VERY OT: wireless fencing transmitter reciever?

[Hal]

well, it turns out that wireless fencing is getting more and more popular, and in use in major tournaments now, such as World Cups.  However, I would like to build one to play around with in my club, and have a little fun experimenting with radio stuff...

pretty much, the idea behind this is to relay 3 channels, from each side to a machine.  The machine does all of the work, so all it would need is continuity between 3 channels on each side....

okay a little more detail.  The body chord is plugged into the weapon, and lame.  this has three prongs, that goes into a retractible reel, and then a floor chord to the machine.  The reel and the floor chord simply connect the fencer's body chord to the machine...in theory, one could plug their body chord straight to the machine, but it would be extremely clumsy. So, I just need something to maintain continuity between the body (in a belt-pack) and the machine...

The question of if its one or two way is my main concern, and I think I would have to do some more research of my own before I continue.  I believe there would have to be two way communication, and it would have to be almost instintanious, with as little noise as possible.  However, these last two requirements could be ignored for size and simplicity.  


any ideas?  I imagine it would be similar to a guitar transmitter.......

thanks

[niftydog]

any ideas? I imagine it would be similar to a guitar transmitter.......

Yowsers... possibly you could modify one...

how many different "alarms" are there?  Like, does it produce different scores from contact with different body parts?

I always thought there was just one "buzzer"...

It will require some work... have to detect a hit, create a signal to send, send, receive, then some processing on the receive end to actually score the hit!

If you can find some info on how the commercialy available products work it would help.

It's pretty funny what you get when you google "wireless fencing"!!

[Hal]

well, actually I wouldn't need to "process a hit" thats all done in the "machine," which I will probably try to build at some point.  Thats actually really complicated, becuase the timing has to be perfect.  Retail, they cost around $750, up to about $3500.

the wireless unit would connect to a sword, and a lame, which is a metal jacket.  to sum it up, there are 3 weapons.  The simplest, Sabre, has 2 wires going to the weapon, and one to the metal jacket.  when the 2 wires in the weapon are not connected, a light goes on.  When you plug them in, they cross, and the light turns off.  When you hit your opponents metal jacket, with any part of your blade, your colored light goes on.  When you toutch your own jacket, a small grounding light goes on.  Once again, this is all taken care of by the machine.  You just need to plug the three lines into the machine.

Epee and Foil, the other two weapons, also have 3 lines.  In Epee, two are used for a button on the tip, and a third is used to ground the guard, so it doesn't go off if your opponent hits it.  Foil also has a lame for target, and a button together.  a hit on the lame scores a point, and a hit off of the lame, which covers only the torso stops the action, but scores no point (there is a different light).  So yea, thats pretty much it.  No Buzzers or anything....

the evolution of the fencing machine is actually pretty funny.  The first ones used tubes and relays, before semi-conductors.  The relays were only accurite within about 100 miliseconds, which is why "double toutches" developed as part of the game, in epee.  Now, even though accuricy up to about 1/1000 of a second can be achieved, this concept is still around.  A lockout time of 150 milliseconds is used (I think thats the time).  

so yea, back on topic, continuity would have to be maintained between the machine and the fecners, on 3 lines.

[Paul Perry (Frostwave)]

This is an extremely interesting question! The only way to avoid any wires, in my opinion, is to consider the two bodies as capaitors. And each person has an oscillator n them, wiht the persons self-capacitance as part of the timer. And on contacting the otehr person, this shifts the freq suddenly (like when you touch a RF theremin antenna).
Similar to some touch plate switches.
It is doable, definitely.

[Hal]

huh?

LOL  I kinda see where you're going with this, but the point isn't to avoid _all_ wires, its just to bring the 3 plugs from the wire hanging out of hte fencer to the machine without a reel in between....

[Paul Perry (Frostwave)]

huh?
LOL  I kinda see where you're going with this, but the point isn't to avoid _all_ wires, its just to bring the 3 plugs from the wire hanging out of hte fencer to the machine without a reel in between....

Ah, but you don't see WHY we have to go there. If i am correct, you need to have a circuit that is closed when you hit the other person. Can this be done with RF?
Well, maybe it can. If one person is energised by a small RF signal, it is certainly true that more signal will be piced up by a receiver on the other person when the contct is made.