This circuit was designed by Matthias Stehr (http://home.t-online.de/home/Matthias.Stehr/projecte.htm). The design uses a PIC16F877 to measure the output of a temperature sensor and an absolute pressure transducer to measure altitude. Specifically, the design provides the following features:

	displays the current air-pressure
	displays the current temperature
	calibration
	saving and displaying the reference pressure
	calculating and displaying of the relative altitude (resolution 7m)
	saving of the altitude data in a 2k EE-Prom in a interval from 1s-60s (result in a recording time from 17min - max. 17h)
	can be powered by a  9V battery (about 24h) or a 12V DC power supply unit
	operation with 3 keys and  LCD menu
	saved data can be transferred to a PC with illustration and transfer handled by a C++ program
	data can be saved in a simple text file
	PIC Source in C (PCM PIC C Compiler by CCS)
	illustration program source in Borland Builder 4.0 C++

Click the above thumbnail to view the schematic

Click the above to see a sample output from the Illustration Program

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