[sdiy] rotary encoder?

[Tom Wiltshire]

On 8 Jan 2009, at 06:31, Matthew Smith wrote:

> Quoth Aaron Lanterman at 2009-01-08 16:22...
>> One of my senior design teams had a whole bank of 2-bit Grey code   
>> rotary encoders; they used a microcontroller on each individual   
>> encoder, since the microcontrollers were something rediculously  
>> cheap  like 60 cents each.
>
> And that's pretty much what (and why) I'm doing this with my control
> surface.  I started out trying to use a single microcontroller but
> decided that this was silly as they are pretty well the cheapest  
> parts!
>
> A single microcontroller that has internal pull-up resistors on the  
> port
> pins and an internal RC clock can monitor 4 x 2 bit encoders on a  
> single
> port.  Throw a couple of extra port pins into the equation and you can
> scan them as a matrix.
>
> If an encoder value changes, you store the new value, throw an  
> interrupt
> at the main microcontroller, then have the new data read out over  
> SPI or
> somesuch.
>
> After figuring this out, I have decided to go for a more modular
> approach, using several cheap interconnected microcontrollers for  
> all my
> projects.  This also has the benefit that a lot of those tricky  
> hardware
> problems can be solved in software.  (Even better if you're doing the
> hardware design and someone else is doing the coding ;-))

I've wondered about something like this too, after having seen the  
nice "virtual pots" on the Nord Lead. The thought was that you could  
have a ring of LEDs and a single encoder connected to a cheap uP,  
which would provide LED drive and read the encoder. You could then  
just treat the whole shebang like a single part and set or read  
values via SPI (or whatever comms takes your fancy).

T.