Bot Blast Recap

So, Bot Blast happened, and it wasn't a complete failure.

Actually it was, but it was a highly entertaining failure.  In the week hours before we left for PA, Jaguar and Dane also managed to whip together some little antweights.  I finished a little early, so I did some weapon testing on Jaguar's in-progress bot.



Here's the trio of last minute bots.  Mine on the left, Dane's stepper motor powered Del-Ran Bumble in the middle, and Jaguar's Speed Bump on the right.

Picture credit to Charles

My first match was against Dust-Pandemonium, a dustpan shaped robot with a blender-like attachment in the middle of the pan.  It became immediately apparent that my robot was just way too slow.  I just could not move fast enough to do much of anything.  My opponent even had some sharp corners and exposed wheels that my recessed spinning drum could have easily bit into, but he outmaneuvered me by a mile.  Fortunately, his weapon was more for show than destruction, so all it did was put some scratches on my steel drum and carbon fiber armor.

My second match was against Fire Arrow,  a simple but very effective wedge robot.  It was much faster than mine, and even more importantly, had a really impressive driver.  Neither bot took any damage, but I was outclassed, and voted the loser by the judges.

The competition was double-elimination, so I was out.  Maybe next time I'll start more than five days before the event.

One-Week Battlebot Blitz

Sometime in the early hours on Monday morning this week,  I decided to join Charles, Dane and Jamison on an adventure to Bot Blast 2013.  Problem:  I do not have a battlebot.  So I had roughly five days to build up a 1 pound battlebot from scratch.    I came up with the rough design for a robot with spinning drum weapon, and then just built the drum so I had something to design around.

The drum was made from some steel tubing.  It's driven by a small brushless motor I scrounged via a press fit aluminum hub:

I scrounged some tiny gearmotors and grabbed one of my spare quadrotor batteries:

Starting to look like a robot

I turned some very shiny wheels out of 2" aluminum round stock.  The tires are made from short segments of bicycle inner tube.

As a backup defense mechanism, I made the non-attacking side of the robot wedge-shaped.  The tip of the wedge was milled from aluminum, using some very sketchy clamping techniques:

The rest of the robot's shell is carbon fiber.  Because of the robot's wedge-shape, I named it "A Glorified Doorstop."  When it fails miserably as a robot, you know how I'll use it.

To actually hold all the parts inside the shell, I laser cut a Delrin frame.  The motors are press fit into 3D printed mounts, and the drum rotates around a pair of low-profile bearings on the outside of the drum.  I put the bearings on the outside, because I could not spare the weight for an axle about which the drum could rotate.

The Delrin pieces were edge tapped and screwed to the carbon fiber.

So the spinning drum could catch opposing robots, I added some flat head socket cap screws around it. They thread into an aluminum nut strip on the inside of the drum.

Electronics were pretty straight forward.  An RC receiver feeds signals to a Turnigy Plush 6A brushless controller for the weapon motor, and two VEX 29 controllers for the DC drive motors.  For some unknown reason, I was unable to get the drive controllers working on a 3S LiPo pack (11.1V), so the robot is painfully slow.  I think the issue is probably with the brushless controller (which provides 5V to the receiver), since it's really only meant for 2S batteries.

And some pretty pictures:

An event report will follow.  If only its destructive abilities matched its good looks...