Embedding USB sticks

The Compaq T1010 used in my Blitzortung setup has a 1GB USB stick as the hard disk. OK it's not a new idea but it does have one drawback. How do you know if the stick is being accessed when it's inside of the machine?

To start with I soldered an additional LED across the one on the stick (take the stick out the case first). The first 1 worked for months with this arrangement but eventually something broke and the LED stopped working.

So after a bit of thought (and some inspiration from messing with a MIDI Thru box) I came up with the following circuit:

The PNP transistor can be any thing suitable e.g. BC212 for a single LED or a BD680 for loads of LEDs. R3 is the appropriate current limiting resistor for your choice of LED, 560R in my case. R1 acts as a current limiting resistor for both the 6N137 input and the USB stick's LED driver.
The circuit works fine with the stick's own LED in circuit or when it is removed, I left it in.

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