Test box

Discussion in 'Discussion Archive' started by Purple Fencer, Apr 4, 2002.

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  1. Purple Fencer

    Purple Fencer Podium

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    Guys;

    Does anyone know where I could get a test box that does more than just see if the spring works? I'm looking for something likr an armorer would use at a NAC...test the body cords, lames, see if a weapon is firing off target lights, etc.

    Nothing on the extreme level of one of Dan DeChaine's rigs (Lord knows what he's come up with now), but something I could use to better my armoring work.

    Thanks
     
  2. oiuyt

    oiuyt Podium

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    I believe they all roll their own. The circuitry involved REALLY isn't that complicated, and parts are conveniently located at the nearest radioshack (which is what, 5-10 minutes from you?). Throw a couple of sockets into a RS project box, run a bit of wire to connect them appropriately to batteries and posts which you can clip a multimeter to and you're set. Put in a selector switch to flip between which lines are connected to the posts and you have basically what the NAC people have.

    I'd suggest designing/building it on your own. If you really want someone else's, Bill Hall I know has made them for some of the clubs around here (New England). His email is [email protected] No clue what he charges, but they look good and I've only heard good things about them.

    I LOVE Dan's.... any test box that includes not one but TWO alarm settings is just great (especially when one of them involves the box screaming to be put down....).

    -B :)
     
  3. Methix

    Methix Made the Cut

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    I'm extremely fond of the Zivkovic test boxes. On top of testing to see if they work or off-target, it has a built in timer so the light will stay on for a sec. Really nice for troubleshooting foils that go off when you beat it on your foot, but don't give a constant white light.
     
  4. sallearmourer

    sallearmourer Armorer

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    Most of us built our own Sam.
    I am having one being built by Joe for Janet. He won't built it for me but for my wife. There is going to be a armourer college offer this summer at Col Springs for 285.00 for level 3 certifiaction. It on the Coaches college web site.


    Tim :D :D :cool:
     
  5. sallearmourer

    sallearmourer Armorer

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    Go to the allstar of Great Britian they sale a nice setup. it made by Allstar. It's does body cords.

    tim :D :D :cool:
     
  6. Tim McMackin

    Tim McMackin Rookie

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    Barry Tice had a simple but useful design at his website at pointcontrol.com, but that site doesn't seem to be working.

    It was a box that had a 3-prong connector for the body cord, so you would plug the body cord in and plug the other end of the cord to the foil. What it did was check for a broken connection between the two leads on the foil blade. If the circuit was broken by pressing the tip down or by a break in the wire, it set a buzzer off for a second. Also useful for testing body cords; all you had to do is plug it into a weapon that you knew worked and wiggle the body cord around and see if the connection broke and the buzzer went off.

    So if you have a little electronics experience you can make a simple one. The parts cost a few bucks at radio shack; it takes a $1.50 microchip, some generic resistors and capacitors, buzzer, battery clip, and a box to put it in. I had to modify it a little to get it to work properly, though.

    If this sounds like something you want, I could email you the PDF file with the design. I can't imagine Mr. Tice would mind; it still has his name and information on it.

    Does anybody know of a design similar to this one? It almost makes a workable wireless training tool. Plug it into a working foil and it buzzes when the tip is depressed, so you can practice to see if your flicks or *real* touches would have set off the machine. We use it at the club with rookies occasionally so they know what it takes to make the electronic foils register a touch.

    Tim McMackin


     
  7. neevel

    neevel Armorer

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    For doing serious armory work I'd strongly suggest something that connects to an ohmmeter to give you a readout of the actual resistance, rather than something that shows a simple LED/buzzer make-break state. Seeing what the ohms resistance is in a piece of equipment is an invaluable indicator of incipient problems, and allows you to catch them before they get bad enough to actually cause problems with strip equipment.

    Consider body cords as an example. The rules limit on body cord resistance is 1 ohm. It's possible for a cord to show far higher than that on an ohmmeter and still function with a scoring set or an LED. Being able to see that the resistance on a line is at 10 ohms rather than 1 ohm (or momentarily jumps up from 1 to 10 when the cord is flexed) is a warning that a fault is starting to develop: loose screw, partially broken wire, corrosion. Same goes for weapons-- 25 ohms in a foil means that something is wrong, even though it looks fine on an LED box (it should be 2 ohms or less).

    Lames are another case where it's good to know exactly what the resistance is. A lame that shows 0.5 ohms and a lame that shows 4.5 ohms both pass, but that 4.5 ohms indicates that either it needs a really good washing or will have to be replaced soon. A tester that only gives a binary pass/fail (such as units that Allstar and Uhlmann make) won't give you that kind of information.

    So, you really need to get yourself a decent digital multimeter and a number of stackable bananna-plug leads and alligator clips. Bill Hall can sell you cap and crocodile clip that'll enable you to use any 500 ml water bottle as a lame test weight. With these, you can carry out any electrical test needed for weapons, cords, reels, and the basic aspects of scoring machines. All the other doodads, from the simplest 6-position switch box to one of Dan's testers, are nothing but labor-saving devices.

    -Dave
     
  8. Tim McMackin

    Tim McMackin Rookie

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    Yeah, neevel, that's a weakness in the buzz-box design. It does catch problems like broken connections, but not the more subtle changes in resistance. Plus, I have no way to know if the buzz box is as sensitive as the scoring box in detecting the on or off threshold.

    The ohmmeter wouldn't catch the really quick breaks in contact, though, would it? A lot of times we have a foil that is working well unless it is hit suddenly enough to shake a connection loose for an instant. I may have a cheapo multimeter, but it's tricky to tell when the resistance jumps for such a short time.

    That makes me wonder if it is more common for a given piece of equipment to deteriorate slowly (like the aging lame example) or fail all at once (like a foil with an intermittent off-taget light).

    For example, is a body cord more likely to lose the connection completely due to a break or to wear down to the point where it's holding on by a thread, causing a higher resistance? I normally find the breaks, but of course I may only be finding the problems I'm looking for. I suppose it's most likely that it would only break if it had deterioriated first. <img src="confused.gif" border="0">
     
  9. neevel

    neevel Armorer

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    Simple LED (and even the Faveros with their handy 1-ms break lights fall into that category) boxes do not in any way have the same make/break thresholds and tolerances as scoring machines (you can find them all in the rulebook).

    While a really cheap (under $25 or so) DMM may very well be too slow, a good one will be plenty fast enough to catch brief breaks-- in fact, it's the ideal tool for spotting transient problems (well, assuming we leave handheld digital oscilloscopes out of the picture as overkill :) ). Something like a Fluke 110-series meter would be ideal, but there are less expensive ones that are adequate.

    Body cord faults are almost _always_ gradual- stressed wire will fail a few strands at a time, until all the strands are broken. This would show up as the resistance progressively climbing higher, if you were to just monitor it but not do anything to fix it. If you don't regularly check your cord with a meter, however, then you won't find the problem until it reaches the point that it'll show up on an LED box or a scoring machine. This is why we test fencers' body cords for resistance at NACs-- it drastically reduces the number of strip calls, or instances of referees depositing reels and floor cords at the armory that they think are bad, when was actually an intermittent body cord problem.

    Weapon problems are also frequently gradual. That problems arising from dirt or corrosion in the point and spring would have an incremental onset is obvious. Things like a broken solder joint in the contact cup can also happen over time-- the solder can start cracking, which will show up as increasing resistance, before it breaks completely. Same goes for breaks in the wire itself, which can start as a crack that eventually propagated across the wire. If you take a foil that works fine on the strip, but see with an ohmmeter that the resistance when the tip is depressed is 50 Kohms instead of in the 'infinite' or Mohms range, that's a sign that the insulation has started to get damaged somewhere and the weapon will likely develop a more serious B-C short that will prevent it from registering touches.

    The upshot of this all is that, for anyone doing serious armory work, a decent DMM is almost as essential a tool as a set of tip screwdrivers or a blade-bending jig.

    -Dave
     
  10. Link14

    Link14 Rookie

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    Maybe you guys can help me out on this one. I've been thinking about making a test box that connects to my ohmmeter instead of just using the test leads. Then I started thinking that the voltage on my ohmmeter (9V) is higher that what's used on the strip (6V). So does this mean if I'm testing my lame with the ohmmeter, it might not pick up on an above 5 ohm area because the 9V battery is "pushing" more current?
     
  11. neevel

    neevel Armorer

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  12. DHCJr

    DHCJr Armorer

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    1) I would suggest an analog over a digital as far as meters go. You would need a very fast (expensive) digital to see momentary break, where a inexpensive (<$30) analog would catch more watching the needle.

    2) The AllStar has only a foil connection for two-prong. You would need an adaptor for any other.

    3) Most armorers do build their own. A good first box to build would use a 6-position,2pole rotary switch connecting A-A,B-B,C-C,A-C,A-B,B-C. This is fairly simple, the cosmetics is the most work as well as putting in each of the foil connectors.
     
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