Hi Raymond,

you should be aware of another aspects of USB - there is maximum length of
the cable - only 5m. Perhaps you want to allow your experimental objects a
bit more freedom. Besides the USB protocol is quite complex, probably not
worth the hassle for a one of (or a few of) project.

If you still go for USB, perhaps something like body -> analog -> a/d ->
pic -> SPI isolation -> USBN9602(3) -> PC should work well. The advantage
of SPI interface is that its signals are all unidirectional. You could also
isolate the a/d from the PIC.

Josef

>Dear forum,
>I'd like to transmit physiological information from a human body (ECG) to a
>PC.
>USB is a possible solution for the connection to the PC, but I need a 4KV
>isolation between the human body and the PC.
>Is it stupid to think to isolate the USB bus?
>Did someone implement an USB bus isolation?
>Thanks for your help, and best regards,
>Raymond Ranwez,
>Belgium


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