Rotary encoder instead of buttons

[robmil]

Hi

I have a signal switching circuit which is based solely on momentary push button and relay activation. I would like to convert part of this (volume up and down) to a rotary type. I'm not too up with rotary encoders etc. Is this a simple exercise converting up/down buttons to rotary encoder?

thanks

Rob

 

[justblair]

Hi

I have a signal switching circuit which is based solely on momentary push button and relay activation. I would like to convert part of this (volume up and down) to a rotary type. I'm not too up with rotary encoders etc. Is this a simple exercise converting up/down buttons to rotary encoder?

thanks

Rob

Hmmnn Simple is such a subjective term,

Rotary encoders must be decoded in order to make them work.

Try doing a search on gray code (a common type of encoder) to get an explanation of how it works.

You really need a processor to convert the movement of the rotary encoder to volume up and down commands. You could use a PIC or AVR controller, but this is going to take some programmming.

Maxim make a digital volume pot the MAX5440 which can take the signal direct from a rotary encoder however it only comes in a surface mount package. I have played with trying to get it to work but failed. I got fed up eventually. I have bought a pic programmer and eventually will get round to learning JAL properly in order to get the same result.

Alternatively there are a couple of people here who have programmed chips to do this. You could look through threads and ask nicely for some code. You would still need a programmer of some sort.

I an determined that eventually I will get one to work. But I dont see it as a venture that i will be able to complete in the short term.

Hope my experiance isn't too much of a downer on your idea. Rotary encoders are way cool. Digital pots have some big advantages over stereo wipers in terms of size and tracking between channels.

Push buttons are a bit easier. Maxim make a chip called the DS1802 which can be ordered in DIP and is easy to kmnock up into a design. It is limited by the voltage of your line in. Pedja Rogic has details on using this chip on his web site.

 

[MarkRehorst]

If you're up for learning a little programming, it is really easy to decode a rotary encoder- usually just a table look-up.

You could probably skip the programming and wire the whole thing using logic chips, but a uC would only require 1 chip, so wiring would be much simpler.

I_F

 

[robmil]

Thank you for your replys. It's exactly what I needed.
R

 

[ALBQ]

Check thread - Basic Stamp w/Rotary Encoder

Check this thread for circuit using a BasicStamp
ALBQ

http://www.diyaudio.com/forums/showthread.php?threadid=64373&perpage=25&pagenumber=1

 

[Chartal]

I think you need pulse switch.

Look this site, there are some information about theses switches.
Go to the bottom -->> An Alternative to a Rotary Encoder

 

[theAnonymous1]

I think you need pulse switch.

Look this site, there are some information about theses switches.
Go to the bottom -->> An Alternative to a Rotary Encoder

I've been looking for something like this, thank you.

Here is a link to one mouser carries for $4.95 ......

http://mouser.com/Search/ProductDetail.aspx?qs=qRWIMmAGXrXKRyi39HU/xQ==

 

[sansbury]

The AVR-based Arduino open-source microcontroller is another nice option.

I found it extremely easy to learn (as a software guy with a liberal arts degree) and because it goes right into your USB port you don't need to buy a programmer or anything to do your first project.

www.arduino.cc is the homepage.

 

[robmil]

Thanks for all the help. I think I may go for the pulse switch. I've attached a PDF of the control ciruit. It's only the volume I want on a rotary. The I/O drives a series of relays through several 4094s and 2 x ULN2003s. The preamp has a resistor ladder on it.

R

 

[robmil]

just found the alps pulse switch. It has 40 detents which is not enough unfortunately. Looks like the rotary encoder option is better for this application.

R

 

[peufeu]

Well, rotary encoders use gray code (ie a certain angle corresponds to a certain code), but you could use another type which has no reference (ie you can turn it several times) and just provide a direction+pulse signal :

Sample on rising edge of "pulse" signal :
if "direction" = 1 => it was turned clockwise
if "direction" = 0 => it was turned in the other direction

It is very easy to use with a controller.
However it has no memory (ie. you can-t put 0-10 marks on the dial since there is no "0"). But I like the feeling those provide, like the iPod wheel, sort of.

OOps, I see this has been mentioned.

I will use one of those in my next project :

http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=1114163;keywords=25L

 

[BrianDonegan]

just found the alps pulse switch. It has 40 detents which is not enough unfortunately. Looks like the rotary encoder option is better for this application.

I believe that's 40 detents per revolution, but spins freely like a rotary encoder.