Daisy Build Report 3

May 13, 2001

With all the difficult compromises made, and almost all of a long list of small todo items out of the way, Daisy is ready to fight! It has been an interesting experience and we learned a lot! Daisy certainly has weaknesses, isn't stress tested as much as we'd like, and if we had time to start over (haha!) there are some things that definitely would be done differently, but overall we are pleased and look forward to a great party in San Francisco!
 

 
We carefully constructed a self-righting mechanism, which is shown in the picture.  Here's how it works:  a Team Delta "bigger switch" is hooke up into an h-bridge configuration and connected to some limit switches and the motor from a cordless screwdriver.  The output from the screwdriver feeds into a two-stage (13:1 ratio total) chain reduction scheme.  The output gear is then attached to a bar about a foot long.

Worked great! twist a knob on the transmitter and the bar goes up or down on demand!

So we put it in the bot, flipped it over and tried it.

Alas, it is not strong enough.  We figure we need about 400 pound inches of torque out of the final stage and it is only getting perhaps 200.  So, with no time to redesign around a different motor or maybe add another stage to the chain reduction, the whole mechanism went into the box labeled "next time".

bulletThis gave us a couple extra pounds to play with, so we added two things: 
Some little "wings" cut from 1/4 x 1 aluminum bars and bent into shape (not too easy to bend that stuff!).  The purpose of these is to make the bot more difficult to flip over and make it so it cannot be stranded on its sides.
bulletSome lexan over the side armor,  whose toughness had been worrying us a bit anyway.  Plus, the bot came out a tad heavier than we expected so we'd be looking to cut maybe a pound if the self-righting mechanism had worked out.

 
After a paint job and tidying up the wiring, what seemed like a complicated mess now seemed to us to be pretty simple (and with the self-righting gizmo out of the picture more than enough room for everything to fit quite comfortably).

The picture shows the layout.  The very center of the bot is taken up by the EV Warrior motor which drives the spinning weapon via a belt and pulleys.  That motor is powered through a 100 amp contactor driven by a small Team Delta switch and linked to a radio channel so the weapon can be turned on and off remotely.

The left side cheapo drill motors go to one of the Victor 883s, and the right side ones to the other.  These motors don't seem to put much strain on the Victors.

Although because we are a lightweight I don't think we technically need a main power switch, but it is very convenient to have one, so we used a big Hella switch modified slightly so the key doesn't stick out into the air when the bot is powered.  Thanks to Jon, builder of Village Idiot, for this idea.

The radio is connected to three fail-safe units just to make sure that the FM receiver will act predictably if signal is lost, thence into an Ohmark mixer for single-stick control.

 
We put 1/4 lexan on the top (just because it's fun to be able to see inside a BattleBot!), and did a million little things like wiring up an antenna, affixing the vacuum cleaner belts to the tires, zip ties on the wiring, you know the drill.
Then we did some more testing and called it done!
There are still a number of things to be done -- getting a wood block to keep the tires off the ground in the pits, a few minor bolting issues, a little more drive testing (but not too much or too strenuous!  At this point a catastrophic failure would be unrepairable before the event, so we just don't want to know), etc.  Nothing serious.

 
Hope to see you at Treasure Island, it'll be a blast!