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I finally had time tonight to take a crack at the Gemmy Crystal Ball (er... Bola De Cristal) that's currently being sold at Ross for $20. This model has Dr. Shivers face and hair. It has prerecorded clips and a wireless microphone but no line in. My goal was to rectify that situation.
Fortune has smiled upon us since Gemmy uses the same basic chassis for a number of different props with separate feature sets. The RF receiver is a completely separate board which makes adding an audio-in jack very easy.
First, here's a look at the box for the Crystal Ball...
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The first step is to remove the globe. There is a single screw on the bottom that you need to remove first. Once that's out simply rotate the globe counterclockwise to remove. With the globe out of the way you should see four screws with integrated fender washers holding down the bottom perimeter of the black fabric. Remove those four screws. You can now lift up the fabric. You can work the two LEDs through the slits in the fabric without having to remove them.
Now it's time to work on the head. Place the prop face down on a towel or blanket. Next locate the two strings which attach the back of the hair to the mask. Cut both strings and fold the hair up and out of the way. You now have to peel the mask of the plastic skull. I used a sharp knife to scrape as I went. This seemed to prevent most tears. There is a fair amount of adhesive and you have to get it all in order to peel back the sides of the mask. Once it's all free, peel back both sides and secure them so they're not in your way.
Looking at the back of the skull you'll see a circuit board. This is the RF receiver. You want to free the grey wire that comes from the top of the head and attaches to the bottom of the circuit board. In this picture, the wire has been unbundled and pulled up through one of the openings in the skull...
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Here's a closer look through the openings in the skull at the board and grey wire...
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Now you have a choice to make. Tap into the audio wire to have both audio line-in and the wireless microphone or cut the wire and just have audio line-in. I decided to cut the wire and remove the board. It's a fully self-contained receiver for the wireless microphone and I know I'll be able to use that for some other prop in the future. Removing the board is easy. Cut the grey (audio) and red/black (power) wires and remove the screw that holds the board in. You can then work the board down and out through the larger openings in the skull. You may have to loosen some of the screws holding the skull halves together for the crystal to clear. Tape off the ends of the power wire just to be safe. Here's a picture of the skull with the board removed and of the board itself...
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Now for the wiring. The grey wire is a coaxial cable with a shield and insulated center conductor. If you're leaving the wireless microphone capability intact you have to be very careful when stripping the wire. You need to strip the outer jacket, peel back the insulation and then work out the center conductor from the braid. You'll then need to carefully strip the insulation of the center conductor too. If you've removed the RF board than stripping and separating the conductors is much easier. You'll need to extend the wire and I recommend using some sort of twisted wire to reduce the chance of interference from the other electronics in the prop. Solder on the new wire and heatshrink or tape up the connections. Route the wire inside the skull and out the bottom to where the rest of the wires converge. I went with an RCA jack but you can also install a 1/8" audio jack if that suits your needs better. I installed mine at the very rear on the side so it comes straight off the back of the base. Here's a picture of the installed RCA jack...
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Now you just need to button everything back up. I used some double sided tape to secure the mask and didn't bother retying the strings for the hair. Feed the LEDs back through the slits in the fabric, tuck the metal ring back into the slots in the base and reinstall the four retaining screws. If you're going to use the globe screw it back on and reinstall the bottom screw.
That's pretty much it! You can now drive the prop with recorded dialog from an MP3 player. Here's the hacked Crystal Ball in action (foreshadowing the future maybe?)...
YouTube - Gemmy Crystal Ball audio line-in hack
If anyone has any questions please let me know!
Fortune has smiled upon us since Gemmy uses the same basic chassis for a number of different props with separate feature sets. The RF receiver is a completely separate board which makes adding an audio-in jack very easy.
First, here's a look at the box for the Crystal Ball...
The first step is to remove the globe. There is a single screw on the bottom that you need to remove first. Once that's out simply rotate the globe counterclockwise to remove. With the globe out of the way you should see four screws with integrated fender washers holding down the bottom perimeter of the black fabric. Remove those four screws. You can now lift up the fabric. You can work the two LEDs through the slits in the fabric without having to remove them.
Now it's time to work on the head. Place the prop face down on a towel or blanket. Next locate the two strings which attach the back of the hair to the mask. Cut both strings and fold the hair up and out of the way. You now have to peel the mask of the plastic skull. I used a sharp knife to scrape as I went. This seemed to prevent most tears. There is a fair amount of adhesive and you have to get it all in order to peel back the sides of the mask. Once it's all free, peel back both sides and secure them so they're not in your way.
Looking at the back of the skull you'll see a circuit board. This is the RF receiver. You want to free the grey wire that comes from the top of the head and attaches to the bottom of the circuit board. In this picture, the wire has been unbundled and pulled up through one of the openings in the skull...
Here's a closer look through the openings in the skull at the board and grey wire...
Now you have a choice to make. Tap into the audio wire to have both audio line-in and the wireless microphone or cut the wire and just have audio line-in. I decided to cut the wire and remove the board. It's a fully self-contained receiver for the wireless microphone and I know I'll be able to use that for some other prop in the future. Removing the board is easy. Cut the grey (audio) and red/black (power) wires and remove the screw that holds the board in. You can then work the board down and out through the larger openings in the skull. You may have to loosen some of the screws holding the skull halves together for the crystal to clear. Tape off the ends of the power wire just to be safe. Here's a picture of the skull with the board removed and of the board itself...
Now for the wiring. The grey wire is a coaxial cable with a shield and insulated center conductor. If you're leaving the wireless microphone capability intact you have to be very careful when stripping the wire. You need to strip the outer jacket, peel back the insulation and then work out the center conductor from the braid. You'll then need to carefully strip the insulation of the center conductor too. If you've removed the RF board than stripping and separating the conductors is much easier. You'll need to extend the wire and I recommend using some sort of twisted wire to reduce the chance of interference from the other electronics in the prop. Solder on the new wire and heatshrink or tape up the connections. Route the wire inside the skull and out the bottom to where the rest of the wires converge. I went with an RCA jack but you can also install a 1/8" audio jack if that suits your needs better. I installed mine at the very rear on the side so it comes straight off the back of the base. Here's a picture of the installed RCA jack...
Now you just need to button everything back up. I used some double sided tape to secure the mask and didn't bother retying the strings for the hair. Feed the LEDs back through the slits in the fabric, tuck the metal ring back into the slots in the base and reinstall the four retaining screws. If you're going to use the globe screw it back on and reinstall the bottom screw.
That's pretty much it! You can now drive the prop with recorded dialog from an MP3 player. Here's the hacked Crystal Ball in action (foreshadowing the future maybe?)...
YouTube - Gemmy Crystal Ball audio line-in hack
If anyone has any questions please let me know!
