At 07:41 AM 4/3/97 -0800, you wrote:
>At 11:01 AM 3/10/97 -0500, you wrote:

You sure haven't read your mail in a while!

>>I did an altimeter using a PIC and a Motorola absolute pressure sensor.

>Any chance that you'd share the schematic and source for this? (Otherwise,
>why mention that you'd done it...)

Well, why not is because it was a proprietary item for somebody, and I
can't release that source code.  However, it was rather simple:

PIC16C711 pin 17 to Motorola MPXS4100A6U Analog output (I forget which
pin).  Software does the following:

On reset:
        Turn on "Calibrating" LED, turn off "Ready"
        Wait 15 seconds to warm up sensor (required by Mot).
        Turn on "Ready" LED, turn off "Calibrating"
        Call the current reading "0" elevation.
        While the current reading is 0 +/- 2 bits or so
                do nothing!
        Endwhile
        As fast as possible (10mS) store readings into the EEPROM
        until the EEPROM is full (2K or more samples, about 10 secs per K).

The EEPROM is read into a PC, and the readings are plotted out to form a
chart showing altitude vs. time.

>(Who'd like to make an altimeter to fit inside a 1" tube)

Dave

Now you have everything you need.  This is an ideal application of the
PIC12C7x part.

Andy

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Andy Kunz - Montana Design - 409 S 6th St - Phillipsburg, NJ 08865
          Hardware & Software for Industry & R/C Hobbies
        "Go fast, turn right, and keep the wet side down!"
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