USB reading in c++

[kaspar_silas]

I was hoping to use a serial to USB lead to make a simple data acquisition system.

I am looking to sample a 0-3v signal at say 4hz writing to an ascii file.

Has anyone any idea how to in c++ actually sample a signal from a USB.

Any help is greatly appreciated

[Zugzwang]

Note that those converters will only function properly if the input to them follows the protocol. And "0-3v" doesn't seem to be of that type. You will almost surely need additional electronics on the hardware side (like an OP-amp for amplifying data and a some device sending TxD signals at 4hz). And this will only capture digital data. You can however buy off-the-shelf hardware for analog sampling.

Apart from that you can just install the usb-serial driver correctly and read from that port like from a file. See here: http://www.linux-usb.org/USB-guide/x356.html

[kaspar_silas]

I did think I would have to condition the signal somehow but I wasn't expecting quite that much.

Op-amps, ADCs and so on will probably cost me more than a cheap USB DAQ box.

O well thanks anyway