Instructables
Picture of USB Dead Drop Tester
I was very intrigued by the Dead Drops project (http://www.deaddrops.com), and as I was reading some of the comments, I came across one that said "I can't wait until someone hooks a car battery up to one of these. Then I'll be screwed". Well, I would be screwed too, so I decided to make a simple USB device to test for the presence of any current. The device has different volumes and tones, and the higher the volume and pitch, the more voltage. It has a max of 20V, which should be sufficient. Still, it would be better to pop one of these on a USB drive wired into an outlet as oppose to frying your nice little netbook.

To begin, gather the following supplies:

1 USB extender cable (Staples or RadioShack)

1 Piezoelectric Buzzer (Found at RadioShack)
=OR=
1 LED of choice, I wouldn't use them because they can't take as much voltage, unless you get some with very good resistors, which I have plenty of, but may be harder to find. In the following steps, just substitute an LED in for the buzzer, and it will all make sense.

Some solder (Your garage, or RadioShack)
A soldering iron (Your garage, or RadioShack)
Roll of electrical tape (Get 3M, high quality and well made. Your garage, or a hardware store)
5 minutes (Find some somewhere)


 
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slangel1 year ago
What happens, if all 4 contacts are shortend - without any power source? will this fry the USB Port or maybe the whole device? I don't want to try that at home.... :D
DIY Dave3 years ago
Good idea, but couldn't somebody connect high voltage to the data wires? Your tester would not detect it but the voltage would still screw up your computer.
builderofcoolthings (author)  DIY Dave3 years ago
(removed by author or community request)
What I think would be the best solution is to take a usb extension cable and solder in fuses in-line on all 4 of the wires. Then if there were high voltage connected, it would blow the fuses and not your computer.
builderofcoolthings (author)  DIY Dave2 years ago
That would be the best option, Dave. Have some fuses in there rated at a very very low voltage, so if you plug into it and it's putting out power, it'll fry it, and then you can take a hammer and smash that dead drop, or investigate and remove it.
I was thinking about putting voltage through different wires and the danger that could pose...

Personally, I would have gone the bulkier and more expensive option and put a buzzer on the red/black wires and the green/white wires. Depending on if the buzzer has a polarity then I'd solder the red to black and black to red, then take another buzzer and solder black to black and red to red.

I'm tired and I'm not quite sure what I'm talking about soooooo...
This might not make any sense.
At all.
jamy0152 years ago
Just take a USB hub with you and plug the thing into the dead drop. If smoke comes off of it, that's a bad thing.
Culturespy3 years ago
There's a USB dead drop right outside Instructables HQ!

http://www.instructables.com/id/USB-Dead-Drops/

Come visit!
Is it wired to a car battery?
I guess you'll have to build a dead drop tester and come find out!
lemonie3 years ago

Have you found a dead-drop?

L
builderofcoolthings (author)  lemonie3 years ago
Nope, not yet. I am in the process of creating a few though.
Kiteman3 years ago
Have you checked it works on a "live" USB plug?
builderofcoolthings (author)  Kiteman3 years ago
Yes, I have hooked up the other end of the cable to a power supply, and tried a variety of voltages. It works great!
cool, guess you could also test voltage drop-off on your usb cables as well.