As a builder of weird musical instruments, I like it!
This is pretty innovative and looks suited for the specific conditions in the video. Necessity is the mother of invention, and if it works, it works. I am no stranger to building unusual musical contraptions that have raised a few eyebrows, but as I learned programming, my build projects became less frequent and replaced with software. I might have instead copied the knee-levers under a pedal-steel guitar for complete hands-free operation, but if you're standing like in the video, I guess that wouldn't work. I also use my right thumb too much to charge it with another task, and the hand motion required to actuate the bar would definitely affect my playing. It is certainly not something you could just start playing with, you would have to alter your playing style.
I can see how this would work for a two keyboard setup, but if you're using one keyboard split, you wouldn't want the pitch bend to affect the bassline or chords or whatever your left hand is playing. I just use grace notes to mimic bends anyway, but if I really needed a hands-free pitch wheel that bad, I'd probably just write a program to trigger on a message from my expression foot pedal, cancel the expression message, and output a pitch bend message instead. You'd have to choose either up or down, not both, because centering wouldn't be possible. Similarly, a simple on/off pedal could be used to trigger multiple bend messages on a curve over time - like a time specified by the user as a variable or something. Program a linear, or exponential curve, or have that as another user option. Either way, you could also program it to not affect notes below the split, and even have the user specify where the split is. My point is, that there is a lot you can do with software and off-the-shelf controllers before you need to resort to building/buying custom mechanical actuators. It's not an old mechanical punch-tape fed player piano we're modifying here, it's a computer. Software can just tell it to do anything.
None of that means I don't like it, though. Because I do. It's awesome and strange, and not unlike stuff I've built, to be honest. It satisfies its intended purpose, and most certainly is not boring. I just don't see it gaining huge popularity as a product over software and standard controllers. It's purpose is too specific to a two-keyboard setup, and not really user friendly if it has to tap directly into the keyboard's pitch bend and modulation circuitry as described. I might have just had it send midi messages to the midi-in port.
That wasn't even my two cents.. that was like a quarter. Sorry about that. Now, please excuse me while I go write code to turn my volume pedal into a pitch wheel
