Solid State Epee Tips - Any Interest?

[Robert Smith]

Originally Posted by DHCJr

The distance is not there that there be adequate distance. You could require 0.1mm distance would be enough for seperation. In fact one of the requirements that was passed by the FIE Congress was the use of a Foil tip that required 2mm of travel. This was not implemented, only because the requirements did not get sent to the manufacturers.

Having a tip that you can just hit with 750 grams of force and only move it 0.1mm will not fly. The rules are not there because of the requirement of the springs, the springs are there because of the requirement of the rules.

If you can get the 750 grams, the cost down, the grounding problem and the travel you would have something.

In that case I'm missing something quite important here. What is the purpose of the travel? Someone suggested that it absorbs some of the impact of a hit, but that sounds unlikely in the first place, and certainly not an adequate reason for requiring it. Why 1 mm - 1.5 mm? Why not 01. mm, or even 1 cm? I'm having trouble envisaging a purpose outside of the mechanics of making / breaking a circuit. Enlighten me, please, because if it is truly essential, then there ain't no getting around some form of spring.

[DHCJr]

What they were doing was to show that you were actually moving forward. Remember is a point weapon. That is one of the problems right now with the Foil. How the tip is set up, you just need to jar the tip, which can of course be done with a flick. How much travel can you have. There is a limit, so the 1mm was a compromise.

My knowledge is conjecture and some past readings. There is no one around now who was around when this was first decided. 1936 may have been the first official FIE electric epee, but it has been around over 100 years.

[Purple Fencer]

Originally Posted by DHCJr

My knowledge is conjecture and some past readings. There is no one around now who was around when this was first decided.

Not even Donals Benge or Joe Elliot?? *ducks & runs*

Actually...I'm wondering if Andy Shaw might know...

[acaba]

I have another question about the solid state tips. Would they work with the boxes? I don't know what kind of material you would be using, but I expect that there would be some current leakage even when the tip is not depressed. Would the boxes handle that leakage current, or would they do something strange? I remember hearing one box manufacturer talk about how they register touches, but since I'm a mechanical engineer, not a EE, it didn't stick in my head. Just another thing to check/think about.

[andrewmcleod]

The other problem is quite obvious when you consider the resistance-travel curve of a spring tip. At 0-1mm, resistance is effectively infinite. At some point, resistance drops enormormously as the springs contact to maybe a few ohms (with bad contacts). This curve will be nearly discontinuous - there will be a sudden changing point you can easily measure.
Consider such a plastic as described that drops in resistance as hit. As you reach a certain travel point and begin to compress it there will be a continuous (though not neccessarily linear) drop in resistance. There will not be a sudden sharp boundary to measure, so you will just have to decide that for instance where resistance has dropped to <200ohms to register a hit. But then you have to measure resistance precisely. Also spurious resistances in the spools, wires, weapons, how good the batteries in the box are etc. will start to play a larger role...