Reading currents and controlling voltages in c++

Mr_Grieves

Hi all -- I'm writing a controller for an interferometer and I need to be able to control the voltage across a terminal and read the current from a photodiode in c++. What would be a good, reasonably priced peripheral that would accomplish this, preferably with linux support?

Better yet, is it possible to perform this using the 1/8'' speaker output with any real precision?

Thanks,
Dave

Mr_Grieves

As a note: I'm very new to writing interfaces between programs and peripherals. If I'm going about this the wrong way, let me know. Please, no suggestions to using LabVIEW though :)

mgb_phys

The microphone input is generally 8bits and pretty fast 20-40khz, you are probably going to need to build more electronics to interface to it - but it will be cheaper than using custom hardware http://www.techlib.com/Karen/misc.htm#Mic Input Telemetry

In the Uk these people are great http://www.picotech.com/, otherwiseyou cna probably find similair stuff locally. Look for devices aimed at education (http://www.heathkit.com/) or hobbies rather than the industrial control ones.

Mr_Grieves

Cool. Is there a set of linux libraries that will let me control/record the mic signal in c++ that anyone can recommend?

Dave