SpongeBob Boombox Mark II

SpongeBob Boombox Mark II

I’ve been very busy for the past few weeks on a project.  This Christmas we will be sharing with our 1 1/2 year old grandson and I wanted to mark the occasion with a special present.  I managed to get it built with a couple of days to spare, despite some setbacks.  Here it is:


Yes, it looks rather hideous but what does it do?  Well, when you first turn it on, nothing very much.  The nose shines green for a while, to give you time to get clear.  Then it simply shuts down and waits.  But when someone approaches with 75 cm, the nose shines green once more, the front lights up, and a small voice says “Danny, is that you?  I want to play!  Come and play with me Danny! Etc …..”  For about 10 seconds.  During this time the nose turns red and green before settling down to  blue.  Now it’s ready to play.

A large knob on the side adjusts the brightness of the nose:



The round red button sounds a (fairly quiet) buzzer.  That is, unless the square red button on the other side has been pressed


in which case the round button also causes the nose to glow red.  The black button does nothing, unless the small switch at the back is turned on.  Then it starts up a small motor which spins a spiral disk, seen through a small window on the top.  That’s about the whole repertoire.  Oh, and the holes and labels for volume controls etc have now been covered by stickers.

Inspiration came from something rather different:  a Halloween Jack-O-Lantern described here.  When someone approached, this glowed a sinister red, wolves began to howl loudly and lightning flashed.  That if someone was a 1-year old, the wolf howls would no doubt be followed by other loud howls.  It obviously needed to be a little less frightening.

Then I saw another project called “How to build a smart baby“.  That seemed ideal.  The parts list included a 3D printer (!) which as yet I do not have.  I needed a box.  I found the perfect solution at our local recycling centre: a CD / radio called a ‘SpongeBob Boombox’, going for $5 because not much worked any longer.  So out came the internals and off went an order to Deal Extreme for:

Total cost?  Less than $25!  Well, for those three. Plus $10 for an amplifier, and a few thousand dollars worth of labour.

The heart is the Arduino, which you might be able to see buried in the mess of wiring:


The voice recorder was very quiet, so I added an amplifier, a little 0.5W from Jaycar:


The ultrasonic rangefinder which I use as a proximity sensor fitted in very neatly:


The front had holes for pushbuttons to run the CD player, which were ideal for mounting LEDs.

I just love the open source philosophy behind the Arduino movement.  It’s enabled me to learn a whole lot about electronics and programming, really important at my age for my mind to be stretched.  So in that spirit, here are the files for the circuit and software:

This is being written prior to Christmas.  I’ll try to get a photograph later of it in action.  So watch this space.

30 Dec:

Well, it was a success.  Even survived a few bumps so far.  Be interesting to see how long it keeps going.





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