Why Hall effect sensors used so rarely in human input devices (HID)?
The only two i know that (probably) user hall effect sensors:
- Thrustmaster t16000m - a joystick, only uses hall effect sensor for the x and y movement of the joystick, it also supports rotation of the stick, but that's handled with a potenciométer, it needed a contact cleaner after only 2 months of use (i own one), i'm not sure isn't a magnetic sensor used for that
- Haken continuum - a very expensive musical instrument I haven't had the chance to try one, they are super expensive, starting at $3390
If you'd say, it's because magnetic fields can disturb the device, don't forget that we are using magnetic data store for the most part of the century.
I'm planning to make a (commercial) device that would utilize hall effect sensors, but i'm wondering if there is some serious downside of using them, since so few devices use them.
The use case i'm considering:
Having input keys with a decent travel length, where can track their position with relatively low latency and at at least ~256hz update rate,
Alternative solution i could utilized but ruled out:
- Mechanical potenciométer - not the cheapest option, and will degrade with using, fairly quickly in this use case.
- Optical solutions - i'm not sure if i would be able to get it manufactured in a sealed fashion and with time dust and dirt would compromise it's operation, this applies to both encoder and the Adomax Flaretech (wooting) switches
- Force sensors - They are pretty expensive as i see, and would require fairly complicated mechanical setup
So after this options, Hall effect sensing looks like a very nice option.
TI DRV5053 looks ideal for the job, at $0.3 at 1ku it's price is acceptable. The magnets required would cost less than $0.1 each.
For the physical assembly a cherry mx style switch could be used, since the have an extruding shaft, the magnet could be mounted on the end of it.
They are the most resistant to any external effect, unless you put a very strong magnet next to it, but even that could be detected in software and the user could be warned that it wont work correctly in the current situation.
Adomax Flaretech sound nice, but they are not really time tested, they are not very well protected. These "switches" are basically just optical modulators, you need to have an LED and a light sensor on the pcb, the switch itself is really just a "mirror" that changes the amount of reflected light based on how much it is pressed.
Am i missing someting? Please let me know!