How do electronic sensing socks / chest protection sensors work in sport competition?

Question

I recently read about Sockgate and was curious how the vests/socks that taekwondo sport competitors work. I understand that there are purely electronic systems and pressure based ones.

I assume that other martial artists may use similar equipment to judge hits. (I could be wrong)

I searched around and got brief information about how new ones were introduced, that addition additional sensors may be used to cheat (contested), etc. I even saw a partially deconstructed vest which contained electronic sensing bars running in parallel up and down the chest protector.

But no where was there an in depth explanation from what I could find of what is in the sensor socks / how they are made / what prevents people from modifying them to increase signal range etc. How do pressure vests avoid issues of movement causing pressure shifts etc. Essentially I'm interested in learning more about how the system works in the nitty gritty details. I'm not planning on making one but I would like to understand exactly how they are made how the system works etc. In martial arts the amount of force is also relevant which I think is interesting whereas most electronic systems rarely take that into account. Also why have they not be added to the head protector?

I understand that some of this information may be proprietary and that may be part of my difficulty in learning more.

By the way I am not looking to cheat etc, I do not practice taekwondo I was talking to a friend about it and became interested in the sensing systems. Which also is why I may be using the wrong vernacular.

Thanks in advance.

Answer 1

I'm guess that "Sockgate" is referring to this incident? There's a good description of the "SensorHogu" technology in this article. They use piezoelectric sensors, which is the use of crystalline materials that react to impact with releasing a small burst of electricity. They require a sharp impact, which matches with what one wants for a tournament setup. Regular movements should not trigger it. They also have a brief discussion of how they feel that head sensors are not necessary because strikes in that area are more readily scored (they don't elaborate, but I believe it's a matter of fewer things getting in the way of the judges seeing the hit due to the mechanics of getting your foot that high plus the rules requiring less forceful contact for head blows due to concussion fears).

I have yet to find a discussion of the technology for restricting striking areas (that's what the sensors on the feet and gloves do), but my suspicion is that they probably use RFID. That would make it a passive technology, and one which really cannot be changed dynamically in the field. There's no way to "boost the signal" because the vest is the part that actually sends and receives the signal. It's robust against impact if done properly. And it requires no power source on the striking implements, which means people aren't throwing battery-weighted punches or kicks. A quick swipe of an RFID wand should be enough to detect any additional illicit sensors (I don't know if that's how the "Sockgate" competitor got caught or if someone noticed a dodgy hit and requested that the equipment be examined). And it's very short range, which, combined with the impact sensors, avoids the point being suggested when a foot just passes by the target area.