[sdiy] Question how to improve rotary encoder feel

[Ben Stuyts]

Speaking of Hall sensors reminded me of a visit of a local rep for AMS a while ago. He showed me a demo board of one of their rotary hall effect sensors. I think this was the sensor:

http://ams.com/eng/Products/Magnetic-Position-Sensors/Angle-Position-On-Axis/AS5045

It generates a 12 bit position (4096 steps/rev). Cost is €6 - €10 depending on qty. And this is the (expensive) demo board:

http://ams.com/eng/Support/Demoboards/Magnetic-Position-Sensors/Angle-Position-On-Axis/AS5045-Demo-Kit

They have a whole range of Hall sensors. Some of them also measure the strength of the magnetic field, so you could also implement a push button function.

Ben

> On 10 Jun 2017, at 07:22, Ben Bradley <ben.pi.bradley at gmail.com> wrote:
> 
> I'm trying to send this a second or third time, my last attempt made
> it to the list but may have looked like an empty post.
> 
> I've thought about this for a while. The readily available/cheap
> encoders give 12 to 24 pulses (or rest positions - they generally go
> through the whole 4-transistion quadrature sequence for each position)
> per rotation, so take many turns to set a value with reasonable (128
> or 256 position) resolution. I noticed in the late 90s the HP and Tek
> equipment had nice high-resolution optical encoders, butsuch encoders
> were $30 range, and still are. They're good and "affordable" if you're
> going to use one incremental encoder that is switched between all
> functions:
> 
> https://www.digikey.com/product-detail/en/bourns-inc/ENS1J-B28-L00256L/ENS1J-B28-L00256L-ND/1089392
> 
> I've had the idea of using two analog hall-effect sensors mounted ad
> right angles to detect the rotation of a magnet on the end of a shaft.
> They'll give a sine-and-cosine output of shaft position that you can
> run into the DAC of a microcontroller and use an arc-tangent function
> to get the shaft angle. With a little multiplexing, a single
> controller can read many shaft positions simultaneously (okay, fast
> enough to appear simultaneous). I was hoping I was the first to come
> up with the idea, but I saw it mentioned in the SDIY archives maybe
> six years ago.
> 
> I've got a few DRV5053 from TI, they're cheap enough at a dollar each.
> and about $0.50 for higher quantities. There are several models with
> different suffixes indicating different magnetic sensitivities:
> https://www.digikey.com/product-detail/en/texas-instruments/DRV5053RAQLPGMQ1/296-40066-1-ND/5177943
> They're available in SMT but to use them this way you'd have to mount
> one on each of two PCBs, and set the PCBs at a 90 degree angle to
> sense the field.
> 
> I saw this video a few months ago, he says these are the only two
> prototypes of this synth. I think this is a great interface, it's the
> ultimate as far as any ideas I have. Each function has its own knob,
> and the horizontal LED bar (that goes across the whole front panel)
> shows the value of the control when you touch the control, and varies
> as you turn the control. I wonder of each of those controls is one of
> those expensive optical encoders:
> 
> https://www.youtube.com/watch?v=xiV7lzYuM8I
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