This small project is more about design rather than the (relatively simple) electronics.

Order from Elektor
PCB, bare, 120481-1
PIC18F14K50-I/P, programmed, 120629-41

This seems like an ordinary bookcase, but on closer inspection one book is the odd one out. It's a "book" with a built-in temperature display.

The fake book contains an integrated thermo-/hydrometer. The "book" itself is made from perspex with a cover glued on.

Hidden between the real books it doesn't stand out too much, but I have found out that once people have discovered it they can't take their eyes off it!

If people are interested I will gladly write a description of the electronics (PIC with Sensirion sensor).

Order from Elektor
PCB, bare, 120481-1
PIC18F14K50-I/P, programmed, 120629-41