I was recently asked if it was legal to press the clock with one’s elbow. I thought that the answer might come under annoying the opponent, but really wasn’t sure, so I thought I’d post here.
Alex Relyea
I’d say it is clearly illegal. Both USCF rules and FIDE rules say you must operate the clock with the same hand that moves the pieces. An elbow is not a hand.
Speaking of non-standard interactions with a chess game…do I have to say j’adoube if I adjust a piece by blowing on it instead of touching it? (Hey…if you don’t me to blow your pieces, don’t bring a non-weighted set…).
Will the touch sensor on a Chronos clock register an “elbow tap”?
As an example (a bit extreme) that not every answer a 100% yes/no, if you are an amputee at the wrists then you may need to use an elbow for the touch sensor.
But will the sensor actually register the tap? For example, if I touch a piece to the sensor, there is no change in the timer. Is there enough electrical conductivity to produce the change in the mechanism? Must one “double tap” the sensor with the elbow to make sure?
How many angels fit on the head of a pin?
What color angel?
That is trivial?!
Rather than engage in scholastic philosophy, has anyone done an empirical test to determine if the touch sensor will work if touched by an elbow? I do not own a digital clock with a touch sensor, or I would experiment with it to see what works and if there are limits. BTW, the number of angels was deduced. Their color might only be important if one is using the new Z clocks. 
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Maybe I’ll make some moves with my elbow, to get around this restriction of “same”. 
Even assuming you can pronounce it accurately, using the non-English word “j’adoube” is awkward, pretentious, and confusing. 
Players can simply say “Adjust”.
GM Gregory Serper adjusts pieces more frequently than the average GM does. But when adjusting a piece, Serper never grasps the piece between two fingers. Instead he only touches the piece with the back of one finger; to visually assure he is only adjusting.
You are making my bishop nervous. 
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I look forward to seeing the video on Youtube.
A bare elbow will cause the touch sensor Chronos to change. I picked up the clock to test this. It is difficult to imagine how this would play out in a tournament game. If a player is an amputee and the prosthetics used to move the pieces would not cause the clock to register couldn’t there be an accommodation made available for this player? If I were the player’s opponent, I would be willing to touch the sensor for them (without being conveniently missing in case of time trouble).
I will assume that the question legitimately involves an amputee with a prosthetic and a touch-sensor clock, as opposed to being a wacky “I want to do something bizarre” hypothetical.
If the player with the prosthetic has a digital clock capable of increment or delay that suits his needs, and the player is assigned White, then I would rule that his inability to use a touch-sensor clock without extraordinary/extreme measures (and I consider having to use an elbow to press the clock “extreme”) trumps Black’s right to choose the equipment used for the game.