A word on transformer

[zultekmilennia]

hello, I need some helpful advice here. I'm building a timed shocker and was wondering what kind of transformer that would be suitable to be used other than the one used in the stun-gun circuit?

I need one that will cause the circuit to deliver only 1/10 of the original shock intended from a stun gun. Would 220:1 do, as in 200v to 1v?

Also, I need a way to connect a watch to the stun-gun so that the stun-gun is turned on as the alarm goes off. Of course, the watch need to be able to withstand any back emf that might occur from the stun-gun.

 

[KMoffett]

So, the alarm clock isn't enough to get you up in the morning?

Ken

 

[zultekmilennia]

well, the project is for my english class, we need to present it. Dumb as I was, I proposed something that was little out of my league. And the lecturer even approved it.

And, for some people (like my roommate) have trouble waking up in the morning, so I just kinda blurbed out this thing. As they say, to come up with an invention, think of a problem that need solving.

Anyways, I'm in civil engineering so I don't really know much about electronics. I've been learning a little for my team's railgun project (that's another story) but its still insufficient.

What kind of transformer can I use, and it needs to be small, btw, as I intend to make it into some kind of collar, wearable on the limbs.

 

[Hero999]

Applying a pulse to a mains transformer would do the job.

You could even connect the transformer across the speaker terminals of your radio alarm clock and it will shock you to the beat of the music every morning.

 

[zultekmilennia]

How do I actually apply a pulse to the main transformer?

If I connect the wire intended for the speaker to the shocker, where do I need to connect it, and won't the watch get fried?

I found a transformer from a cellphone charger (Nokia) and it say it has an input of 240Vac/50-60Hz/100mA and an output of 5V-11V/500mA. can I use it?

 

[crutschow]

A note of caution. Currents above a few millamps through the human body can be lethal so be sure to limit the current with a resistor to keep it below that level, say 1000 ohms per volt. It isn't high voltage that's dangerous by itself, it's the high current it can generate. Thus a stun gun generates several thousand volts but is current limited so is not lethal.

In general it takes more than 50V to be felt by the human body so you'll need at least that much if you plan on shocking someone.

 

[zultekmilennia]

So, all I need to do is produce at least 60V-70V from a 9V battery to make this work? So, the transformer I have right now is too high, it seems.

That means I need a 1V to 10V transformer (or something like that), right?

And, again, how do I apply a pulse to the transformer, so it would function like a timer.

 

[Hero999]

In general it takes more than 50V to be felt by the human body so you'll need at least that much if you plan on shocking someone.

50VAC or DC?

I'll assume you're talking about 50VDC.

If you've got moist skin you might feel a tingle but with dry skin you need a much higher voltage to get a shock. I've never tried it myself but I would think you need up to 120VDC, perhaps even more to reliably shock someone.

I was doing some testing the other day with 50VDC and I didn't get shocked even though I acidentally held both the positive and negative rail. I didn't even know the power was on until I short circuited it but nothing blew as the PSU was current limited to 50mA.

 

[SPDCHK]

I was doing some testing the other day with 50VDC and I didn't get shocked

Hero999, you must be thick-skinned . I work with 48VDC for Digital input signals on our DCS system, and I must admit, when that 48VDC "tingles" you, I stand back. I've been shocked once too many in my life to enjoy 48VDC.

Just a note to the original poster. Many times, someone on the forum wants to build a FM radio receiver, and they always get the same reply. "Go buy a cheap radio, strip it down and use those parts and circuit". I'm not saying you must go into radio now
BUT, here in South Africa (and I'm sure if we have it here the rest of the world should too) we have the VERIMARK product sales on TV. One of the gadgets they try to sell you is that machine that contracts the muscles and then gives you a workout. Well, I've opened one of those units and they quite simply have all the needed parts and electronics in there to give you what you need. It's NON lethal, comes in a small casing that can be strapped to the body and the nice sticky pads that can be placed where needed.

I'm sure It will wake me up if the wife puts her machine on me while I was sleeping. That thing can BITE!

 

[Hero999]

Do you often get sweaty fingers?

I've had a tingle of 50VDC before but I did have sweaty fingers, I don't get shocked at all when my skin is dry.

48VDC systems often operate up to 60V (the maximum voltage which is considered to be safe in dry conditions) when the batteries are charging so it's not surprising you get skocked.

The voltage required to shock up varies very widely, under 1VDC can make you feel a tingle on your tongue but the dry skin on the back of your hand can probably take way over 100VDC.

This is the problem witth building a shocking device, what voltage do you choose? You might design it to produce 120V which won't hurt much on dry skin but could be lethal on wet skin. They key is to use a very high open circuit voltage (>1kV) and limit the current to under 5mA for safety reasons.

 

[zultekmilennia]

So, I've gone ahead and started assembling the circuit. Used the transformer from that charger (broke the first one and had to find some other charger) but still lacking a base for the 555 Timer (my friend forgot to buy one).

Anyways, seeing that it can go either way, I'll just go ahead and see how much this baby's gonna give out. But, the transformer's got 2 inputs pin (for the positive and negative) and 4 output pins. Which one would give out the shock?
I'll get one of my group members to test it firsthand.

I still have the problem of setting the timer thing. I bought a cheap wristwatch (digital) and I kinda lost now. The thing's got pins for connecting to the speaker (a thin metal piece) so I'm gonna try disassemble a pushbutton switch and see what can be done...

 

[Hero999]

The transformer doesn't have a positive and negative terminal, as it's designed to run from AC.

A 6V to 240V mains transformer is the best thing to use, it'll generate pulses of 1kV.

The 6V primary goes to the driver transistor and the high voltage on the 240V secondary will shock you.

 

[zultekmilennia]

Yeah, I just labeled for the sake of simplicity. I already inputted the components in, haven't soldered yet. Need to ask roommate (who's an electrical degree student) which direction is the right one for the components.

Of course, that only applies to the diodes, but I have a question about the TIP31 alignment, in the stun gun circuit diagram. It is correct that the C is connected to the transformer instead of the E, right?

And, again, I don't mean like a broken record (which is in fact, a lie) but I still need help on the timer thing.

btw, the transformer got 4 pins for the 240V part, why's that?

 

[Hero999]

What stun gun diagram?

You haven't posted a link or attached anything so there's no way for us to know what you're talking about.

 

[zultekmilennia]

Never mind, its the one in the stun gun project in the project sub-forums.

 

[480threephase]

the watch you plan on using, is it metal or something nonconductive?

if it is metal, you might want to put a resistor into the circuit (yes, i know it was mentioned earlier). perhaps a pot for...adjusting between those who are more difficult or easy to awaken.

if i were to do this, i would use a transformer to convert 120v or 220 volts to about 24v, use a nonconductive watch and incorporate 2 electrodes on opposite sides of the watch.

you could use a basic mechanical timer with buttons to start and stop the timer.

 

[Hero999]

Never mind, its the one in the stun gun project in the project sub-forums.

Please post a link, no one is going to bother rummaging through the forum to find it.

the watch you plan on using, is it metal or something nonconductive?

if it is metal, you might want to put a resistor into the circuit (yes, i know it was mentioned earlier). perhaps a pot for...adjusting between those who are more difficult or easy to awaken.

if i were to do this, i would use a transformer to convert 120v or 220 volts to about 24v, use a nonconductive watch and incorporate 2 electrodes on opposite sides of the watch.

you could use a basic mechanical timer with buttons to start and stop the timer.

Why convert 120V to 24V, a voltage which is unlikely to shock you unless it's AC and you have moist skin?

True both current limiting and an isolation trasfromer are required if you're going to run this off the mains but you wany to boost it to a higher voltage, not a lower voltage.

 

[480threephase]

i wasnt talking about rectifying it, just transforming it...besides, if we really wanna shock, why not just use a capacitor??? <---evil smile

 

[bloke_man]

Of course, that only applies to the diodes, but I have a question about the TIP31 alignment, in the stun gun circuit diagram.

btw, the transformer got 4 pins for the 240V part, why's that?

Oh-boy! we are getting into dangerous territory now, stun guns are very nasty pieces of work, they are a hybrid of cattle fences and are designed to drop large animals with thick hides.

Although most law agencies use them, some have resulted in heart attack!

Be careful!

 

[killivolt]

Danger Will Robinson DANGER !

I agree ya don't need to drop-'em just get their attention.