USB Dead Drop Tester

Howdy all! 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)

Step 1 Cut and Strip the Cable

Start by cutting off the male end (end you plug into your computer), and put it aside for use on another instructable or project.

Move your cutting implement down to the other end (female), and measure 1.5 inches from the base of the USB plug, and make a cut.

Then, measure approx .5 inches from the end of the cable, and cut/strip off the insulation, until you can see the red, black, green, and white wires. Cut off all excess rubbish on the cable.

Next, CUT OFF the green and white wires. Those are useless, as they are meant for data, not for power.

Now that those have been removed, strip the red and black wires, so they are exposed.

Take the buzzer, and cut the wires to a desired length, then strip them as well.

Comments

[jamy015]

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.

[Culturespy]

There's a USB dead drop right outside Instructables HQ!

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

Come visit!

[jakebaldwin]

Is it wired to a car battery?

[Culturespy]

I guess you'll have to build a dead drop tester and come find out!

[DIY Dave]

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]

Good point. It would screw it up, but if someone is stupid enough to hook a battery to it, I would assume they'd do red to red, black to black. But it isn't best to assume things. Hmm, perhaps a small Arduino circuit would be the finishing touch? A high capacity resistor and such, so while it's resisting the voltage, the circuit could analyze it? Hmm, or make a compact voltmeter and have the leads hooked up to the female end of the USB cable, to get a good readout. That might work better. Then again, what if they wired it backwards? It might not work then, or you would have to do 24 combos of wire arrangement (4!) in order to get something. Ehh, that might get complex. Good point. Let's PM back and forth, and see if anything can be developed to prevent this.

[DIY Dave]

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.

[jakebaldwin]

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.

[lemonie]

Have you found a dead-drop?

L

[builderofcoolthings]

Nope, not yet. I am in the process of creating a few though.

[Kiteman]

Have you checked it works on a "live" USB plug?

[builderofcoolthings]

Yes, I have hooked up the other end of the cable to a power supply, and tried a variety of voltages. It works great!

[technosasquatch]

cool, guess you could also test voltage drop-off on your usb cables as well.