How Sabre Electric Equipment Works

Discussion in 'Armory - Q&A' started by kookoo, Nov 17, 2018.

  1. kookoo

    kookoo Made the Cut

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    Can anyone help me understand how Sabre electric fencing equipment works? I think I'm struggling with understanding how the lines are connected in the scoring box so that circuits can be completed. Does anyone have a guide or diagram I can use to try and understand? Even a book recommendation would do.

    I'm struggling to understand the electronic circuits involved and especially the connections made between opposite fencer's equipment and the scoring box.
     
  2. kookoo

    kookoo Made the Cut

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    I'm attaching what I think happens, but I'm still not sure about the paths of circuits.


    Weapons aren’t connected which means there’s a closed circuit and the yellow lights are on. Current comes from the B line and goes back using the C line which leads to the yellow lights to be off. Opponents lines are A', B', C'

    Current goes through the left B line and goes round in different ways:

    Nothing, BCC’B’ flowing blissfully, no lights

    Hit opponent’s blade or guard, BCC’B’ still flowing blissfully

    Hit opponent outside of target area, BCC’B’ still flowing

    Hit opponent on lamé, cuff or mask, current goes through the path of least resistance which means the current goes through circuit BA’ which lights up red if red fencer’s weapon hit’s opponent on target?
     
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  3. Purple Fencer

    Purple Fencer Podium

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    A more simplified version....

    Power comes into the weapon through the B socket and immediately goes to ground through the same weapon's C socket. Unlike foil, the blade never carries power when it is not in contact with the other fencer somehow. The blade only carries power if there is contact with some part of the other fencer's weapon system (weapon or lame/mask/cuff).

    If Fencer A hits the blade or guard of Fencer B, nothing happens because power is still going directly to ground (via B's C line)...the same as an epee or foil hit to the guard.

    If, however, Fencer A lands a hit on B's mask, cuff, or lame, power is redirected through B's A line, thus lighting up the appropriate light on the box.

    Keep in mind that if A makes contact with B's blade and something like exposed tang on B's weapon is touching his conductive parts, it'll register as a hit for A, because that contact provides a pathway for his hit to register.
     
  4. kookoo

    kookoo Made the Cut

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    Thanks. That clarifies it a bit, but I'm not interested in the simplified version. I want to understand more how exactly lines are connected to each other and in what way in the counting box. It seems like explanations are nevermade about how lines of yours and your opponents are actually connected? Is there an electronics diagram that shows it?

    I'm just not satisfied with the explanation. So current comes into the weapon through the B line and then goes back through line C which then goes to the opponents B line through the box and then back through the opponents C line and through the box back through my B line, and so on if the blades aren't hitting anything?

    If I hit my opponent's mask though, current goes through the blade, through his mask, through his A line, through the box which then a light is hooked onto that circuit so it lights up for me?

    Yes I figured that much about the exposed tang, hence why metal pommels aren't used on sabres?
     
  5. DHCJr

    DHCJr Armorer

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    I'm afraid you all got it wrong. You have to go back to when Sabre was first electrified and compare it to how Foil works.

    A Foil works by direct current coming from the B line and when there is a break while the tip is in contact with the jacket a valid touch is indicated. Now Sabre was the opposite, when the blade (Ground C-line) came in contact with the jacket and there was a break in the sensor a valid touch was indicated.

    Now since there should now be a permanent short between the B & C, it doesn't matter and the rules have dropped the requirement for the current to come from the ground.

    If you want a more technical explanation, you should go to the rulebook page 183 US Fencing, 84 FIE English, 68 FIE French.
     
  6. kookoo

    kookoo Made the Cut

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    Thank you I’m still struggling to understand this all as multiple circuits.

    Ed and Li are connected. Ed’s on guard and so is Li. At that point, there is a circuit that’s connected for Ed and has current going round which goes through BC and the scoring box and loops around. Separately there is another circuit looping around through BC of Li and looping around.

    Ed now hits Li’s lame. What’s happening in terms of circuits?
     
  7. neevel

    neevel Armorer

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    A new circuit is closed through Li's A-line from Ed's sabre, which is what signals the hit.

    One item to be corrected from your diagram is that you can't really consider a scoring box as an analog circuit. Scoring apparatus are essentially inputs being fed to a microprocessor via ADCs (and prior to microprocessors scoring boxes were still digital logic, just being executed either by discrete transistors or relays). The processor is checking what the state of the all the inputs are together, and executing logic that will signal a touch if the right combination of states from all the inputs is seen. The logic for Side 1 to register a touch on Side 2 is summed up as: If Side 1 B-C inputs are in contact with Side 2 A input, and Side 1 B-C inputs are not simultaneously in contact with Side 2 B-C inputs for a time window between 4-15 milliseconds after Side 1 B-C makes contact with Side 2 A, then signal touch for Side 1. (See the rules sections Donald referenced above for where those conditions are laid out).
     
  8. kookoo

    kookoo Made the Cut

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    Thank you, that helps.

    “If side 1 BC inputs are in contact with side 2 A inputs. “ how would all of that be in contact in the box? Are ADCs connected to each other or is that done in the software so the microprocessor knows how to pass current?

    I clearly need to read a book about electronics. Will do some digging, ideally I want to fully understand how the entire Sabre apparatus and scoring machine works. If only I could get my hands on a circuit plan of a scoring machine which also includes Sabre.
     
  9. neevel

    neevel Armorer

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    The logic is executed in the processor. In general, the implementation of modern electronics is as much about embedded software as it is about circuits. Buying an Arduino and starting to play around with projects for it is a good way for a hobbyist to begin to understand how things work.
     
  10. ktinoue3

    ktinoue3 Podium

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  11. kookoo

    kookoo Made the Cut

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    Thanks. The problem is I think that the Sabre function doesn’t work, but actually the plan is to use that Arduino project to make a Sabre one so will bother some other kind folks in electronics forums instead.
     
  12. kookoo

    kookoo Made the Cut

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    Thanks neevel.
     
  13. kookoo

    kookoo Made the Cut

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