
  • better armor: 3/16" 6061 Aluminum
  • hardened weapon shaft
  • possibilities for new weapons: mini saw blade, mini grinding wheel.  (I found these at Harbor Freight; they have 1/4" bore -- which matches my current shaft setup).
  • horizontal saw blade (it just might happen, folks!)

Spare Parts

posted Jan 2, 2012, 5:18 AM by Lewis Baumstark

I've had some trouble with the Fingertech Gold Spark motors -- one of the original three I ordered last year stripped its gearbox, so I ordered a spare set of the Fingertech Silver motors in the same gear ratio.  The description says they have beefier gears, so here's hoping.  I may or may not install them prior to the competition, but I'll have them in just in case.

Also ordered a spare set of wheels, since in the new design they are more exposed -- and more vulnerable to spinner weapons.

Coming along nicely

posted Dec 19, 2011, 11:31 AM by Lewis Baumstark

Back view showing a close-up of the saw blade:

Top view showing the saw blade and front pushbar/shovel-thingie:

There is a power switch accessible from the scoop-side, just under the "Power" written in sharpie.  :)

Still to-do:
  • trim long bolts so I can truly be invertible
  • shave 4 oz or so off the weight
  • fix my offset wheel issue (one is 1/4" farther back than the other!)
  • paint? stickers?

Repurposed Hard Drive Motor

posted Dec 17, 2011, 7:45 AM by Lewis Baumstark   [ updated Mar 25, 2012, 10:04 AM ]

At one point while building upChukk, I toyed with using a hard disk platter motor to power a horizontal spinner weapon (e.g., small saw blade).  It had a lot to recommend it -- low amps, flat profile, and a arbor that perfectly fit the jamb saw blade I bought at Home Depot.  At the time, though, I knew nothing about brushless motors and eventually gave up on that line of inquiry.

I've come back to it now after learning enough to be dangerous.  I managed to accidentally buy a brushless ESC (I forgot to check its ampere rating before buying and it turned out to be too low for the particular motor I intended) a while back and realized it would probably drive the hard disk motor.  So behold my experimental setup:

The components:
  • R/C receiver (black box, top left)
  • R/C transmitter (not shown)
  • hard disk motor (silvery circle)
  • 30-A brushless ESC (yellow thingie in the middle; yes, I know 30-A is WAY more than needed here, but I already had it)
  • 7.4-V LiPo batter (black box with "PowerEdge" on it)
Using this setup I was able to control the motor speed with the transmitter.

The biggest question mark was that the motor had four solder pads (see next pic) -- but a brushless motor only needs three for signal.  One of the reasons I used a terminal block to connect the ESC and motor was I needed a quick way to test out which pads were the correct ones.  The terminal block would let me re-arrange connections easily until I found the right combination.  Ironically I hit it on the first try.  :)

(My best guess as to the fourth solder pad is that it's for bleeding off static that builds up as the platters spin.  Static and hard disks are bad, mmm-kay...)

Finally, a pic with the saw blade attached:

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