Shake stick - Persistence of vision wand kit

Flash Stick AT89S52 DIY Kit Magic Wand

Ebay listing: Shake Stick Suite Flash Stick AT89S52 DIY Kit Magic Wand New

So when I saw this kit for £2.51 I was intrigued.  I imagined that due to the layout of the LEDs when you shook the stick back and forth that it would show some form of pattern or words.  I ordered one and when it arrived the package didn’t contain (and never had done) the circuit board.  A simple complaint via eBay resulted in a second much bigger package arriving which then had the board in it as well as all the parts again - so I got some spares as well.

It was quite an interesting build which took 35 minutes and you can watch that time-lapsed to a minute:

The PCB was well made and the legend very clear - There was a socket for the processor - and a couple of capacitors, the crystal for timing and a resistor live under there.  But I nearly killed the chip trying to insert it into the socket - you can just about see that in the video - about 10 minutes were spent trying to get it inserted without bending the pins.

The heart of the Stick is an AT89S52:

As you might have seen at the end of the video - shaking it reveals the word 'LOVE'..  Wasn’t expecting that.  

At the end of the stick is the shake sensor seen below:

This looks like its a spring with a wire in it - which will sense vibration by the spring touching the wire when it wobbles.  This must then trigger the chip to start its word sequence.  I note that there is another space on the board above for another component which I suspect may be a mercury switch - but people are (rightly so) scared of mercury now so it may be that they made the board with these two options.

Just above its power switch, the board also has a tact button and when you press it it changes what appears on the display - so as well as the word LOVE, you get a love heart, some smiley art and then some words in Chinese (which cycle through three sets of words..) I am disturbed as to what this may say!

There is also what looks like an AVR socket and another (unpopulated) set of pinouts - I’m hoping I can use this to clone the software on the chip.  

Ultimately I’d like to get hold of the source code for this - but I doubt if I can reverse engineer the chip code.  If this is a far east copy of a well known board and you can point me in the right direction to the source code please leave a Disqus comment below.

14-Mar-2015 Add comment