# I got my Gemmy Skull MIDI hack working



## Scottzilla (Jun 13, 2007)

I just had to share with somebody. Here's a short stupid video of it:


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## Zombie-F (Apr 12, 2004)

Very nice!


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## NickG (Sep 12, 2006)

hehe, funny stuff.


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## RoxyBlue (Oct 6, 2008)

OMG, that is frikkin' hysterical!


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## hedg12 (Jul 6, 2008)

Oh great, now I'll have that song stuck in my head all day! 

Seriously, that's awesome! I love DMX.

..._I've got a lovely bunch of coconuts_... (wonders off humming...)

(edited to say oops, I meant I love MIDI. I love DMX too, but that's a story for another forum...)


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## Terrormaster (Sep 27, 2007)

Awesome, I always wanted to control them with MIDI, so much potential. The motion is a LOT smoother than with the audio conversion circuits. Not to mention synching up more than just two skulls.

:laughvil: HOW-TO! HOW-TO! HOW-TO! :laughvil:

I got three Gemmy Skulls I picked up this year on reserve 

You and Doc should get together and create a talkin zombie army!


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## RoxyBlue (Oct 6, 2008)

I second the vote on a how-to!


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## Systematic Chaos (Sep 7, 2008)

Where and how does someone begin learning how to do this? I think it's awesome!!! I need something to do this winter.

Well, on a side note edit. I just clicked on the link at the beginning of this thread, lol so I'll start there.


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## halloween71 (Aug 9, 2007)

How to pleaseeee!


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## Dr Morbius (Sep 21, 2004)

Oh yes....this is stuff is right up my alley! I too would like to know more.


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## Frighteners Entertainment (Jan 24, 2006)

Very nice.


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## Spooky1 (Aug 25, 2008)

That's a riot. I need to learn how to do that too. I've already got one of those skulls.


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## RoxyBlue (Oct 6, 2008)

Dr Morbius said:


> Oh yes....this is stuff is right up my alley! I too would like to know more.


I am stunned to think there is anything you don't already know about prop making


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## Bone To Pick (Oct 23, 2007)

That's a gemmy of a tune! Love it!! Please sir, I want more......


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## Dr Morbius (Sep 21, 2004)

RoxyBlue said:


> I am stunned to think there is anything you don't already know about prop making


LOL! I'm glad you think so, but here is a list of tings I don't know enough about yet...

1. Pneumatics. I don't even own an air compressor.
2. Foam latex/silicone casting...Although I learned to sculpt, I have never casted or molded anything.
3. Propx (Prop1 or 2) usage. I have never learned to program a BASIC stamp.
4. MIDI INTERFACES!!!! heheh...Yes, this thread is has peaked my interest to no end!

There's alot more I don't know. I hope to add MIDI to my knowledge base.


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## Systematic Chaos (Sep 7, 2008)

Who else is searching for a Boris now? lol The more I read the more I want. *shakes head*


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## Scottzilla (Jun 13, 2007)

Ask, and ye shall receive. I whipped up a how-to for the MIDI talking skull:

http://www.automat3d.com/electronics/gemmy-skull-midi-hack/


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## Dr Morbius (Sep 21, 2004)

Scottzilla said:


> Ask, and ye shall receive. I whipped up a how-to for the MIDI talking skull:
> 
> http://www.automat3d.com/electronics/gemmy-skull-midi-hack/


Ok, THAT is EXACTLY what I mean by smarter people than me here on the forum!

Dude, that is so KICKASS! I stand up and bow, then applaud, then bow some more. Good thing I bought my son a MIDI capable keyboard. Now a question: Can this be used for multiple (more than two) outputs? I think you said in your tut that there are 12? In other words, can this be used to control 12 seperate switches?


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## Dr Morbius (Sep 21, 2004)

Ok, just had to chime in again...THIS ROCKS! Guys, in case you are missing this, this is a way to control a butt-load of switches with nothing but SOUND! I'm all a flutter..Giddy even.


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## Dr Morbius (Sep 21, 2004)

Systematic Chaos said:


> Who else is searching for a Boris now? lol The more I read the more I want. *shakes head*


There's a similar skull sold in the form of a candy dish. I saw them at Kmart. I'm gonna pick me up one. Or two, if they still have them on clearance.


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## hpropman (Jul 27, 2008)

Nice job Scott. I can also offer a circuit to control a servo through a picaxe microcontroller if you wanted to use a bucky skull with a servo. The output of the Midify board would be connected to one of the picaxe inputs through a resistor and on one of the picaxe outputs you would connect the servo through another resistor. Add the programming circuit if you want (2 resistors and a cap for chip stability). Also two 3 pin connectors and you are all set. you can have complete control of the servo from the picaxe (how far to open the jaw, how long for it to stay open etc..) My sound boards are based off this same circuit. see my website for more information on picaxe chips. One thing I would like to know is that is there a portable sequencing device that can be used lets say in a graveyard that would play the sound file as well as the midi track so that you are not tied to a computer? I know very little about Midi I have been doing a little reading tonight.


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## Scottzilla (Jun 13, 2007)

Dr Morbius said:


> Ok, THAT is EXACTLY what I mean by smarter people than me here on the forum!
> 
> Dude, that is so KICKASS! I stand up and bow, then applaud, then bow some more. Good thing I bought my son a MIDI capable keyboard. Now a question: Can this be used for multiple (more than two) outputs? I think you said in your tut that there are 12? In other words, can this be used to control 12 seperate switches?


@Dr Morbius: Yep, 12 different things. The circuit I drew shows how to connect to a motor or LEDs, but if you hook up a relay coil instead of a motor you could switch just about anything you want on and off.

@hpropman: You could do some pretty powerful stuff with the addition of the picaxe.

They do have boxes that will play back MIDI sequences and perhaps audio too. I'm trying to think of one that doesn't cost as much as a laptop. They also have software that will run on a PDA.


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## Dr Morbius (Sep 21, 2004)

PDA powered props...now that would be cool!


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## Terrormaster (Sep 27, 2007)

Bookmarked and I'll definitely be revisiting this come January. Now to figure out how to control a servo via velocity sensitivity values and use three of the remaining 10 pins to build a 3-axis neck


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## RoxyBlue (Oct 6, 2008)

Thanks for sharing, Scottzilla. This will make a nice post-Halloween project to start working on for 2009.


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## slimy (Jul 12, 2006)

Me too. 

Just beautiful.


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## Terrormaster (Sep 27, 2007)

Scott, I would assume that one could control more than 12 things by putting the Midify controller in omni mode and remapping the outputs to different octaves or putting each controller on a separate midi channel (although I hate wasting midi channels).

I need to learn more about picaxe. 

I really want to control my setup this way in 2009+ cause I was really disappointed with the performance and limitations (or lack thereof) of the audio controllers circuits. I had built two of them, both worked great. The moment I brought them outside they failed. Tested them both yesterday and now they work again. Couldn't be weather, it was 50ish and a tiny bit humid on the big night.


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## beelce (Jul 21, 2007)

Very Very Cool...


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## Scottzilla (Jun 13, 2007)

Terrormaster said:


> Scott, I would assume that one could control more than 12 things by putting the Midify controller in omni mode and remapping the outputs to different octaves or putting each controller on a separate midi channel (although I hate wasting midi channels).


Either way would work. The Midify outputs can be mapped to whatever notes you want, and the whole board can be assigned to different channels. If you wanted to go totally nuts you could run 2048 (128 notes * 16 channels) things off of each physical MIDI port. The challenge there, of course, would be splitting up the signal to all the Midify boards.



> I really want to control my setup this way in 2009+ cause I was really disappointed with the performance and limitations (or lack thereof) of the audio controllers circuits. I had built two of them, both worked great. The moment I brought them outside they failed. Tested them both yesterday and now they work again. Couldn't be weather, it was 50ish and a tiny bit humid on the big night.


Weird. They must be cursed. Yes, definitely cursed. :devil:


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## Terrormaster (Sep 27, 2007)

Scottzilla said:


> Either way would work. The Midify outputs can be mapped to whatever notes you want, and the whole board can be assigned to different channels. If you wanted to go totally nuts you could run 2048 (128 notes * 16 channels) things off of each physical MIDI port. The challenge there, of course, would be splitting up the signal to all the Midify boards.


Actually what I've been toying around with is combining it with a PICAXE. Note 1 would control mouth open/closed, 2 eye lights, 3-8 would control a 3-axis neck, 9-10 an optional 1-axis eyes (if the skull has em), 12 would be neck acceleration on/off (you would hold down in combination with 3-8 to get faster movement - unless you can point me to a board that supports velocity sensitivity).

Or optionally 9-11 could act as a 3 bit binary control which could act as a trigger to 1 of 7 predefined eye routines (roll eyes, look left, right, up, down, dizzy :googly: - whatever you'd write in the code to correspond to the routine #).

Man January ain't gettin here fast enough so it's theory for now... Besides has anyone done a servo driven Gemmy skull yet? Don't think there's room for the eyes and not sure how to go about doing the neck. I'll start a topic for that one.



Scottzilla said:


> Weird. They must be cursed. Yes, definitely cursed. :devil:


I agree and definitely not the only thing that was cursed that night - my ice chest chiller couldn't handle the fog capacity of the 1000w fogger, Media Monkey had a corrupt playlist so I wasn't able to get my playlist going... Despite it all was a great night though. Still annoyed I got ZERO pictures (the good extended aprature kind).


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## hpropman (Jul 27, 2008)

Terrormaster, 

How does velocity output the sensitivity information? Is it a voltage or is it in the Midi code stream? If it is a voltage the picaxe has analog to digital converters that can translate the voltage to a servo position. If it is in the midi code then you might have to make the picaxe bit bang it out of the code. I am sure that we can solve this problem but I need to come up to speed on Midi to understand how it communicates. The picaxe can handle the eye routine selection no problem there. Can we translate the velocity sensitivity info to several outputs of the midify board to act as a binary control? (2 outputs = four servo positions, 3 = 8 servo positions. etc.) Also why does it have to be a Gemmy skull A bucky skull would work also (more room and you would need to add the eyes).


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## Terrormaster (Sep 27, 2007)

hpropman said:


> Terrormaster,
> 
> How does velocity output the sensitivity information? Is it a voltage or is it in the Midi code stream? If it is a voltage the picaxe has analog to digital converters that can translate the voltage to a servo position. If it is in the midi code then you might have to make the picaxe bit bang it out of the code. I am sure that we can solve this problem but I need to come up to speed on Midi to understand how it communicates. The picaxe can handle the eye routine selection no problem there. Can we translate the velocity sensitivity info to several outputs of the midify board to act as a binary control? (2 outputs = four servo positions, 3 = 8 servo positions. etc.) Also why does it have to be a Gemmy skull A bucky skull would work also (more room and you would need to add the eyes).


hpropman,

Velocity information comes in the MIDI stream. To my knowledge on what I know about the Midify board it only looks at the notes and raises the corresponding mapped pin hi or low (depending on the hi/lo solder pad being open or closed), so it's a fixed +/- voltage.

It doesn't have to be a Gemmy skull per se. The main reason really is just that I have about 6 of em lying around downstairs doing nothing and they're super cheap compared to getting a bucky skull all servo'd up.

Another option is to use 8 pins to get a full 8 bits and 255 possible predefined routines that include both eye and neck movements.

Decoding the MIDI stream sounds fun but definitely outside the scope of the Midify board. But I like your thinking.


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## Spookie (Aug 26, 2008)

I bought one of those Gemmy skulls in an after-Halloween sale two years ago at Home Depot. Loved the light up eyes. Haven't known what to do with it until now! Thanks Scottzilla. The instructions look great and something my husband and I can tackle this winter. The price of the board isn't bad either. I have a couple of bucky skulls to play with but the cost of adding everything has kept them in the box for me now.


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## Terrormaster (Sep 27, 2007)

Okies I'm back and resurrecting this post. 

Scott, I know you can control 12 separate things from one board. However I'm looking at power load... Was wondering how many Gemmy skulls could one power off one one +5v suppy and one Midify board? For example, if I had 6 skulls hooked up using two outputs each (eyes and mouth) and they all opened their mouths and turned on their eyes at once. Would say the eyes not be as bright as just one skull having their eyes turned on?

What I want to do is put the Midify in it's own small project box with 6 RJ12 jacks connected to two pins each. Then put the LED and mouth circuits inside the skull and a single RJ12 jack in the back of the skull. Then just use Cat3 to wire it all up making everything modular. Then if I move things around the following year I can always easily extend the distance with an RJ12 coupler.

-TM


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## Dr Morbius (Sep 21, 2004)

I wonder if the PropSX can handle MIDI data?


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## Scottzilla (Jun 13, 2007)

@Terrormaster: Power-wise you are limited by the power supply you are using. The Midify board only has to be able to provide the gate current for all the transistors, which is very small. Each transistor only needs to handle enough current for the individual LEDs or motor it is controlling. If you turn everything on at once your power supply has to be beefy enough to handle the full load. Also make sure you use decent sized wire. If you do that the eyes shouldn't dim.

BTW, Midify is decoding the MIDI data, but it only uses it to turn outputs on and off. It discards the velocity information.


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## Terrormaster (Sep 27, 2007)

Ah ok, so really depends on how many amps my supply puts out then.

Question. If I'm splitting the circuit in your how-to into something a bit more modular I'm trying to figure out which end of the modular circuits the 10uf capacitor would go.

Essentially here's what I'm planning:

Inside each skull would in theory be the following board:










Then an RJ12 jack would be wired as follows:

1. +5v
2. Gnd
3. Control A - Mouth in
4. Control B - Eyes in

On the other end would be a Midify board in a box with 6 RJ12 jacks out. The note pins would be mapped to RJ12 pins 3 and 4 in even/odd pairs (1-2, 3-4, 5-6, etc).

I'm familiar with the circuit in the skulls as it is almost verbatim the circuit found in the motor mouth controller I used last year.

I'm just wondering if the capacitor should go with the Midify box side or have one on each board in the skulls? I'm thinking it would go with the Midify side since I only saw one in how-to picture where it controls two skulls. I'm pretty certain that would be right but want to make sure.

The idea here is to build a module design where I can build custom controllers for the skulls on an as needed basis without having to open up the skulls and remodel their circuits each time.

Thanks,
-TM


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## Scottzilla (Jun 13, 2007)

The capacitor is for filtering the power supply. Without it you get weird things like brownouts causing the eyes to turn off or the mouth getting stuck open. I would imagine that you just need one near the Midify board, but if after you build your circuit you have these types of problems then just add one on each of your boards.


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## Terrormaster (Sep 27, 2007)

Scott, what's the best method for hooking more than one Midify to a PC?


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## Scottzilla (Jun 13, 2007)

The easiest way would be to pick up one of those MIDI thru / splitter boxes. If you want to do a little soldering you can build one fairly easily too.


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