"Chris Hornberger" wrote in message
...
I'm looking to build a simple analog to digital circuit as a pet project
thing, to help me get back in to electronics. I tinkered quite a bit as a
kid, but I'm rusty. Very rusty.

Here's what I'm looking to do... measure the voltage/resistance on a
sensor
as it approaches ground, then turn that value into some digitally
transmitted value.

The example would be, say, the temperature sensor on the average
automotive
engine, and pump that value at an RS232 line. I'm a programmer and can
handle the software side of things on the computer or data acquisition
device (probably in Java). I guess I'm just looking for a little guidance
on
the converter/hardware side.

Any place in particular I should look, and/or could someone lend a hand?

Thanks.

--
____________
chornbe - yep, that's me
http://www.chornbe.com
http://www.sanspointe.com
chris at chornbe dot com

GL1100 rider
programmer
woodworker
all around nice guy!



If I were doing it I would use a PIC chip as Paul suggested. However there
are other ways to do it if you do not want to go through the learning curve
to program a PIC chip.

1- Use an Analog to Digital IC, make a resistor divider to scale the range
of the Temp Sensor to the input of the DAC. Take the Digital output to a
MAX232 IC (RS232 converter). The rest is in your programming.

2- Use a Voltage to Frequency converter IC (check Analog devices, National
Semiconductors to name a few). Input the IC with the resistive divider as
above, and output the digital again to the MAX232 IC.

3- www.dataq.com has a neat package for $25 that inputs several Analog
channels and outputs that data in a graph on your computer! I bought one
awhile ago, it does the job.