So, what do us creative photographer types do when the gauntlet is thrown down and the challenge is issued to build the biggest, baddest diaper cake ever?  Well, we spend loads of time, enlist our engineer friends and create an epic diaper cake masterpiece that is well over 3 feet tall, 2 feet wide, contains close to 250 diapers, lights up and spins.

Okay, so a little back story first.  Our friend Brandi (the pregnant mermaid you see on the topper below) is the baby shower queen.  Over the past few years she has been involved in many of our friends showers (and others for people we do not know as well) and has always been responsible for the diaper cake.  As more and more friends got pregnant and more and more elaborate diaper cakes were created, the talk of what could be done for Brandi’s diaper cake began.  We knew it couldn’t be just your average diaper cake and some ideas were thrown around and the trash talk and hype began.  Rumors of a diaper Eiffel tower surfaced at one point as well as talk about having to rent a truck to transport it to the shower.  As time passed, even before Brandi was pregnant, the legend of what could be, grew.  Finally, the time for baby Robinson had come and the plans for the shower began.  In honor of the couples love for travel and snorkeling, a tropical, ocean theme was settled on and real plans began.

Preliminary designing was pretty quick as we knew what we wanted to do, we just didn’t know if we could do it or not.  So, immediately after the idea of motorized, swimming fish was discussed we went to our good friend and mechanical guru, Brian Amos.  His reaction (after the initial “why would you do that?”) was “sure, it could be done, no problem”.  Words he would later regret I think.  As most projects of this nature go it ended up being much more tricky and touchy than it initially appeared.  Below is a description from Brian of the mechanics of the cake and the work done:

Some Stats:

• 13 custom printed circuit boards
• 2 custom machined drive-wheels
• 2 geared DC motors with constant tension assemblies
• 14 RGB LED’s (pulse-width modulated)
• 1 microcontroller
• 8 AA batteries
• rubber bands and hot glue (no duct tape. . .but there was superglue!)

Electronics Portion:
The lights on the bottom of the tiers are RGB LED’s.  Mixing different portions of the primary colors enables us to produce any color we’d like.  The firmware was borrowed from an LED mood light project originally done in the UK.  It cycles through different, pleasing colors.  Using already-available firmware enabled us to concentrate more on the mechanics and electrical hardware – and less on trying to mix colors that made something pleasing to the eye instead of a nasty brown!  There are several different modes that can be cycled through, from pleasant fading effects between pastel colors to some really obnoxious blinking patterns that mimic police lights.

The electronics hardware includes 1 custom control board and 12 LED carrier boards.  The control board constists of a 3.3V LDO voltage regulator, a PIC12F629 micro controller and some transistors to sink current from the 12 RGB LED’s – 8 on the bottom tier and 4 on the top tier.  There is also circuitry on-board for an audio amplifier, so you could plug in an ipod, etc.  This circuitry was left unpopulated due to IC packaging confusion, a missing speaker, and time-constraints.

We strongly considered adding a second micro-controller, motor control, and changing out the geared DC motors for stepper motors.  This was partly because the steppers may have provided smoother motion and quieter operation, but mainly so we could call it a Dual Core Diaper Cake – that just had a certain ring to it. . . probably the double alliteration. . .

So, ummmm, yeah.  Basically, the fish spin around the top two tiers and it lights up pretty.  All I know is it was a lot of work with a lot of tools I do not have.  We made custom parts in his home made CNC machine, acid etched circuit boards, soldered all kinds of stuff and did a bunch of other things that I don’t remember.

Then, there was the fantastic artwork involved.  All the fish and the characters on the topper were hand drawn by Andrea.  That’s right she drew them all!  We then scanned in her line drawings, added color in Photoshop and printed them out at the sizes needed.  The mechanical part of the cake certainly is amazing but for me, Andrea’s drawings take it over the top.  Note that all the fish are genuine Hawaiian reef fish (in honor of the couple’s favorite vacation/snorkeling spot in Kauai). The pregnant Brandi mermaid and god of the sea Anthony still make me crack up every time I see them.  They really, REALLY look like the couple!  And yes, that is their rat terrier Vinca – as a sea lion of course.

Anyway, that’s the basic story behind the cake and its construction.  Below are a few photos and a video of it in action.  These were all done in about 10 minutes right before loading it up and taking it to the shower, I wish I would have had time to do more.  The top tier wasn’t spinning at 100% at this point but unfortunately this is the only video we got 🙁   The last 2 photos show it with different LEDs shining down but the cool part was seeing it in action in the dark.  There were a bunch of different modes with different colors and flashing patterns (including police mode which was really annoying).

So, what do you think?  Did we go over-the-top enough?  Will this diaper cake ever be beaten?  Was it all a waste of time?  We sure spent a lot of energy on this project and would love to hear your feedback.

Video can be found on YouTube here: Epic motorized light-up diaper cake

And here are the pics: