Talking pub signs...

[Gordonjcp]

... play back samples of speech when a shadow falls across them.  The covers are held on by security hex screws.  The tamperproof covers reveal a stack of AAA batteries, a wee speaker and a board about the size of an Arduino with a Winbond W58300 sound chip, a TDA7052 audio amp and a socketed 8-pin EEROM chip.

Allegedly.

'Nuff said.

[Circuitbenders]

'tamperproof' you say?