Skeleton hologram activated by doorbell…

Welcome to Holo-ween!   Here’s a fun hologram project that we’ve been meaning to do for a long time for Halloween, and it actually turned out to be much easier than we expected.

This is a 4″x5″ hologram of a skeleton in a coffin.  But the best part is that everything is activated by a standard doorbell switch, which not only activates the laser illumination, but it also has a great thunder sound effect and flashes the laser light to look like lightning flashes!

And the best part is that we did everything with off the shelf components, and it took us 1 afternoon to put everything together!  All of the components for this project are listed at the end.  You will need our LitiHolo Hologram Kit, and the 4″x5″ Hologram Upgrade Kit, but additional parts beyond this cost us about $19 plus some AAA batteries for powering the thunder/strobe unit that we got from Halloween City.

So let’s start first with the hologram-making.  We started with the subject for our hologram, a great looking skeleton from Michaels and a simple paperboard coffin that was about the same size, also from Michaels.  We did have to remove the skeleton’s arms to fit him into the coffin (he didn’t mind), and then positioned the coffin sitting up on the table and leaning back against the wall (you could prop it up on something else, or hot glue it to something for better stability).  The skeleton’s legs were sticking out the bottom of the coffin, but could have been removed as well.

The 4″x5″ hologram plate was going to be positioned with the top edge lined up with the top of the coffin.  We wanted the hologram to focus on the head and rib cage, which looked amazing when lit up with the laser light.  To hold the film plate, we used small binder clips attached to the sides of the coffin where the bottom of the film plate would rest.  It’s helpful if you let the binder clips stick out a little, to give a nice ledge for the film plate to sit on.  Because the coffin is sitting back at a slight angle, the film plate rests on the binder clips, and just leans back against the coffin during the exposure.

For the hologram lighting and exposure, we used “under lighting” which gave a cool spooky lighting, but also allowed us to position the laser below the hologram right on the table.  The laser from the 4″x5″ Hologram Upgrade Kit was oriented to have a vertically elliptical beam, which fit the vertical orientation of the hologram film plate when illuminated from below.  The entire laser mount from the Hologram Kit was positioned about 14″ from the film plate, and propped up at an upward angle with a small piece of wood so that the laser light was centered on the film plate for exposure.

Now it’s time to make the skeleton hologram!  With the skeleton sitting in position inside the coffin, we turned off the lights, got out a 4″x5″ film plate (LitiHolo Instant Hologram Film), and put it into place sitting on top of the binder clips and leaning back against the top of the coffin.

Here’s an advanced tip:  Let the film plate sit for about 10 minutes before exposing the hologram.  Because the skeleton was a slightly flexible plastic, it is important for the any movements to have time to settle out before the hologram is exposed.  We did one hologram exposure that only waited about 2 minutes, and parts of the skeleton were not visible in the final hologram because of the slight motion of “un-flexing” during the exposure.  10 minutes of settling time worked well for us.

Our exposure time for the full hologram was about 12 minutes.  Because the film develops as it is exposing, you can see the hologram image immediately after the exposure!  Sitting in the dark with the anticipation of viewing your hologram does make the time feel longer, but it was well worth it when we got to see the finished skeleton hologram in the image.

To set up the hologram for final viewing, we removed the real skeleton from the coffin, replaced the film plate, and illuminated the film plate with the laser light again from the same position as the exposure.  Now it looks like there is a ghostly hologram of a skeleton still inside the coffin!  The effect is really impressive in person, and pictures don’t do it full justice.  The mixed media effect of a real coffin with a holographic skeleton also helps reinforce the realism.

For the final touches, with the doorbell and thunder sound effects, we got a standard doorbell push-button swith (we went with non-lighted), and we found a great LED strobe light with thunder sound effects at Halloween City.  We took apart the strobe light unit (remove 4 screws at back), and everything is on one small circuit board.

On the back of the board, we want to use the pins sending power to the one of the LEDs for the lightning flashes to power the laser illuminating the hologram.  Solder 2 wires to the same pins going to one of the LEDs (one pin labeled “-“, and one labeled “+”).  We left all the LEDs connected, but you could cut them off as well.  Use the alligator clips from the Hologram Kit that connect the laser to the battery pack, but now connect the laser to the “-” and “+” wires from the strobe unit.

To test, add the 3 AAA batteries to the strobe unit and push the demo button on the strobe.  The power going to the LEDs is about 3V at its peak, which is perfect for powering the laser unit.  You should get a nice “lightning flash” that operates the laser, along with the thunder sound effect.

The last piece is simply wiring the doorbell to the existing push-button on the strobe unit.  We used an old 2-wire phone cord (old school!) so that we had a good length from the doorbell switch to the strobe unit powering the laser.  Solder the 2 wires to the strobe board where the existing switch is located (labeled “key” on our board), and then screw the leads for the other ends of the wires to the 2 screws on the doorbell switch (polarity does not matter).

Finally, put out some candy, push the doorbell switch, and watch your skeleton hologram glow with a creepy satisfied look on his face (and hopefully yours too)!

The strobe unit also has a straight up strobing effect without the thunder sound that was impressive as well.

We toyed with the idea of hooking up an amplified sound system to really make people jump when they pushed the doorbell and got the thunder effect, but we wanted the focus to be more on the hologram.  Maybe next time!

Parts List:
LitiHolo Hologram Kit
4″x5″ Hologram Upgrade Kit
Michaels – 16″ skeleton – #191518932188
Michaels – paper mache coffin – #191518924770
Lowe’s – doorbell switch – #40199
Halloween City – Thunder Sound Strobe Light – #644137008227
(Also at Party City – Thunder Sound Strobe Light – #644137008227)