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Naked Singularity

Latest combat 'bot, planning to compete at Dragon*Con 2012 Robot Battles:
  • Beetleweight (3-pound) weight class
  • Wedge
  • Simple and sturdy:
    • Most parts using standard part sizes to minimize fabrication needs, e.g., internal frame is made from 1"x0.25" 6061-Aluminum bar, which means I only have to cut the bar to length, not width.
    • All critical dimensions are adjusted to multiples of 1/8" to make measurement easier and less error-prone.
    • Held together with machine screws; holes tapped directly into the metal frame
  • Wheels mostly protected from spinner weapons.  Wheel guards have some flex, hopefully to absorb more energy without damaging the rest of the 'bot.  The guards also sit approximately 1/2" away from the wheels to give a buffer zone -- it takes that much more energy for a spinner to actually hit the wheels.
  • 4-wheel drive (separate motors for each wheel)
The guts:
  • Gearmotors: Beetle B16's
  • ESC: Scorpion XL
  • Battery: 850 mAh 11.1-volt LiPo (Power Edge)
  • Wheels: 1-3/4" Lite Flight wheels with Dave's Hubs
  • Tx/Rx: my trusty Futaba 4YF 2.4 GHz Tx with R2004GF Rx
  • Internal frame: 1" wide X 1/4" thick 6061-Al
  • Top armor: 1/8" thick 6061-Al sheet
  • Bottom armor & wedge: 1/8" UHMW polyethylene sheel (used on bottom to save weight)
  • Wheel guards: 1-1/2" (ripped to 1-1/4") X 1/8" UHMW polyethylene bar
    • 1/4" X 1/4" 6061-Al bar used as attachment brackets
  • Fasteners: 6-32 machine screws, Torx drive
    • 3/8", flat head (wedge attachment)
    • 1/2", pan head (most frame and armor connections)
    • 1/2", flat head (a few frame/armor connections where space is tight)
Specs, name, and materials are, of course, subject to change.  :)  With luck I'll do most of the work over Spring Break in a couple of weeks.

Robot Battles 46 Report

posted Jan 26, 2013, 5:06 PM by Lewis Baumstark   [ updated Jan 27, 2013, 6:00 AM ]

Chattacon was a blast this year.  11 beetles and 4(ish) antweights.

Naked Singularity's stats this competition:
Round 1 vs. Chuck Norris: win
Round 2 vs. Shame Spiral: win (plus some very awesome sparking when Shame Spiral got caught in the arena hazard).
Round 3 vs. Pyramid of Death: loss, kicked down to the loser's bracket
Round 4 vs. Churck Norris (repeat thanks to the oddities of double elimination): loss.

Chuck Norris, built and driven by some of my UWG students, progressed to the final, winning the beetleweight class by defeating Pyramid of Death with 3 seconds remaining on the clock.  Awesome fight!  I came in third overall.

The rumble featured all bots from both weight classes.  I placed second, finally getting pushed out after a last-two-men-standing extended dance with my arch-nemesis Wedgie.

Damage report:
  • All four tires, plus my 2 spares, got shredded and/or ground down by the arena hazard.  I love the cost and weight of LiteFlite tires, but perhaps I should investigate another option.  (It appears FingerTech will soon have some minisumo wheels in the right size.  Also, McMaster-Carr has polyurethane rod that could be machined into the proper dimensions, but man it's expensive at about $5 per wheel.)
  • The power switch was acting flaky; it won't always turn on.  Not having power is bad, mmkay?  Investigate battle-worthy options (perhaps the FingerTech power switch, when it comes out).
  • Lots of scratches on the armor, but it held together beautifully.

Dragon*Con 2012 Robot Battles: Microbattles Report

posted Sep 2, 2012, 3:01 PM by Lewis Baumstark   [ updated Sep 2, 2012, 3:32 PM ]

The bad news: Naked Singularity went out in the first round due to poor driving -- I *almost* had him but then messed up and drove off stage.
The worse news: Because of a D*C screwup, Robot Battles had their competition time cut short, so no second match via double-elimination brackets...and no Royal Rumble.  Sad Panda is sad.

The good news: Naked Singularity held up mighty well against a sturdy drum spinner (one based on the Weta kit).  My wedge did exactly what it was supposed to and forced him on top of my bot -- which meant he dinged up my wedge-blade and nicked my front tire.  I'm probably lucky he didn't do more damage to the tire; his spinner was right on it.

There have been times I thought solid top-armor was overkill, but it turned out to be a life-saver here (completely by accident).

Added Some Bling

posted Apr 19, 2012, 6:41 PM by Lewis Baumstark   [ updated Apr 19, 2012, 6:49 PM ]

Naked Singularity w/ Larson Scanner


I did this with a hacked TinyCylon kit from  As you can kinda sorta see in the pictures, I moved the LEDs to a separate board (just a scrap of perfboard I scavenged) connected with a piece of 6-conductor ribbon cable (left over from the Guitar Hero guitar guts I removed to make the Electric Funkatron).  Instead of using the included battery pack, I soldered on the power and ground wires from a servo cable (saved from a gear-stripped servo) and plugged it into an unused channel on the radio receiver.  Which is a weird place to draw power, but the voltage is there thanks the Battery Elimination circuit on the speed controller feeding the receiver.  (I had planned on powering the TinyCylon directly from the FLIP channel of the ESC, but apparently the Scorpion XL ESC does not provide BEC on that channel.)

LED breakout  board and ribbon cable:

Servo cable for power:


posted Mar 26, 2012, 11:21 AM by Lewis Baumstark

Weighed on the school's scale this morning.  As currently configured (new battery, curved rear bumper, etc): 2.66 lbs.

1/3-pound to play with.... oh the possibilitiess...  :)

Spring Break, Day 6: TURBO-CHARGED!!!

posted Mar 24, 2012, 11:05 AM by Lewis Baumstark

The batteries I ordered came in today.  The 11.1-volt LiPo's make the 'bot FAST.  I dig.

Here's a shot of the guts:

Spring Break, Day 3

posted Mar 21, 2012, 12:32 PM by Lewis Baumstark

Mostly piddling around today.  Not much to do on the 'bot until the batteries arrive.
  • Built a wider wedge, one that better protects the front wheels.
  • The pan-head screws holding the bottom armor in place were very-nearly scraping the floor, so I replaced them with counter-sunk flathead screws.  Believe it or not the extra 2 mm or so of ground clearance make a difference!
And then there is this:

In the early design drafts of this 'bot, I was toying with the idea of nearly-360 UHMW bumpers surrounding the 'bot, thinking the combination of curved surface (harder to find a flat spot to push) and springiness (absorb spinner energy) would be an advantage.  I had plenty of 1/8" UHMW left over so I tried a 180-degree version this morning and what you see is the result.  Bonus: convenient carry-handle!

I'm not committed to keeping it yet (I still have the straight side-rails) but I get to ponder it for a while...

Spring Break, Day 2: A Rough Approximation of "Done"

posted Mar 20, 2012, 2:44 PM by Lewis Baumstark   [ updated Mar 20, 2012, 2:51 PM ]

Current weight: somewhere between 2.5 and 3 pounds.  My lousy spring-scale can't do better than that, but either way, I'm good.  If it's on the low end I have some weight to add bling.

It could compete right now.  I finished the other wheel guard, the wedge (don't look too closely...) and got the electronics semi-installed.  The latter are just sort of shoved in without any sense of order or plan.  I'll finalize that part once my 11.1-volt battery packs are in.

I tested it using a 7.4-volt battery I have on-hand.  Once my wife is home I'll have her take a video while I drive.  Everything works great, though it isn't as fast as I'd like.  The higher-voltage battery should help that.

I'm particularly proud of my switch installation.  The next pictures show the recessed slide switch I installed behind one of the wheel guards:

Spring Break, Day 1

posted Mar 19, 2012, 5:03 PM by Lewis Baumstark

After knocking out most of my Spring Break Honey-Do list over the weekend I was able to make some progress today.  I worked on it a little bit over the last week, mostly screwing things up: broke a bolt off in one of the side rails, cut my bottom armor too short, etc.  

After ordering more 1/8" UHMW sheet, I re-cut the bottom armor using the table saw to get the major dimensions and the band saw to do the notch-outs.  So far, so good, with the minor problem that it won't stay flat on its own (it came from McMaster-Carr bowed).  I'm using washers along with the 6-32 machine screws to hold it on.

I also picked up some flat-head M2 screws and the appropriate countersink as part of that McMaster-Carr order.  I replaced the pan-head motor-mount screws with countersunk flat head, giving me more clearance between the wheels and the frame.  Similarly, I countersunk the 6-32 screws that hold the back piece of frame -- the pan-head versions were scraping the wheels.  In retrospect I should have made the frame a little longer in the rear.

I angled off the front "mandibles" in preparation for adding the wedge.  This was more work than I expected.  It turns out our miter saw won't cut an 80-ish-degree angle (as measured from perpendicular to the stock).  The closest it would come was 50-degrees, way too steep.  So I had to free hand it on the jigsaw and clean up with a file.  It looks pretty good.

Finally, I cut some home-made nutstrip out of 1/4"x1/4" Aluminum bar and used it to attach a 1-1/4" piece of 1/8" thick UHMW as a wheel guard on one side.  The UHMW was ripped to width (from 1-1/2" stock) on the table saw.

Hard Top

posted Mar 11, 2012, 3:56 PM by Lewis Baumstark   [ updated Mar 11, 2012, 5:02 PM ]

Top armor cut from 1/8" Aluminum plate.  Got about half of the screw holes drilled and tapped before breaking my only 6-32 tapping bit.  :(

Current weight: approximately 2 pounds.  To be added: bottom plate, wedge, electronics, battery, and wheel guards.

The Lovely Bones

posted Mar 10, 2012, 5:32 PM by Lewis Baumstark   [ updated Mar 11, 2012, 5:24 PM ]

Coming together nicely.  The cross-member on the right isn't actually attached yet -- I still need to drill and tap it.  And one of the gearmotors sits a bit crooked; hopefully I can adjust it a bit.

Update: Yep, just needed to make the indention a little deeper.  That motor (and another that was cockeyed, only less so) have now been set to rights.

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