With a $40 pay-as-you-go cell phone, stun gun, and some basic electronic components, you can teach bike thieves a lesson and, hopefully, foster a small social change through individual action:)
Shameless self-promotion: I've got this and my other stuff for sale here
Updated: here's me demoing this at Dorkbot Austin last month. And yes, I shock myself:)
Here's the original video of me explaining details on building this:
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Signing UpStep 1Ingredients
For a basic system that shocks and tracks, here's what you'll need:
-stun gun; I used the basic, ~50,000 volt one I found at a local sporting goods store. ~$20. You could also mod an instant camera or build one from scratch...
-Phone capable of talking to some tracking system. I went with mologogo, but feel free to play around with others. For the boost mobile motorola i425t, I paid ~$40. Unlimited internet service is like 35 cents a day. I haven't tried, but I've heard reports of being able to use mologogo without buying the net service...
-a diode to connect in paralel with the stun gun, because we're obviously concerned about safety...
-assorted thin-gauge interconnecting wires and non conductive electrical tapes
-circuit protobyping board
-a basic npn transistor, with datasheet. i used the 2n5088.
-a resistor sized based on your transistor. i used a 1.5-ohm one
To choose the right transistor and resistor, read this guide and look at these circuits. If you're using this same design as I did, the load you're trying to control is the 9v battery connection to the stun gun at 9volts 2.8 amps. If you go off the vibrating motor, you're controlling this via something like ~5volts .5 amps...
Useful tools were:
-screwdriver for the weird screws in the back of the cell phone. it was like ultra-tiny torx or something; your best bet is to get the phone, try your existing collection of weird screwdrivers, and get a specific new one if you need to
-utility blade
-multimeter (with ammeter)
-wire stripper
-soldering iron, solder
-'helping hands' alligator clip + magnifying glass thing
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@most everyone else - note the why would I care if someone got injured after stealing something of mine? If just one person did actually die from stealing a bike, word would spread quickly on the street and in the media, and there would be an instant reduction in bike thefts. I fail to see any problems with this. There are or were places where caught theives would lose fingers or a whole hand as punishment. If this was the case in these USA now, we would have next to no theft.
@liseman - Good idea on self-protection!
Finally, does a mountain climber stop climbing mountains because someone else has fallen to his or her death? No, the climber assumes that the person who died was either foolish, unprepared or unlucky. They might even feel additional an thrill while climbing mountains because someone else has died doing the same thing.
Finally, was the mountain public domain or did the climber get permission from the land-owner? If neither, then was the owner still at fault for the death of the climber? No. And if that climber is carrying my bike off up my mountain then I think I may cut off his rope and let him ride my bike down the cliff, or just shoot. once for a warning, twice for ignoring it.
The reason why we have an appeals process is because people get convicted of crimes they didn't commit. It's supposed to reassure those who were just in the wrong place at the wrong time that the justice system is indeed about justice - not meting out punishment to whomever is on hand. Self-protection is legal - provided - the action is commensurate with the intended crime. If you (to use the case at hand) electrocute someone for stealing your bike (or push them off a cliff, as you seem to be indicating in your post), you may very well find yourself staring a life sentence in the face.
In other words, the newspaper headline "Crazy Dude Electrocutes Would-be Thief, Faces Murder Charge" will probably not serve as the deterrent to crime you feel it should, much as the Columbine massacre didn't reduce the bullying of skinny, mentally-unstable fans of Marilyn Manson.
That said, we were talking about killing people for stealing a Huffy.
As for those "places" where caught thieves lose finger, the US isn't one of those places. So, if you live in one of those places then you're good. If you live in the US - criminally and civilly liable.
Also, if someone who isn't even remotely connected with the theft is injured by you zapping the thief, as in the thief goes down in traffic precipitating a car crash that kills/injures someone, they you're on the hook for that as well.
Cheers.
Tally ho
"939.49 Defense of property and protection against retail theft. (1) A person is privileged to threaten or intentionally use force against another for the purpose of preventing or terminating what the person reasonably believes to be an unlawful interference with the person's property. Only such degree of force or threat thereof may intentionally be used as the actor reasonably believes is necessary to prevent or terminate the interference. It is not reasonable to intentionally use force intended or likely to cause death or great bodily harm for the sole purpose of defense of one's property."
So, assuming the thief touches your bike, gets shocked, then walks away, you're fine. But what if, in the process of riding your bike, said thief takes off his gloves, gets shocked, and falls into traffic. Do you want to be a killer?
And what about a curious child? What if your bike falls and some good-doer wants to put it back up?
In shorthand, if your bike does NOT have any warning about the existence of a potentially fatal security system, it might face the scrutiny of law.
However...
If one has been warned of a security system then chooses to disregard it, gets shocked and run over by a car, it's their own fault. It's the same scenario as if you were to touch an electric fence, get knocked back, and drown in a puddle: it is YOUR FAULT for touching the fence; the rest is a consequence of a really bad choice.
it works by flipping the polarity of the battery and built in ingintion coil will work wonderfully off of drill batteries or anney other source greater than 6 volts up to 16
30V is the maximum voltage that can be applied under worst case conditions (sweating, standing knee deep in salt water) and not reach 30mA. This is the standard for hospital grade electrical equipment (that's what that green dot on some plugs and electrical outputs signifies).
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The stun gun is likely not lethal in its original configuration (electrodes less than 1 inch (2.5cm) apart) so there's little chance of driving a significant current through more than a few inches of skin, but increase the spacing and all bets are off.
F.Y.I.
Amps = ampere = current
Volt = voltage
Ohm = resistance
Amp = Volt / Ohm
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It’s hot, but it's a dry heat.......
Watts ( W, a unit of power) = V * A (Volt * Amp)
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AC terms (alternating current):
For resistive loads (incandescent lamp or heater), the same equation still works.
With reactive loads (motors), things are more complicated as the voltage and current are not in phase - they do not measure zero at the same time. Current usually lags behind the voltage (assumes voltage and current are both sine waves). Additional terms needed for this discussion include frequency, phase angle, true power, apparent power, reactive power, power factor, and complex impedance.
With harmonic loads (fluorescent lamps, most electronics, and lamp dimmers), current is either in phase with voltage, or is zero (current is not a sine wave, may be a pulse during each half cycle). Additional terms for this discussion include frequency, harmonic distortion, and crest factor.
More than you wanted to know?
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For purposes of the stun gun, we can assume a resistive load across the electrodes.