plot thermometer / clock for 3D printers

Update #5: Description of the calibration process -> Instructions
Update #4: Minor bug fix in the Calibration routine -> v1_1b
Update #3: Improved servo arm attachment. See Instructions
Update #2: Additional version of the servo arms. See Instructions
Update #1: Videos of the plot thermometer/clock: http://youtu.be/0nTKUaYZzgA and http://youtu.be/XSc-_maon80 (please see further update info under instructions)
This plot thermometer and plot clock is based on http://www.thingiverse.com/thing:248009 and http://www.thingiverse.com/thing:255608
Initially only with the intention to replace the screws with printed hinges I made several improvements:
Hardware:

Printed hinges
Fully cover of the electronics
Covered servos
Thermal measurement
Integrated switch and power jack
Hooks for wall mounting
I2C connector for further enhancements like motion sensor etc.
mechanical stability
FDTI programming port for the arduino
Magnetic drawing board holder
Software:
Inline calibration & setup (use x when connected to a 9600 serial terminal)
EEPROM storage of the calibration values
temperature measurement capability based on a DS18B20
possibility to choose between time and temperature display
Display flip capability (for wall mount)
switch for multiple functions (temperature or time / plot on or off)