[Mehdi’s] Shocking Stun Gun Tutorial

[Mehdi Sadaghdar] never lets little things like fire, shocks, or singed fingers get in the way of his projects.  His latest is a tutorial on making a simple electroshock device. A stun weapon creates a very high voltage, and is used in law enforcement to temporarily disable a person. [Mehdi] stresses repeatedly to not use this on anyone. If you do, he won’t like you anymore. Of course, if you’ve seen any of his previous videos, you know he’ll shock himself and set something on fire before the project is complete.

To create his stunner, [Mehdi] used a car ignition to produce a high voltage. The igniton coil, which is a specialized transformer, allowed him to generate the >10000V output needed for the stunner. The coil has a 60:1 ratio and is powered by a 12V DC supply. Since a coil is a short at DC, the system only creates a high voltage pulse when power is disconnected. However, the pulse was too short to create a satisfying arc. [Mehdi] added a capacitor, creating an LC circuit that oscillates as the charge decays, creating a nicer spark. He then used an RC circuit and a relay to create a simple oscillating switch. For the finishing touch, he created a spark gap on the secondary of the transformer with two nails. In typical [Mehdi] fashion, he nearly fried his digital caliper in the process.

The end result is a nice spark that warms the cockles of [Mehdi’s] fibrillating heart. We commend him for being such a brave masochist in the name of science.  Check out his tutorial after the break!

23 thoughts on “[Mehdi’s] Shocking Stun Gun Tutorial

  1. This reminds me of that kid in school that would do all sorts of horrible things to get the other kids to laugh at him because he was so desperate for attention. I always felt bad when he would eat something gross or pick up the dead squirrel we found etc etc etc. I think that kid grew up to be Mehdi Sadaghdar.

  2. Good old 555 chips and TO-3 transistors, mostly “surplus” grade!
    A few passive components and that ” new old stock”, non internal resistor, automotive ignition coil.
    BZZZZT!!

    Way back in the day, if you ever looked at the breaker points and spark plug gap erosion in our old 2 stroke dirt bikes.
    It usually kept up our semi-healthy X^p respect for the output
    of a non-ballast resitored ignition.
    Sure It cost some point and plug life, but that and gaining a bit carb tuning skills along with synthetic fuel-mix oil (pre-mixed), just flat out cured any plug fowling.
    I felt is was very well worth the increased inspection and shorter service intervals on those old Yamahas.
    You could lug one around in the trees for a while and then hit 4th~5th gear flat out in the pasture.
    With only a bit of fuel puddling in the crankcase to give a briefly rich running condition to tell the story.

      1. I do too. His explanation is very clear and concise. Which is why I’m bookmarking his page. I’m thinking his circuit can also be used to help pump up a Tesla coil, even though he would probably recommend against it.

  3. You soon learn a little respect after a couple of reasonably good shocks. I could almost feel that when the arc hit his finger. It’s always good to have something amusing to brighten your day.

  4. This is not a “stun” device in the sense a “Taser” is.
    The latter device has a specifically calibrated waveform
    delivered to the target (in terms of pulse amplitude,
    timing, etc).

      1. Exactly the point. Taser International spends millions on R&D to
        make sure their products are “safe” for their intended use.

        Otherwise, just use a damn cattle prod – which is pretty much
        a simple ‘zapper’.

        One can Google “taser waveform”, plenty of information out
        there. Including independent labs testing their products.

        I used to carry the M-26, but because it was too bulky and
        visible, decided I’m better off carrying a concealed Glock19.
        And if I have to use it, I want the threat down – hard – not to
        survive and give me legal grief…. LEO’s using M26’s are in
        a different tactical realm (the “continuum of force” thing).

    1. The cheap ones are pretty much a Royer oscillator driving a transformer, charging a hi-voltage cap, driving another really-hi-voltage transformer thru a spark gap, when the cap charges high enough. Cheap Chinese crap that’s profitable at low prices. Really cut to the bone. There’s teardowns on the web.

      Maybe someone’s spent time deducing the ideal voltage and waveform for stunning people with the absolute bare minimum of killing them, but I’ve never seen it mentioned. I’d like to, if there is one. As it is I think the “modern” Taser is to hitting people over the head, what the electric chair is to hanging them. IE “scientific” looking but probably more dangerous.

      Anyone ever take apart a Taser, Inc. weapon? I can’t imagine their police-grade ones are fundamentally different from their consumer model. I bet it’s just the same, unsubtle high voltage.

  5. Same here. Used a “Deadman Switch” on the 12V battery for running my 6 CCFL inverter stack, good thing too.

    There’s a reason the properly made devices use a precision switch, so you have to press and hold it with an exact pressure. Too much and it shuts off until switch released completely, in case user shocks themselves by accident.
    Something to also consider when working on TC’s, etc.

    A good feature to add on anything which can do damage, be it LASER devices or anything using high voltages or spinning blades is to have both a keyswitch and a “push to activate” button. Pull the key during use and it crowbars the PSU, blowing the main fuse but preventing a worse shock.

  6. This is the most entertaining thing I have seen in a long time. I feel his pain, tried to diagnose a miss on an old car with cracked spark plug wires. My hair stood on end. Do not ground yourself to a vehicle with an ignition coil. The newer coil on plugs are way hotter these days than the old style ignition, but they are reasonably safer as you do not supply high voltage over 20-30 inches of wire, you supply it in less than 1 inch.

    1. CSB time. When I was a young lad, I decided to make a mini-monster truck. Took a Datsun pickup with the 2 plugs per cylinder moyor & seriously modded it out. One of the mods was to replace the stock coils with a pair of Accel Super Coils. At 45K+ volts each, they supply some serious spark. So after the 6″ body lift & 6″ suspension lift & 44″ tires, the only way to work on it was to stand on a step ladder. I had a nice shiny aluminum one…
      So, first time starting it up, I climb up on the ladder to adjust the timing, whilst my helper starts it up. I’m leaned over the fender, holding on to the distributor when he starts it. A nice fat arc jumping staight out to my hip. Yelling “T T T T U U U R R R N N N I I I T T T O O O F F F !!!”
      25 years ago & it still smarts just thinking about it…
      /Oh yeah, wooden ladders for the win!

      1. I had a van with the Nissan Z24 motor but I’m pretty sure that was regular single plug per cylinder. This was in Australia though, so perhaps the twin plugs is a US emissions thing?

Leave a Reply to John Cancel reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.