[sdiy] rotary encoder?

[Matthew Smith]

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 ;-))

Cheers

M

-- 
Matthew Smith
Smiffytech - Technology Consulting & Web Application Development
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