[TriEmbed] Coffee roaster

[Brian]

> The article links to this as a temperature sensor: 
> http://www.produktinfo.conrad.com/datenblaetter/175000-199999/182907-da-01-en-IC_ZTK_33.pdf
> That does not look correct... am I missing something?

You're not missing anything!  That particular component is a 
temperature-compensated voltage stabilizer, which means its behavior 
varies in a known way with respect to ambient temperature.  Note that 
ALL conductive materials have thermal coefficients; things like 
thermistors just use materials with particularly high coefficients to 
create a bigger working signal.  While that part only superficially 
looks like a diode, it's also true that diodes find common use as 
temperature sensors embedded in silicon (e.g. your computer's CPU's core 
temperature sensor is probably a diode).

As to why the designer chose that particular part, I can't guess!  I can 
only imagine that its operating temperature was in the right range for 
the application (I suppose the coffee-roasting temperature doesn't 
exceed 150 C?) and provided a useful signal when connected as described.

Hope this is informative!
Cheers,
-Brian