We got a cat toy a long, long while back. If you bonked it hard enough it would start blinking for a while. In the long time the batteries faded and it blinked less and less.

By the way, we moved with this non-blinking cat toy.

This is the “Flash Ball.”

Yesterday I decided to pry it open. WIth a bit of careful (and not so careful) knifework and prying with screwdrivers I was able to get the two halves apart.

I got to the batteries in the other half. They are standard 1.5V nominal button batteries.

They are supposed to be 1.5V at least. The intervening nearly decade of time passing has diminished their potential a bit…

A scosh more than 1/2 of the voltage remains… that being said this is far beyond what the datasheets say is “drained.”

Luckily, I had ordered a flat of just the same batteries off ebay a month or two ago.

These are a bit better.  :-)

The circuit itself is very simple though. It’s just a spring coiled around a pin to sense shock:

The rest of it is just an epoxy-covered chip and a few leds.

From looking at the other side without the solder mask it’s easier to see how the traces are laid down:

It turns out the chip has a total of five connections:

  • Ground
  • Vcc – +3 V
  • Top led to ground through the chip
  • Bottom led to ground through another lead to the chip
  • A connection to ground the spring to the center post

I think reverse engineering (or re-engineering at least) this to components will be fun!  :-)

In the end, the ball blinks!