I helped my friend Andrew Kuttig, in Colorado build Casanova, as plagued with trouble as this bot was it was also a lot of fun to build and run. Casanova uses a hammer mill design to pummel its opponents into pieces. while the weapon itself is formidable its power supply and drive train turned out to be lacking in strength.
If anything where this bots drive train, power, control, maneuverability all lacked it was a great proof of concept for the hammer mill design and a fun learning experience with spin bots.
This spin bot is designed around two large hard disk drive platters sandwiched together with all the guts in the center. The hammer mill is attached to the spinning top platter that is direct gear driven. This bots design is testament that with only a hand drill and good measurements you can build a centrifuge from scrap parts, I was fairly shocked just how smooth this bot spun at extreme high speeds with very little wobble, some how we balanced things out nearly perfectly.
Casanova is a tether bot which due to design faults cause its own problems, My friend was a bit of a computer tech head and decided he really wanted to use Cat 5 cable as his tether cord, I had my hesitations that it would not be flexible enough and I had worried about the brittleness of the thin copper wire inside. he really wanted to use the stuff and it was his bot... so I bent. in the end the Cat 5 turned out the be even more brittle than I had guessed and plagued this bot with glitchy controls. Surprisingly I had also guessed that by its nature the tether would frequently get tangled in the hammer mill. however after multiple runs to my surprise we where able to keep the cord out of the mill most of the time.
I helped him build this bot at the same time that I was building Black Dog, unfortunately this bot used two of the same slow Tamyia worm gear drive in a tandem tank drive style. This made the bot slow with plenty of torque, unfortunately its traction sucked so very little of that torque actually mattered. I think this bot would have rocked with a little more traction and a faster gear set.
We fell a little short on time and the bot was having trouble with the 2lb limit so we regrettably skimped on the power supply, both drive motors and the bots hammer mill where all powered off of a single 9v battery. Surprisingly this did power the bot for about 3 min just long enough for a round of battle, but if the fight was not over quickly you could see it getting sluggish after 2 min. this bot went through a lot of batteries. With more time I would have cut a lot of material out of the lower platter and added a standard AA or AAA rechargeable battery pack.
The hammer mill itself ran perfectly, even though it was direct gear driven. I had mounted the drive motor on a riser that was slightly flexible I believe this saved the gears and allowed for after combat re adjustment if anything got bumped out of place. This hammer mill did about 80% of the combat damage black dog took while most of the damage on black dog was cosmetic some of the other bots that took solid hits did not fair as well. if this bot would have been more maneuverable it would have increased the effectiveness of the weapon 10 fold.
Hammer mill basics:
A hammer mill works by holding weights or hammers on a freely rotating joint on the outside of a rotational circumference.. centrifugal force moves the hammers to the farthest point away from the center of the rotational axis as possible. The hammer stays there until impact, at impact the hammer transfers its momentum energy into the other bot making a solid hit however the hammer itself reacts to the impact in that it rotates away from the hit allowing the main disk to keep spinning. by the time the main disk has gone full circle the hammer is outstretched again ready to impact again. This "hammer mill" allows for multiple impacts from one hit and keeps the main disk spinning so that there is no spin up time after each hit. The main disk does lose some of its momentum and slows down after multiple hits but since it never fully stopped spinning its faster to get up to speed again, it never stalled out saving on battery life, and it never transferred the impact energy into its own gear drive. Hammer mills do not hit as hard as single hit solid hammer spin bots but if done right the fact that they hit multiple times with one attack makes up for this fact and then some. The rattling vibration of getting hit multiple times in a row in quick repetition can knock parts off of some bots without even hitting that particular part.
I fully expect to build another bot like Casanova at some point with what i learned from this bot. Hammer mills have great damage potential if implemented correctly.