Analogue input

Hello all,

I have the need to monitor analogue signals coming from gas flow meters in CNCLinux and have searched on how to do this but in vain. Is there a HAL component that can do this? I was hoping to use the microphone input as an ADC and the headphone outputs as DAC because I only need two signals.
Has anyone done this? My parallel port is completely full and I have a mini-ITX system so not a lot of expansion space.

Thanks

davidmp

Interesting idea. Do you know of any projects on the web doing this hopefully ope source ones with code samples?

perhaps an arduino connected via usb

andypugh wrote:

andypugh wrote:

There might be some clues here:
wiki.osdev.org/Sound

This looks more relevant:
tldp.org/LDP/lpg/node84.html
And seems to indicate that ioctl() is the way to get low-level access

I think sound cards are AC coupled, so won't work for slowly-changing inputs.
ioctl() only permits a privileged program to gain access to I/O registers.
The wav interface to the sound card moves blocks of raw samples in and
out, not a single sample a a time.

Jon

I am using an arduino to measure spindle temp and offset z automagically..

I followed these examples..

emergent.unpythonic.net/01198594294

works very well so far

electronicsam.com/images/KandT/testing/S...on%20HM2-Servo-1.png

sam

DIY oscilloscope using a sound card.
It seems 0 -.05 volts would be safe but others have used up to aprox 5 volts (but an AC current not DC)
They recommend a voltage divider to keep voltage to a reasonable number.
If you had an old sound card hanging around might be interesting project ....

www.micahcarrick.com/pc-sound-card-oscilloscope-linux.html
www.yann.com/en/diy-turn-your-gnulinux-c...cope-29/09/2010.html

Thank you every body for your replies. I didn't know the audio inputs were AC coupled. This will make it not work for my purposes so...
Does anybody have any ideas for a small DAQ that can be read through the RS232 or Ethernet ports and display values on AXIS?

Thanks