On 23/05/2011 21:18, Yigit Turgut wrote:
>> >
>> >
>> >
>> >
>> >       ___[Constant current source]_____[ PIC AN0
>> >      |                               |
>> >      +                               |
>> >  battery                            |
>> >  battery                            /
>> >  battery                            \ unknown Resistor
>> >      -                               /
>> >      |                               \
>> >      |_______________________________|_[PIC GROUND
>> >
>> >
>> >
>> >  You get the same reading as you have no current loop. Since the PIC i=
s
>> >  high impedance you just see supply
> Nice approach, thanks for the hand also the illustration.
>

Though possibly Olin can't view it as he uses an old version of Outlook.=20
Or maybe he can as I only put spaces. No tabs :)

I have plenty of web server space, but sometimes a quick ASCII art is=20
less effort than Eagle + Upload.

Reading Analogue inputs on Microcontrollers since 1983. The main=20
difference snow is one chip replaces entire Eurocard and no tedious=20
EPROM erasing and programming. I so like my PicKit2 and ICSP connectors=20
on little scraps of stripboard..

Scroll 1/2 way down page: http://www.techtir.ie/node/1003699

See the 5 ICSP holes at bottom right corner just in front of where the=20
LEDs Daughter board plugs in?
White wire across top of board is input 8V to 16V divided by two=20
resistors connecting to AN0 to read supply voltage.

I used up an old 16F876, next version will have 12 digit VFD so more=20
that one thing (say RF level and Frequency) can be displayed at once.=20
Likely 18F4550 or 18F2550 with USB and RS232 for logging / remote.

Today I figured out how to drive the Futaba 7 segment 12 digit +=20
annunciator VFD. I manually got nice glowy segments. I can use either=20
LT1084 or a LM393 + FET (VN2222, 2N7002, BS170 etc) to generate either=20
+24 or -20V approx to run the VFD. The LM393 works very well.



--=20
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