Very nice description / solution!
And one biiig opportunity: no software changes, because you can use the actual used ones (Pin 3 & 4).
USB: thanks for reasearch... I've found some info too.
The idea of USB is easy installation and hot-plug of devices. Therefore there are no ports but the devices have an ID. So the driver does all the redirectment (using COM or LTP you had to define the port number).
BUT the USB Lamp has no ID.
So I must have functions to control the USB Hub and Sub-Hubs to find out where the lamp is plugged.
And that is nearly impossible for me.
Conclusion:
There are 2 easy ways to make an USB LED flashing:
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[*] way Do that relais thingy. It's easy to make and you do not have to change wires at the USB LED.
[*] way Use an USB2COM Adapter. But that's a little bit expensive for sch an project... ~20€
[/list]
And the winner is......... RELAIS
Just a few additions... You do not need a fully configurated RS232 Cable...
If you have on unused - good, use this. But don't buy one if you don't have one.
Just connect pin 3 & 4 from the serial port with the Relais input (Relais should have power range from 1 to approx 15V, because the power raises if alot Amperes used...read so, don't know if it's true for all of you, because the power and available Amps are depending on the mainboard you have).
Everything should work just fine then. (Relais has to be fast enough of course).
Very nice idea huuf. I had the same but tried to make it by software... But that's rather impossible.
