# Gemmy skull-dropper hacks???



## Ryan Wern (Dec 3, 2009)

I bought one of those drop-down gemmy skulls for my garage haunt in 2009. I was wondering if there was a cheap, easy non-midi way to play different audio through the skull and also make the jaw move along with the new audio. Thanks for the help


----------



## fritz42_male (May 5, 2009)

Yes there is.

Most of these props (Talking Boris etc) use a DC motor to pull a string that controls the jaw. My Talking Boris died and I had to sell out good money to fit a servo and a Scary Terry audio to servo driver board to drive it. Not cheap but a good solution.

However, I found a circuit that should work and will be playing with it to drive a couple of Dracula heads I bought cheap. One of the Dracula heads didn't work at all and the other worked for 5 minutes before dying (apt I suppose).

The original hack is here:
http://home.rica.net/jimk/projects/servo/index.htm

But I'm not keen on driving off speaker terminals - I'd rather use a 3.5mm splitter off a standard audio/line signal on an iPod or whatever. Also the existing circuit has no variable controls so I assume that you have to play with the sound volume to get the movement you want - not ideal. Again, I will be looking to work on that side of things.

The new electronics are wired into the motor. It will be easy enough to build a switch in to allow you to switch from internal sound to external.


----------



## heresjohnny (Feb 15, 2006)

I hacked the gemmy skull last year, described in this thread http://hauntforum.com/showthread.php?t=6652&highlight=light+organ Scary Terry has a driver circuit (it is also the first stage of the servo circuit described above) that does a good job driving the Gemmy. There is also a talking fish circuit referenced in there that should work.


----------



## fritz42_male (May 5, 2009)

I'm in touch with Jim Kadel who drew up the original circuit and also came up with the Motor Mouth and Motor Mouth II units. He is selling me an MMII to try (even though he has discontinued them).

I'll report back.


----------



## heresjohnny (Feb 15, 2006)

I dug up the Scarry Terry driver circuit, and the modification I made so it would drive the gemmy skull with the DC motor, no need for a servo, or for an amplified audio source to drive it. One thing to be aware of about the toy motor circuit, you apparently need a good power supply to drive it, batteries don't provide enough current. The original Scary Terry circuit is here http://www.scary-terry.com/audiodriver/audiodriver.htm. The circuit modified to drive the Gemmy skull is:


----------



## Ryan Wern (Dec 3, 2009)

Thanks for the good info. I started messing with the Gemmy skull yesterday. I'm having some success


----------

