What do you want for breakfast? How about a nice bowl of Crummy Crunchies?
… as in the infamous fake cereal from Haredevil Hare (the Definitive Bugs Bunny cartoon)
The CrunchBox is a talking cereal box. It’s self powered, with three shake flashlight generators embedded in a foam block charging a 3.6v Ni-MH battery. A bridge rectifier converts the alternating current induced by passing the magnet through the coil (left side of the diagram below), to direct current to charge the battery.
This powers the Radioshack voice recorder/player (catalog number 276-1323) which is rated 50mA @ 9V, but runs nicely on 2.2V, although the pitch rises as the voltage drops. Below 2V, the player doesn’t function at all. Note: you have to carefully solder to the switch on the circuit board: the play button is integrated on the board. Make sure not to bridge the terminals! I covered the wires with some hot glue to make sure the leads didn’t break off.
A microswitch glued to the box side closes when the top is opened, triggering playback.
To add the coup de grace, some real cereal is in a shortened bag in the top, covering up the electronics, and a witty graphics package covers the (by comparison) pedestrian Weetabix box.
NB: don’t take this on the subway or ship it, as it does look rather suspicious. (see above)