Rotary Clicker Input Gadget Type Thing

[sjohnr]

The Bosch ovens in Europe used to have a knob to turn that set the desired temperature. Their would be about 10 or 12 clicks per rotation. But the neat thing was that the electronics would increase the rate of change of the desired temperature according to how fast those clicks were coming in. So if you turned the dial fast, each click would correspond to say, a 10 degree jump, or even higher. But as the click rate fell, each click would cause a 1 degree change in set temperature. Man, it was really neat. Now the cleverness was in the electronics, and the knob, complete with clicker, must have been a fairly simple device.

I have stumbled into an application where this exact arrangement would work really well. The problem is, I can't find any vendor who sells the rotary switch, which is what it really is when you get down to it. I imagine the switch would have a single common with a contact each for clockwise and anticlockwise rotation. A dozen indents or cams internally would mechanically fire the contact as the thing was rotated. Does this make sense? I am on the point of building my own (I'm getting frustrated) but I'm putting the question here before launching myself into that. Does anybody know of such a switch?

Thanks in advance, and apologies for being long winded.

 

[MacGyverS2000]

I don't have a vendor or part number offhand, but look for optical encoder switches with multiple detents as that was the most likely type. The output is a bi-phase signal that shows direction.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[waross]

If you are going to build your own, use two cams, offset one-half a tooth or notch. Your high points and low points should be equal duration.
This way, with one direction of rotation, "A" will always be high aleady when "B" goes high. When you reverse rotation, "B" will be high before "A" goes high.
It will probably be a lot easier and cheaper to by an optical encoder that basically will do the same thing.
respectfully

 

[sjohnr]

Thanks for your replies on this.

Optical was the part I was missing. I've got some suitable part numbers now.

The offset cam idea is something I need to remember. But as you suggest waross, the path of least resistance is just to buy the device.

Thanks again.

 

[Skogsgurra]

It may be one of these you have seen. I have used them for same application as you mention. They have 24 clicks/rotation and are quite good. Cost is around 2 USD.

http://www.elfa.se/pdf/35/03584745.pdf

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[itsmoked]

Digikey has 35 different items that fit your description including the detent.

Go to Digikey.com

1) Keyword search for "encoder switches"

2) Under the categories that comes up under 'switches' select "Encoders"

3)In the first category 'Detent' select "YES".

Then name your poison. Might base it on price - look at them all.

Or base it on reliability - pick capacitive or optical.


Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[VEBill]

Some cheap radios (like the HTX-100) have all-mechanical (not optical) rotary switches for frequency selection. The switch has the two P&Q outputs so that direction can be determined.

But optical would be better in almost every way.

 

[zeitghost]

And I bet the magic step rate increase/decrease function is done in software...

 

[geekEE]

Circuit Cellar Ink had an article on using rotary encoders a few years back.

http://www.circuitcellar.com/library/print/0303/millier152/index.htm

A Google search should turn up more stuff.

 

[peebee]

Sounds like a mouse wheel. Or the paddle controller off my old Atari 2600.