Detect Power Failure

[BobP]

Hi,

I would detect the 5v from the PC's USB socket. When 5v disappears check again for about 400mS to allow for spikes then send your serial data to the other PC.

Bob

[koossa]

Great!
I would try it!

[koossa]

Will I use a Transistor to detect power on the USB Port?

[BobP]

Hi,

If you are going to use a seperate 5v supply say the 5v from the other PC I would strongly recommend using an optocoupler to monitor the 5v.

Bob

[koossa]

Thank you!!

[mister_e]

What happen to the USB power rail if someone reboot the computer or shut it down for a short period of time (if at all possible or allowed)?

In this case a simple wall-wart transformer would do the job too.

[koossa]

Mister_e

Would I still use the optocoupler if I rather want to use a transformer?

Thank you

Koossa