April 11

Taser Proof Clothing…

Just read a report about the rancher in Nevada whose son was tasered by the Feds (read about it here ) for being on their own land and on land that the state of Nevada has allowed ranchers to use for grazing for years.  The Feds have come “swooping” in to protect some stupid turtle.  Another Fed grab of lands that should belong to the people.

Now, to be sure, I do not think all government personnel are thugs… however the less local they are, the more thuggish they seem to act.  You local cop or even your state police are probably people you know, and are at least people who live where you live.  But in this case we are talking Total Thuggery and Total Unconstitutional action.  Your essential Jack-Booted Federal Agent with a superiority complex.

This, of course, is not the first time Fed thugs have used tasers on innocent people – now don’t get me wrong, there are plenty of criminals who need to be tasered.  It would be nice if the Feds would spend their time and resources going after real crooks, for example the Mexican cartels that are crossing our borders – but instead they keep going after the people of this country.  But I digress…

It is time we put a stop to innocent tasing.  To that end lets explore Tasers and Taser-Proof clothing and how to make them both yourself.

This post will look at some interesting projects others have done – I’m not saying one way or another if I have done it. 🙂

The basic principles are simple – just short out the taser by making an electrical pathway that is much more conductive than the human body.  Tasers work on the principle of injecting a high voltage square-wave Alternating Current (AC) into the body by 2 contacts  so as to disrupt the central nervous system.  Shorting those terminals out removes the offending voltage from the body, while also possibly destroying the taser device (if it is cheaply made).

So first we need to know what we are dealing with… what is a Taser?

Donut_Taserjpg

I said, hand over that doughnut!!!

Here are a few circuit diagrams so you can make one, take one apart, and basically understand what they are doing.

stun-gun-schematic stungun Stun-Gun-3a stun_gun1 dazer stun-gun-schematic-555

And here is an offending bit of description of the following taser device that is shown in block diagram:

An electronic disabling device includes first and second electrodes positionable to establish first and second spaced apart contact points on a target having a high impedance air gap existing between at least one of the electrodes and the target. The power supply generates a first high voltage, short duration output across the first and second electrodes during a first time interval to ionize air within the air gap to thereby reduce the high impedance across the air gap to a lower impedance to enable current flow across the air gap at a lower voltage level. The power supply next generates a second lower voltage, longer duration output across the first and second electrodes during a second time interval to maintain the current flow across the first and second electrodes and between the first and second contact points on the target to enable the current flow through the target to cause involuntary muscle contractions to thereby immobilize the target.

Remember… if you disagree with your government, you are the “target”.

 

This paper was written about using 40Hz square waves compared to the 19 Hz square waves of the “TASER(®) X26” device…

Conducted energy weapons (CEWs) (including the Advanced TASER(®) X26 model produced by TASER International, Inc.) incapacitate individuals by causing muscle contractions. In this study using anesthetized swine, the potential incapacitating effect of primarily monophasic, 19-Hz voltage imposed by the commercial CEW was compared with the effect of voltages imposed by a laboratory device that created 40-Hz square waves. Forces of muscle contraction were measured with the use of strain gauges. Stimulation with 40-Hz square waves required less pulse energy than stimulation with the commercial CEW to produce similar muscle contraction. The square-pulse stimulation, at the higher repetition rate, caused a more complete tetanus at a lower energy. Use of such a simple shape of waveform may be used to make future nonlethal weapon devices more efficient.

© 2013 American Academy of Forensic Sciences Published 2013. This article is a U.S. Government work and is in the public domain in the U.S.A.

Just from that we know that TASER uses 19 Hz monophasic (single phase) frequency in their devices. They have claimed in the past (as have others) that the specific “shape” of their devices square waves also help in making their devices more “impactful” – however I suspect that all they do is build a circuit (or use a micro controller) to induce a steep pulse at the beginning, ending, or both sides of the standard square wave pattern.  It really does not matter as the prior paper and this next one show that the most efficient pulse is a 40Hz Straight Square wave.

Electronic control devices (including the Advanced TASER(®) X26 model produced by TASER International) incapacitate individuals by causing muscle contractions. To provide information relevant to development of future potential devices, effects of monophasic square waves with different parameters were compared with those of the X26 electronic control device, using two animal models (frogs and swine). Pulse power, electrical pulse charge, pulse duration, and pulse repetition frequency affected muscle contraction. There was no difference in the charge required, between the square waveform and the X26 waveform, to cause approximately the same muscle-contraction response (in terms of the strength-duration curve). Thus, on the basis of these initial studies, the detailed shape of a waveform may not be important in terms of generating electro-muscular incapacitation. More detailed studies, however, may be required to thoroughly test all potential waveforms to be considered for future use in ECDs.

2010 American Academy of Forensic Sciences. Published 2010. This article is a U.S. Government work and is in the public domain in the U.S.A.

 

So, if you want to create a “taser proof” vest or clothing, you have to essentially short out the taser electrodes in a way that does not allow the power to go into your body.  Remember, your body is essentially a bag of somewhat salty water which makes it a rather crappy conductor, unless there is nothing else better.  Typically you don’t wear conductive clothing so you are essentially going to become a conductor… unless you have prepared.  A simple way to do this is to take your favorite jacket, tear out the lining (carefully and in 1 piece) and install carbon tape.

FGQOETQHRWNCQ1D.SQUARE3

Tasers are no match for a real conductor!

Here is an instructable for using carbon cloth tape to create the Taser-Proof Jacket...

After doing that, just make sure you are wearing your jacket whenever you get tased.

March 20

Building a precision “Scroll Saw” or Jigsaw…

Back in my day (think 70’s and 80’s) we used to call table “scroll saws” jigsaws.  We called hand held “Jigsaws” Sabre Saws.  Well, I guess some all powerful authority decided that the names must be “switched all around” and now “Scroll saws” are the table variety and Jigsaws are the hand variety, and, well…

Anyway…

Scroll saws are a very nice tool to have in any Mad Scientist laboratory because of all the various things you can do with them outside of creating “scroll-work”… for example if you create printed circuit boards that are not square, but follow some weird shape due to the enclosure, or if you are making lost foam metal molds, or a variety of intricate cuts…. you need a precision scroll saw. sure you could get yourself a CNC water jet or some plasma cutter device and pay thousands, or… a scroll saw does the job much cheaper.

Problem is that a precision scroll saw is expensive.  Let me explain.

There are essentially 5 types of scroll saws out there. The spring tension saw, the parallel arm saw, the C-arm saw, hybrid parallel saw, and the oscillating saw. All of these saws have their pros and cons, and their basic configurations are shown here. If you look carefully you will see that each has issues with the saw blade that effect the precision of the cut.

constant tension

spring tension scroll saw

 

 

 

 

 

 

 

 

 

 

 

The spring tension scroll saw is a common one from the 50’s and 60’s but is not seen that much today even though the basic configuration is quite simple.  While the blade stays in the same place during the entire period of motion, the problem is that the tension on the blade changes – being at it’s highest when in the down position, and lowest in the up position.  This means that when the workpiece is pressed against the blade, the tension is in a constant state of weak, then strong.  This means that the blade flexes, and the cut will not be as precise as it could be.  It also means that the blade weakens and breaks much earlier than it normally would if it were under a constant tension.  The overall precision of the cut is compromised.

c arm

C-Arm Scroll Saw…

 

 

 

 

 

 

 

 

 

The C-Arm scroll saw as shown in the above picture has the advantage of keeping the blade tension constant, however as can be seen from the motion that is made, the blade position changes with respect tot eh cutting table and work-piece.  While very thin pieces may not be effected as long as the table cutting position stays constant as in the picture, thicker pieces will have issues with precise accurate cuts.  This becomes even more problematic if angles cuts are being used.  This is because the blade cantors back with the C-Arm as it goes through it’s periodic motion.

paralel arm

Parallel Swing Arm Scroll Saw

 

 

 

 

 

 

 

 

 

The parallel swing arm scroll saw is an improvement on the C-Arm, and also represents the oldest of the powered scroll saws in existence. Originally foot-peddle powered, these older saws had very deep throats upwards was three feet, making the offset that occurs when the saw moves upward or downward from center very minimal.  But as you can see in the picture above, this offset becomes much more noticeable as the arms become shorter as in modern day scroll saws.  Still, this is the mechanics of most inexpensive (under 200 dollars) scroll saws you can buy today.  Again, precision is lost because of the offset.

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hybrid parallel arm scroll saw

 

 

 

 

 

 

 

A variation on the parallel arm scroll saw is the hybrid shown here which uses “rockers” to move a cam like series of mechanisms that moves the bald up and down, but again, because the final rockers that attach to the blade are set on a pivot, the blade will have some front to back loss of precision as it rotates around the center of the rocker pivot. more expensive scroll saws employ this method of blade drive to greatly reduce vibration of the saw, however the precision is still an issue because of the aforementioned rocker rotation.

So in all these cases, we have the design of the saw effecting either the tension of the blade during it’s travel, or the actual position of the blade! What we want is for the blade to stay put and only move up and down – nothing else!

There really is only one way to reliably move a blade up and down under a constant tension, without any loss of precision and that is shown below : The oscillating band driven scroll saw.  These types of saws are the most expensive, but are also the most precise scroll saws that money can buy.

oscillos

The oscillating band scroll saw – most precise money can buy.

 

 

 

 

 

 

 

 

 

Here is the deal: I needed a scroll saw.  I wanted one that was precise.  I’m a cheapskate. I like a challenge.

I decided to build my own.

I decided to build a precision oscillating scroll saw using a hybrid design that combines the band of the standard oscillating saw as shown above, and the “main rocker” idea of the hybrid swing arm saw.  Below is a simplified drawing of the saw I am building followed by the actual build itself.

scroll_saw_simple_des

Simplified diagram of my oscillating band style scroll saw. blade guide and other minor items not shown.

 

 

 

 

 

 

 

 

 

 

 

 

My version of the saw uses the rocker from the hybrid parallel arm saw, but then connects to the blade via a steel cable under tension as opposed to a continuous belt or band.  Using brass sliding door pulleys and a tension spring (not shown).  My current build progress is shown below.

scroll_saw3

Collection of junk to start with.

 

 

 

 

 

 

 

 

 

 

 

 

The collection of stuff I had on hand – those aluminum tubes I found in a dumpster next to house construction – by the way: House construction dumpsters are a wealth of great free stuff – but get permission first!  Usually they don’t mind because they have to pay a fee for every pound, and anything you take saves them money!

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cleaning up the tubes (they had cement and oxidized tape on them)

 

 

 

 

 

 

 

 

 

 

 

 

scroll_saw1

cleaned up and cut to length.

 

 

 

 

 

 

 

 

 

 

 

 

By the way, you may have noticed behind the staks of cut tubing that I am building a mini Tesla supply – those door-knob caps are from Russia, bought them about a year after Chernobyl – I wonder where they came from?

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assembling the frame

 

 

 

 

 

 

 

 

 

 

 

 

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It’s coming together.

 

 

 

 

 

 

 

 

 

 

 

 

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The combination of the two sets of struts makes the cantilevered arms of the saw very stiff.

 

 

 

 

 

 

 

 

 

 

 

 

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Northern Tool Pillow Blocks – about 9 bucks a piece.

 

 

 

 

 

 

 

 

 

 

 

 

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Pillow blocks mounted and shaft inserted.

 

 

 

 

 

 

 

 

 

 

 

 

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The section for the rocker arm to be mounted to the shaft. Got to get the welder out!

 

 

 

 

 

 

 

 

 

 

 

 

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Here are the brass pulleys for the saw…

 

 

 

 

 

 

 

 

 

 

 

 

motor

Old dryer motor for power…

 

 

 

 

 

 

 

 

 

 

 

 

 

 

UPDATE! 03/13/2015 – nope, I still haven’t finished this thing, and I really need to because I really need a good jigsaw! Just too much stuff to do!

February 10

Culvert Pipe Food Dryer…

So I got me some leftover plastic Culvert pipe.

FoodDryer4

Plastic Culvert pipe has many uses…other than being for culverts.

What to do with this I thought to myself? Then it came to me… Make a food dehydrator out of it! So this is what I came up with…

FoodDryer

Finished Food Dryer with old blower from a Christmas “Blow up Snowman”

So using a old blower fan I had from a worn out Christmas “Blow up Snowman” some plywood, some plastic window screen, and a couple of “Banned” 100 watt light-bulbs, I proceeded to build this little contraption.

FoodDryer1

Those are real 100 watt “Edison Bulbs” – Contraband these days in the USA…

Using two ceramic light bulb sockets and 2 100 watt light bulbs I first created the lower section that generates the heat for drying. Note that there are concentric ring of holes around the bottom of the pipe and where the plywood meet so that air is constantly moving, carrying heat upwards.

FoodDryer2

single sections of pipe-rings with window screen held in by zip ties.

The pipe is cut into “Rings” that are done ins a way so that can stack like plates on top of each other. Then using plastic window screen and plastic zip ties, you create the food holding trays. As these are all high heat plastic (they withstand up to 400 degrees) they are dishwasher safe!

FoodDryer3

Hot water heater thermostat turns off the bulbs if things get too hot inside.

The blower goes on the top to suction the air out of the dryer and keep a constant flow of air moving. The metal dissipation plate forces the air to move around the food completely so there are not spots where air is trapped. The hot water heater thermostat is there as a safety precaution to shut off the light bulbs if it gets too hot inside.

I have dried tomatoes, bananas, many spices, etc in this dryer and it works very well. I would probably make the stack-able rings a bit more stable if I were to do it again, but all in all this is a single day project that can really add to your food processing skills and give you a bountiful harvest of dried seasonings, “sun dried” tomatoes, and other dehydrated delicacies!

-DTM.

February 7

A Cold Smoker for Meat and Cheese…

I like a good smoked cheese… Problem is, when you buy it at the store, it is very expensive.  Then you find out (if you care to look) it’s not really smoked at all! (at least not most of them).  No, instead most so-called “smoked cheese” you get at the store has been “Flavored” with liquid smoke, and then it’s been brined in a “colorant” that makes the outside brownish to give it that “Fresh from the smoker” look.

Pish -Tosh to all that! I want real smoked cheese!

hotsmoker

This can smoke your ribs… but not your cheese!

What to do?  Well you cant smoke cheese in a traditional hot smoker, such as a bullet smoker:

Not unless you like a burned, melted mass of glop.  I don’t prefer that…

No, Cheese must be smoked in what is known as a “Cold Smoker”.  I decided I wanted to smoke cheese and a variety of other things so it was time to build one of my own. So I decided to build mine as a 2 by 2 by 4 foot box out of scrap plywood as seen here.

 

 

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The Back of my smoker sticking out of my workshop on a cold day.

Here are several more pictures of the smoker…

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Front of Smoker

 

 

 

 

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Inside shot of the smoker showing racks and the smoke distributor on the floor.

 

 

 

 

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This shows the smoker with the racks and the distributor removed. Note the creosote collector – some spilled out when I was moving the smoker.

 

 

 

 

 

 

 

 

 

 

 

 

The smoker has a “smoke distributor” on the bottom – which is basically a false floor with large holes cut out to allow the smoke to permeate the entire box.

The smoke pipe runs down the entire length of the smoker so that the smoke cools, and so that creosote (which makes food bitter) is condensed and collected in a little tuna can at the bottom.  This has to be cleaned out after every smoking session.

The racks are 1.5 inch dowels that sit in cutouts on the side of the smoker.  The food to be smoked can be laid directly on the dowels, or (in the case of cheese and smaller items) placed on dollar store cookie cooling racks that then sit on the dowels quite nicely.

The door seals shut by using 2 lengths of cotton clothesline.  The clothesline seals against the door when it is shut for more or less an airtight seal.

smoker3

The Smoker loaded up with some chicken and a small turkey.

When loading up the smoker with meat, I always keep a drip pan underneath to try to keep as much of the raw meat drippings getting in the wood.  You cant stop it all. so you wipe down the inside with Clorox between smoking sessions (not needed when doing things like cheese or when smoking salt).

Now for the most important part of the smoker – the smoke generator!

The smoke generator is the box that sits atop my smokier, raised up in the air.

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The smoke generator.

 

 

 

 

 

 

 

 

I could have gone the rout of using a commercial smoke generator such as the “Smoke Daddy” Cold Smoke Generator but that would not be in keeping with my nature of “Build your own” – besides, the smoke daddy compels you to use their special “smoking wood sawdust chips”.  I wanted to use any kind of wood I can purchase from local sources, or cut from trees such as apple orchards, etc.

So, I built my own from an old Army Equipment box.  The way a smoke generator works is by using a negative pressure venturi inside an enclosed container which is where the smoking chips are burned without oxygen. The box is an hardened aluminum box with snap-down lid. The iron pipe goes through the center of the box, and where it passes through the box there is a hole. The arraignment looks like the schematic shown here.

SmokerSchematic.jog

The venturi (the blue tube that comes to a point in the diagram) pulls the smoke and keeps just enough air flowing into the box to keep the coals going once they are started from the two “touch-holes” on the outside of the box.  What happens is that the air moving through the venturi causes a vacuum in the larger tube which then pulls smoke and air from the seal box into the larger tube which then enters the box.  The larger tube is over 4 feet long so that the smoke cools down, and releases much of it’s creosote (a bitter chemical you don’t want on your food).

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Smoke Meat and Beer… Mmmmm!

The smoke then proceeds into the smoking box, where it emits from the base as cooled smoke.

Shown here, I am using Cherry Wood Chips purchased at my local “Harris Teeter” Grocery. The large beer next to the smoking chips is a delicious brown ale my brother Jamie made and bottled himself – nothing goes better with smoke and meat than a good, ice cold brew!

I shall update with more pictures of the smoke generator as I get time…

-DTM

January 26

Converting an inexpensive AC Welder to DC Service…

About 9 years ago I converted my standard Lincoln AC “Buzz Box” Welder into DC Service. I did this by building a massive full wave bridge rectifier. It has provided great service and welds very nice – DC welding is acutally quite a bit easier than AC welding, and in fact, this DC full wave Bridge is clean enough for Tig welding should I ever get the bug to do that.

Here is how I did it. (Excepted from my old original website hosted on Comcast – and it is still there even though I haven’t been a customer in over 9 years!)

Welding can be done with AC but for better welds and for work on thinner sheets of metal, DC is needed. Lincoln sells a inexpensive AC arc welder that can handle as much as 225 amps of current at about a dollar per amp. A DC welder of this current can cost twice as much, and a Mig welder of this current is way more. I decided to buy the cheap Buzz Box and then convert it to do what I want. First I built this DC arc conversion. Next I will build a Mig and Tig extension and then I will have a fairly complete welding system for very little money.

The basic parts – check out those massive diodes!

I acquired these four 300-amp,200-volt diodes from Ebay for $7.00 apiece. They originally sold for $90.00 each. You can get this stuff cheap and there. The old transformer will be used as the choke coil (see circuit diagram).

Close up of the diode, these suckers are Huge! The measure in at 3 inches across.

The heat sinks for the diodes and the cooling fans in the back ground.

The heat sinks are prepared.

Using copper strapping to make the connections have as low resistance as possible for the massive welding current.

The terminals and heat-sinks must be connected such that the heavy current (as much as 225 amps) can flow unrestricted, and so that cooling is possible in both air or in a oil bath, and so that the whole is structurally sound. To insure all of this I used both aluminum and copper strapping scavenged from the transformer shown earlier. Notice how the aluminum is wrapped with the copper.

Below is a diagram of the full wave bridge. Again, while the circuitry is simple, the actual physical construction is challenging due to the heat dissipation requirements and the current carrying requirements.

Schematic Layout

Completed Rectifier in the welding cart.

A view of the completed air cooled full wave bridge mounted on its nylon header. The header is made from a nylon kitchen cutting board. The box is an old main-frame computer power supply box.

Finished

The finished DC rectifier showing connection end

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Rectifier showing Choke and cooling fans

 

This welder has given me 9 years of great service – never overheated, and I have never had any issues with the rectifiers. A great way to build an awesome system and save money. Your just not going to be able to buy something of this ruggedness without spending a ton more money.

-DTM