[Dennis] aims to make robotic control a more intuitive affair by ditching joysticks and buttons, and using wireless gesture controls in their place. What’s curious is that there isn’t an accelerometer or gyro anywhere to be seen in his Palm Power! project.
The gesture sensing consists not of a fancy IMU, but of two potentiometers (one for each axis) with offset weights attached to the shafts. When the hand tilts, the weights turn the shafts of the pots, and the resulting readings are turned into motion commands and sent over Bluetooth. The design certainly has a what-you-see-is-what-you-get aspect to it, and as a whole it works much like an inverted, weighted joystick hanging from one’s palm.
It’s an economical way to play with the idea of motion sensing, and when it comes to prototyping, being able to test a concept while keeping costs to a minimum is a good skill to have.
“Fancy”? I thought the IMU had become mostly blasé as it is so ubiquitous now (every phone, car, and most tablets).
Brilliant idea. I will try it out. The mobile phone usage is simple – or take a microbit – all done and documented. Here it is a minimum component solution and genuine. Great. The only change I will do is to take the wireless out and replace it by infrared.
brilliant… I would not say that.
This “system” doesn’t work as you always want it to be.
I know this by experience because as a youngster I’ve experimented with a similar setup. That was 30 years ago, back then we didn’t have small and affordable IMU’s yet.
The problem with potentiometers is that they have some slight mechanical resistance, so turning the pot takes mechanical effort. Doing small movements will therefore not be registered unless you make the weight a bit heavier.
But a heavier weight will result in more overshoot of the parameter you are trying to measure. So you must find a ballance between “swing like a church bell on sunday morning” (when you move your hand quickly) to insensitive to small movements.
But If you are willing to accept these issues, it will work just fine.
The best way would be to make it optical, using an LDR a small lightsource and a circular shutter passing between them. The shutter blocks the light analog to the angle of the system. This can be made almost friction less (needle bearings) and can therefore be kept very small/light. Some form of dampening must be added to prevent overshoot, a drop of oil could do the trick. Instead of optical you could also make it capacitive, just like the old adjustable caps from analog radios.