Construction of the Choir - More

 

Orthopedic Lobster Surgery

The lobsters on the hood are not made of the finest material. We had to skin them and perform preventative surgery to reinforce certain of the plastic parts with epoxy putty. Time will tell whether this will stem the alarming breakage rate. (Note: It didn’t. We later ended up machining aluminum replicas of the offending part - orthopedic hip replacement.)

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Here is a picture after we performed orthopedic (aluminum) hip replacement on the lobsters:

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The Soloists

For the 2001 parade we primarily worked on mounting fish and lobsters along or above the car surface. However, from the very start the design called for having soloists that could rise up from the car to sing certain parts while the general fish would be choreographed separately to sing the chorus. To this end we left a ridge of empty space along the roof of the car.

In 2002 we added risable soloists, but unfortunatly they didn't really look like soloists, being made of standard garden variety Billy Bass. So the effect didn't really work that year. I was begining to think we would have to make soloists from scratch, which is a problem since none of us are, technically, artists. However in 2003 we found that Gemmy had come out with "Billy Bass Superstar" which is a fish standing on it's tail singing into a microphone (which it can wave back and forth by the way.) Perfect!

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The Choir now has a male soloist and a female soloist under independent computer control allowing choreography as complicated as we care to make it. Each soloist platform can raise itself about 2 feet above the roof to really stand out when it's time for it's part. The platforms can rotate back and forth, the fish can wiggle as well as sing, and (when working) they can wave their microphones. Here are two pictures of the male soloist in lowered and raised positions respectively.

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The soloists are lifted by a simple screw drive mechanism using surplus 12V DC reversable motors, a threaded rod, and an aluminum "parallelegram" lifting frame I made from scratch. Springs are used to counterbalance the weight when the platform is in "down" position. Power to the lifter motors, and to the reversible motors that turn the soloist platforms, is provided by DPDT relays arranged so that they can supply polarity reversal when needed. Limiter switches are used so the motor cannot continue pushing down after the platform hits bottom, nor can it continue lifting when it hits top. That alleviates the need for sensors to tell the computer what position the platform is in at any given time. (I later added warning lights inside the car to tell me when the platform is extended, after I accidentally drove into a garage with the soloist up and decapitated the poor fish. Fortunately it broke cleanly and was fairly easy to replace.) Here's a picture of one of the lifter motors on the roof, and the relay driver box in the trunk.

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The Conductor

The Conductor is an extemely popular and fun feature of the car. He zooms out from the roof of the car on an extendable boom, waving his baton to the music as he rotates from side to side. We call him "The Lobster Formerly Known As Larry."

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The Conductor was the only major feature of the car not conceived in the first few hours of brainstorming back in 2000. It was 3 months into the project that I realized every orchestra needs a conductor. Original designs called for an octopus with multiple batons on a lift platform similar to the soloist lifters. An immediate problem was finding a large rubber octopus we could articulate. One would think they would be for sale everywhere, but googling "Giant Rubber Octopus" leads one to innumerable retellings of the Bela Lugosi/Ed Wood story, rather than anyone anywhere actually selling a rubber octopus.

So the conductor was deferred while we worked on other things. However, about that time I was also planning my wedding to the beautiful and talented Alison Prince. It occurred to me that, properly programmed, the car would make a great Best Man. But it needed some way to hand me the ring at the proper time. That's when I started working on the extender boom. I later realized the boom was perfect for the conductor, so the two projects merged. We never did find an octopus, but Larry auditioned for the Conductor role and won.

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Building the slide itself wasn't too hard. I took 6 telescoping drawer glides, and bolted them together, grinding the bolt heads down when needed so nothing would snag. When retracted the conductor is right at the front of the roof. When fully extended he's 6 feet further out, even with the front bumper so he can poke spectators in the eye with his baton if he so chooses. Ted Nussbaum, another one of Team Sashimi's heros and our only certified EE, put together the rotator platform.

Here's a photo of John working on the rotator platform.

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Getting a mechanism to actually push the slide out and retract it was much harder. I messed with different designs sporatically for almost a year and almost gave up on the whole conductor concept several times. John wanted to try pnuematics but was so busy with the car electronics and new sound system he never had time to prototype anything. At one point I decided that the "easiest" approach, and one with a perverse attraction, was to use rocket motors to extend the slide. (We'd have to jump out of the car and pull it back manually afterwards, and could probably only use it half a dozen times per parade, but what the heck?) So over several weekends we did experiments with successively larger and more numerous model rocket motors attached to the slide mechanism on a testbench in my back yard. We never did find motors large enough to extend it more than a couple of feet, but we do have wonderful video of the tests. Everyone would don safety goggles and assume serious expressions, we would have the traditional countdown, and then Whoosh! Lots of smoke and little action. Although when the parachute-ejector-charge went off in the rocket motors a few seconds later, there was always excitement as people hopped to get their feet out of the way of the spent motor casings bouncing around my deck.

I finally concocted a system with an aluminum push-rod running the length of the car roof, attached to a loop of #25 chain (like bicycle chain but a bit smaller.) The push rod was guided by a channel which (after much fiddling and modification) kept it aligned and prevented the mechanism from jamming. The chain loop extends between a free-spinning gear at the front of the roof, and another at the back. In the center of the roof the chain is driven by a 12V reversable motor. The first design used an old weedwacker motor. When we eventually burned that out, I replaced it by a humongous surplus motor originally used in electric bicycle-scooters. There were some other design problems but eventually the conductor worked! Occasionally. The pushrod still jammed often, the connector between the rod and chain tended to snap, the thin-wired electrical coil-connector to the conductor tended to break, the driver gear does NOT want to stay attached, etc. We first showed it in the 2002 Houston parade, where it was functional about half the time. But we've tweeked it now so it has about 90% reliability on any given day.

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Above is the driver motor in the center of the roof. The dull-blue rod to the left of the sprockets is the push-rod. Below is a picture of the free-wheel chain support at the end of the roof. With close examination you can see the push-rod attached to the chain. The "T" to the left is the spring-anchor for the rear (female) soloist lifter mechanism.

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Oh, so you've been waiting to discover whether the car really was the Best Man at my wedding. Hmm, I would THINK you would know the answer to that by deduction using universal first principles. :-)

Being a clever fellow, I decided to first present my fiance with a less palitable choice, and then let her talk me down to the "Best Man" concept. So, first I had the car ordained as a "Minister of Music" in the Universal Life Church, so it can legally perform weddings in Texas (just like most of the rest of us.) Then I suggested that not only we get married in the parade but that the car be our minister.

What can I say? Women are weird. So far the car has never actually performed a marriage ceremony, and my buddy Boston Dave had to fly down and be my best man. :-)

We settled on John as our minister, and if you ever meet him, ask about how it felt to be kidnapped and delivered to the marriage ceremony in a straight jacket. (I refused to tell him in advance which weekend he would have to perform the ceremony, as a courtesy so he would't angst, and just sent my grooms to forcibly collect him when it was time.) "Minister Delivery" was the explanation given to the folks working the front desk of the Four Seasons. But, I digress. We were discussing cars.


The remainder of this Page on the construction of the Choir is (ahem) Under Construction (Sorry)


Computers

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The Big Bass

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The Heartbreak of Fishcar Maintenance

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Flags

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Click on any image to get larger version. 

Topics to add:

Computers (Basic Stamp BSP40, and Linux Laptop)
Choreography
Conductor
Soloists
Big Bass
Repair and Maintenence