Thread: 3 AXIS SKULL Rock Band Braintrust - Designers colaboration

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I'm Starting a thread for us 3 Axis Skull guys that are actively creating Rock Band animation for our Halloween Displays.
The intent of the thread is a collective sharing how-to similar with the thread we have creating the command centers for our 3 axis displays. I plan on documenting my entire build for the benefit of other forum members as well as hoping to pick up suggestions from other builders with similar interests.

Introductions First:
Bart Gaffney
aka Black Heart Bart
aka Sadler Vampire ( Halloween Forum member since 11/2007)
aka Bart_at_Haunted_High ( Society of Robots Forum )
Builder (12) 3 axis skulls for "Stage Fright" at Haunted High 2011

Project:
Repurpose present configuration to a Rock Band with:
(1) Lead Guitar ( Singer )
(1) Rythme Guitar ( Singer )
(1) Keyboard Player ( Singer )
(1) Bass Guitar or Stand-Up Bass ( still undecided ) ( Singer )
(1) Drummer playing a 5 piece standard set ( may grow to a larger set ) ( Singer )
(3) Back-up singers ( female Vocals )

Design considerations for Guitar and Players:
a) Hand movement up-and-down guitar neck
b) Arm Strumming
c) wrist picking
d) Axially rocking up and down slightly of guitar with rear pick-up as aprox location of CL of axis
e) Torso Twist side to side of Figure

Design considerations for Keyboard and Player:
a) Hand movement side to side along keyboard
b) arm ( elbow ? ) movement up and away from keyboard and back again to keyboard

Design considerations for Drummer :
a) Torso Twist side to side of Figure
b) Sholder, Elbow movement ( both arms ) general placement to drumset components
c) Wrist Movement ( drumstick up and down )


Design considerations for control and programming:
a) Programming using Brookshire VSA
b) Servo Control using Lynxmotion SSC-32 Boards

Project Deadline: September 2012

Let the Fun begin.....

This will be fun! I'm looking to do something like this as well.

I'm in - thanks for starting this.

omg this will be kewl!

amk

I guess I will be the last to post on my band improvements as it was the first to be stored so it will be the last to be pulled from storage. Which really sucks as I needed to make the arm movements better. We better keep our eyes out for Halstaff. While we are running RJ45 wires and such from our computers to the skeletons his will be self contained and running picaxe. One little chip will probably be running the whole band. Give me a couple of months Halstaff and I will be firing questions to you about picaxe. Really like the idea of having a self contained unit.

Hey, I'm new on this forum, but we just finished doing a skeleton band this year so I thought I'd pass on a couple of things that worked for us.

For the two guitarists we decided that having them being able to windmill strum ala Pete Townsend was inviting disaster - our arm animatronics just aren't that perfect. So we carved hands that could hold a pick, and locked them in place on the front of the guitar in picking position. To get picking/strumming motion, we mounted a servo on the back side of the guitar with a piece of 4/40 threaded rod centered on the servo. A hole was drilled in the guitar and the rod came through to the front and was attached to the back side of the strum hand wrist. When the servo turned, the rod turned and the hand pivoted up and down. This worked really well and gave us very realistic strumming motion.

For moving the other hand up and down the neck we attached another servo to the back of the guitar body and put a fairly long T horn on it. The two ends of the T horn were attached to a piece of string that went through a screw eye and then all the way up the back of the neck of the guitar to a pulley attached to the back of the headstock. The fret hand was carved to hold loosely to the guitar neck so it could slide back and forth. So one of the strings was attached to the back of the hand, behind the neck, and when the servo pulled the string back and forth the hand moved up and down the neck. This worked moderately well...mostly due to the hands being a little bit too tight on the neck and us not having time to carve new ones.

My favorite thing though was the bass players strum hand. I had picked up some of those crawling hands...you know, the battery powered ones that are just a hand with a little bit of the forearm and when you turn them on the fingers pull the hand along the ground? We mounted that on the same servo strum rig but also hacked the motor in it so that we could selectively turn it on and off with a relay driven by VSA (as was the whole show). So the bass player plucked his strings instead of strumming, but we could still pivot his hand up and down so he could pluck from low E to high whatever.

We've had shoulder turn and lift plus elbow for a bunch of years on all of these guys so I just used those servos to help throw the guitar around a bit as they were playing. Since the hands were locked on the guitars I could be fairly brutal with the arm servos and the hands didn't come off. It looked pretty great - but it broke the drive strings for the fret hands a couple of times and we lost one servo. C'est la vie.

I know, a picture is worth a thousand words, but I don't have any pics of these build details and the skels are in storage, I'll try to get them out and get some pics up. Here are a couple of pics of the show though:





We do have video, lots of it in fact since we were running a live switcher feeding a 9x12 screen over the stage. I just haven't had time yet to edit it down so that I'm happy with it.

In closing (formal, I know), I've lurked here on and off for a bunch of years but I think this is the first time I'm contributing. Nice to meet y'all...and BTW, the reason I'm on here today is that I'm looking for a way to make 3-axis skulls for next years show. And I found it! So yay and thanks to Halloween Bob for starting that great thread that I've read almost all 200-some pages of. Next year we'll have more than just nod and jaw!

Later,
Chris

skeletontheatre.com

Okay, I was able to get out to storage this morning (had to get some Christmas decorations) and was able to grab some gear to explain with pictures what I was muddling through last night. I'm sure people will come up with cooler, better, faster ways to work their guitars, but this worked for us.

First, the back of Nero's guitar



The servo you can see is the strum servo. Underneath the black shield is the fret hand servo, more on that in a bit.

Here's a closeup of the strum servo



And here's an extreme closeup. This shows how we used a piece of 1/8" thick by 1/2" wide aluminum to double back and center the 4/40 rod directly over the center line of the servo gear.



Here's the underneath side of Nero's strum hand



And here's the top of that hand. You can see the two screw heads that are holding the carved hand to the piece of aluminum underneath that's attached to the threaded rod.



Here's the fret hand servo.



This was underneath the shield, which I've removed. The plexi disc was our first try: if the string was wrapped around the disc (which was grooved on its outside edge) then we got more string travel for 180 degrees of servo travel. Unfortunately the string kept slipping off the disc then we'd be dead in the water. So the quick and easy fix was just to drill two holes in the outer edge of the disc and run the string through them. We were basically just extending the servo horn to the sides with a very pretty machined disc.

The shield was over the disc because the back of the guitar rested (and banged) on the front of our skeletons. Without the shield protecting the servo, the skeleton's body would have negatively impacted our fret hand travel. BTW, we routed out the back of the guitar body so that we could sink the servo down into it as much as possible - we didn't want the guitar to stick out too far from the body of our skeletons.


Here are the two eyebolts used to get the fret hand string down to be snug against the back of the guitar neck so that it would be hidden.



And here's the back of the headstock where the pulley let the string turn around



Here's the back of his fret hand, where the string ties on



And the front





Here's Baßgeige's (bass player) strum hand



And a detail pic of how it's attached to the strum servo



His fret hand was very heavy, so we had to make a couple allowances for that. On the back of the bass neck we mounted a drawer slide. The string pulled the slide back and forth and the hand was attached to the slide.



It was still too heavy though, so we took the E string off, ran it through a small metal tube and then epoxied the tube to his hand. A little teflon spray helped lube the tube.




We used a full sized bass, because that skeleton was a little bigger, but full size guitars would have dwarfed our other skeletons which are only a bit over 4' tall. So we used kids guitars for them. The only problem is that those kid guitars tend to have little speakers and led's in the front that scream "toy". Here's how Nero's guitar looked before we modified it.



The simple solution was to take the speaker out, copy the template for a pic guard from a telecaster, cut it out of white plastic and put it over the hole. We actually prepped a total of 4 guitars for the show, though we only used two. Here's my favorite transformation, flame guitar before:



And flame guitar after (with the rest of the show guitars)



And finally, from the show footage, here's Spur (lead guitarist) with his main axe



And our bass player, Baßgeige Speilsachen




Oh, one last thing! We got all of the guitars through Goodwill's online auction store, which is a great resource. Google "shop goodwill" and you'll find it. Watch for shipping, but it's usually pretty reasonable, and if you're lucky one (or more) of the participating goodwills will be close enough that you can pick stuff up in person. This site kicks the pants off of ebay for price if you can find what you want.

I hope this doesn't count as hijacking your thread, it wasn't my intent...I figure this is pretty on point for what you want to do next year. Hopefully it can help someone.

Cheers,
Chris

Awesome work, Chris. How much travel up and down the fretboard were you able to get with that setup? Would love to see the videos - thanks for jumping aboard!

Thanks for the welcome! The fret hand setup as it is now gives me about 4 inches of fretboard travel, which isn't much, but on the small guitars it reads okay. One of the things I absolutely would have done if we'd had time is make bigger horn extensions for more travel.

I realized that there was a video I could post that might be useful. Though I'm still waiting on all of the footage that was shot this year before I edit down the "live" performances, there's a test vid I'd made of Nero playing his guitar right after I first hooked him up to it. This was before I got the real hands, so I'm still just using the blow mold hands he came with. He's the rhythm guitar player so his strumming action isn't as detailed as Spur's was. Oh, and this is when the string was still looped around the plexiglass disc, so the fret hand travel is a little bit more than what we ended up with in performance.

CRWsound, I am in awe... That is GREAT and I only wish that I had seen what you did before designing and possibly overdesigning. I have a crapload of stuff here and more on the way from Servo City. To paraphrase I'm utilizing the standard servo sized servoblock and hub design offered by servo city to take some of the strain off the servo, Were using heavier servos for the Guitar neck hand. Target movement is 11 inches on a full size guitar accomplished by driving a 9" sprocket and 1/4 inch chain drive which loops up to the guitar neck headstock. We are also using a slider bolted to the back of the guitar neck. I have desihn illustrations and will begin loading photos of the build in the comming weeks. I also purchased a 5 piece drum set and will be looking to automate that as well.