3 Axis skull..where do I begin?

[RosehallManor]

I am thinking about doing a three axis skull on a pop-up skeleton.  I am not sure which controller I should use.  I want to put the skeleton in a casket and have the skeleton sit up and talk .  That is the basics of what I want to do.  I just want to have an adaquate controller.

Thanks

[JonnyMac]

Prop-SX; not as easy as our other controllers, but the only one with the horsepower to do what you want to do -- which is, by the way, a very serious task.

[livinlowe]

RosehallManor-
Jon's right in that this is no easy undertaking. If you go slow, and keep hacking away at it, you can do it. But you will have to learn alot. Probably you should start with something easier, like a pop-up prop, using the Prop-SX to control it. I myself am trying to learn SX/B.

[BigRez]

I too am going to animate a skull and was planning on using a prop-1, but reading the above, I have some questions...

I have the Bucky skull and have already ordered a Scary Terry audio driver and vMusic2 device.  The vMusic device will be driven from a prop-1 with one channel for music/sounds and the other going into the Scary Terry device to move the skull's jaw.  I know these can be used with the prop-1 for a basic skull animation, but was thinking of doing more...

I thinking of getting a pan and tilt mechanism (similar to  http://www.endurance-rc.com/pantilt.html  or  http://www.servocity.com/html/spt200_pan___tilt_system.html ) to control the nod and turning of the skull, and thought that I could do this with a sequencer-type program on the prop-1. (For example, when device is triggered from left or right, rotate skull to the left or right, start an audio track, random nodding and moving skull on horizontal plane, then after x amount of time reset, pause and wait for next trigger.

I figure the sequencer would just define the movements (right, left, up, down) and a randomizer would be used so that the sequence of moves wasn't always the same. Another randomizer would define the amount of time between the position movements.

Does it sound like the prop-1 can handle this?  I haven't used servos before, so can the speed of the servo movement be controlled (slowed/increased?)

Finally, in order to give greater control and synchronization over the movement of the skull, can the servos be driven from software such as Vixen? (Haven't used that yet either, but plan too.)

Thanks all,

[JonnyMac]

Buckies are horrible candidates for this kind of project.  Why?  They're unbelievably heavy and will tear up servos faster than you can say "Boo!"  Some have worked around the weight problem with counter-balance springs but this isn't easy, either.  It would be cool if some company provided a realistic, lightweight skull that could be set up for animation.

You're always going to be VERY limited by the memory of the Prop-1.  If you do a search you'll find "servo blending" code that I've written for it -- you might try experimenting with that for your project (just hook up the servos, deal with the skull later).

[gmacted]

I used Bucky skulls and a Prop-SX for my 3-axis skull project. Here's a link to the "completed projects" section (http://www.efx-tek.com/php/smf/index.php?topic=794.0) with the skulls in action.

There are kits available to make 3-axis skulls.  Check out Graveyardskulls.com (http://www.graveyardskulls.com/)

They sell kits with a different controller, but I prefer the power and flexibility of the Prop-SX. ;D

[JonnyMac]

I guess I'll qualify my comment: buckies are probably not a great choice if you've never done this king of thing before and don't have a lot of mechanical engineering experience.  Many have succeed with buckies, but had to overcome a lot of challenges.

[tds234]

If you have money you can trade this for time and effort. The graveyardmadness kit for the lindburgh skull is probably the place to start. You can drive it with a prop-1 for random movements if you are careful with your code. Much better would be the SX to control the skull and everything else. I have jaw flapper buckys and Lindburghs and I would agree in general that the 3-axis is probably better with a lighter skull rather than the buckys.  Both are certainly doable but I think the lighter skull is easier on servos.

Take a look at this:
http://www.youtube.com/watch?v=2czDZ20sUes
This is daytime video of my haunt with the pop ups and scary terry driver boards(no 3-axis yet). My Mortimer character sits up in his coffin and speaks. His head lolls around for now which I think is creepy lol.

and this shows you the electronic and mechanical elements for each character and the show:
http://www.youtube.com/watch?v=inp0eWLOaJQ

I used a prop-SX to control the whole show and the various audio/lights/pneumatics and distributed scary terry boards to each character to flap the jaws.

This year at least one of the characters is getting a 3-axis upgrade. I plan to add distributed prop-1s or another controller board which I won't name here to run the servos for the characters.

I've already taken the servo blending routine and came up with something similar using a Parallax servopal so that I don't have to worry about the servo refresh but that raises the cost and you still have to compute intermediate positions since the servo's slew at full speed. If you use a servo pal I believe you could get all of it (pneumatic control, trigger for MP3, random skull movement) in a prop-1 but it'll be tight.

In all you are looking at about $300 minimum to use real pneumatics (please do NOT use screen door closers or PVC it's not going to lift what you want to lift and it'll eventually explode), a controller, skull and servos and the other various various bits to build the skull, body and coffin.

I have not used Vixen or VSA to run the routines and the programming time for them is long but the results that I have seen are outstanding.

This is definitely doable. This was my second year haunting but I build all year long.

Freshly Doug

[davisgraveyard]

In my opinion if you have the bucky skeleton already or plan to use one why not use the skull?  I think the alternative skulls placed on a bucky skeleton just don't look right.

With a little work with a Dremel tool and a jig saw you can fashion a perfect working 3 Axis Skull out of the skull on the bucky skeleton.  Just purchase a few parts for McMasters and your local hardware store and hobby shop.   The only real expense are the 4 servos which cost about $15 ea on-line.  And the Prop-SX controller. 

Here is a link to a thread on how I built mine.  http://www.halloweenforum.com/halloween-props/67471-another-3-axis-skull-5.html


You'll spend more time working on the programming than you will building the mechanics. 

[steveo]

I agree with Jon on this. The bucky skull is very heavy and takes a lot more effort to get to work. The Lindbergh skull (in my opinion) looks great on a bucky torso. 20 bucks well spent. If you're not going to do a long routine a Prop2 and vM2 work great for this project. I used nothing but a Prop2 and vM2 for this project. No other power supplies, no VSA, totally standalone.

You can get about 40 seconds of blended 4 servo movement on a Prop2 with room to spare.

The only issue I ran into was power issues from the servos drawing to much. I could have easily powered them independently but wanted to keep things simple. The result was some careful choices in the animation routine to keep the power draw down.

Is it as smooth as VSA? Nope. But it's standalone, cheap and can be done.

http://www.youtube.com/watch?v=fbE5QqtEjWM

[HauntedWolf]

I have not used Vixen or VSA to run the routines and the programming time for them is long but the results that I have seen are outstanding.

This is definitely doable. This was my second year haunting but I build all year long.

I would not try this without VSA...I used Lindberg skulls on dressed PVC frames for mine last year (2007).  I haven't done my videos yet, but I'll post them when done.  I also found a program on Halloween Forum called Parlay that helped a lot.  Between Paylay and joystick capture in VSA it made a fun project.  I used an SX for the controller...loved it!

[RosehallManor]

I have seen the VSA opion, but how or if do I integrate VSA into efx-tek hardware.  I was thinking about using a prop1 to control the casket open and sit up portion.  It would then somehow trigger a second board holding the VSA & MP3 information????

[davisgraveyard]

I used Bucky skulls and a Prop-SX for my 3-axis skull project. Here's a link to the "completed projects" section (http://www.efx-tek.com/php/smf/index.php?topic=794.0) with the skulls in action.

There are kits available to make 3-axis skulls.  Check out Graveyardskulls.com (http://www.graveyardskulls.com/)

They sell kits with a different controller, but I prefer the power and flexibility of the Prop-SX. ;D

Watched your howto video and was wondering if you could describe the ethernet cables you use to extend your servos?  Seems cleaner than servo extension cables.    How did you wire them?

Jeff

[gmacted]

I used Bucky skulls and a Prop-SX for my 3-axis skull project. Here's a link to the "completed projects" section (http://www.efx-tek.com/php/smf/index.php?topic=794.0) with the skulls in action.

There are kits available to make 3-axis skulls.  Check out Graveyardskulls.com (http://www.graveyardskulls.com/)

They sell kits with a different controller, but I prefer the power and flexibility of the Prop-SX. ;D

Watched your howto video and was wondering if you could describe the ethernet cables you use to extend your servos?  Seems cleaner than servo extension cables.    How did you wire them?

Jeff

Jeff,

     Very observant of you. 

     I would be more than happy to share my connection method.

     For the servo control signals, I used some Leviton CAT5 Vertical Keystone Jacks I bought from Home Hepot.  I couldn't find a link on the Home Depot web site, but here is a link to the connectors: http://www.vpi.us/catacc-kjacks.html and a link to the installation guide : http://www.vpi.us/installation/inst-jck-vert.html.  A standard ethernet RJ45 connector has four twisted pairs (8 conductors total) per cable and since each of my skulls had four servos, I used one twisted pair(2 conductors) per servo signal.

     For the power connections, I used two conductor automotive zip cord (http://www.allelectronics.com/make-a-store/item/WRB-20/20-AWG-RED/BLACK-AUTO-ZIP-CORD/1.html) along with standard power connectors (http://www.radioshack.com/product/index.jsp?productId=2103614) and plugs (http://www.radioshack.com/product/index.jsp?productId=2102490).

     I used a dual voltage power supply (+12V and +5V) that had a common ground.  I connected +12V to the Prop-SX and +5V to each skull.  Since the ground (or negative) was common at the power supply, I did not need to worry about having a common ground between two seperate power supplies.

     If you need more details please let me know.

Greg



     

[davisgraveyard]

I notice it looks like you ran a single wire for the power to all servos along with the cat5 cable?   How did that work?

How did you make the connections?  Did you just cut off the ends of the servo connectors and solder them to the cat5 pairs?  Same with the power cable? 

Any chance you could post a closeup picture of the connections?

Jeff