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Pure mechanical rotary encoder switch needed.

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Imagewerx

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I know all about the normal type of mechanical and optical rotary encoders that need a processor to work out what direction it's being turned and provide a pulsed output using quadrature or Gray code.
I'm trying to find something simpler than this that involves just switches and no other electronics.Maybe some sort of sprag clutch or one way bearing that lets only one toothed wheel turn when you turn it clockwise and only a second one when you turn it anti clockwise,these toothed wheels would operate normally open microswitches positioned around the edges of each of the one way wheels.Oh and of course it has to turn continuously without any stops.
There has to be something like this say in old fashioned radios (maybe aircraft) where the frequency selection dial(s) worked in this way,before their direction of rotation could be detected electronically?
 
In radios the direction of rotation isn't important, only where the dial is. There might be gearing, so that there would be several turns to cover the range, but there is no reason for direction detection.

There are mechanical direction detection devices, or items that deliberately work one way and not the other. Examples include:-
Friction ratchets, where movement one way is easy, as the ratchet turns, but in the other the ratchet locks and a friction element has to be overcome.
Reversing devices on small synchronous motors used in clocks, to stop them going backwards.
Mechanical car speedometers, where eddy-current drag pulls against a spring, and the zero stop prevents it moving when going backwards.
 
You can use a single toothed cog acting on a paddle that activates two back-to-back (or front-to-front, as the case may be) microswitches.
 
In radios the direction of rotation isn't important, only where the dial is. There might be gearing, so that there would be several turns to cover the range, but there is no reason for direction detection.

I think you think I'm referring to HF radios that have continuously variable tuning down to fractions of a kHz,I actually meant VHF radios that are tuned to specific frequencies with a specific channel spacing.I think probably 50 or even 100 kHz back when they were purely mechanical switches,8.33 kHz now they're running out of space.

You can use a single toothed cog acting on a paddle that activates two back-to-back (or front-to-front, as the case may be) microswitches.

Oddly enough I came across this patent application drawing a bit later that works in exactly the way you suggest......



This sort of thing would be perfect if anyone ever actually made this,if not it wouldn't be all that difficult to make at a DIY level.But although I'm sure I've seen this type of switch used for different purposes over the years,I can only find one that might be suitable on the whole internet............

**broken link removed**

And I can't find a supplier here in the UK unless I buy a 1000 or more of them.
 
Oddly enough I came across this patent application drawing a bit later that works in exactly the way you suggest......
I hope the patent is not for the encoder itself; it's a little obvious.
although I'm sure I've seen this type of switch used for different purposes over the years,I can only find one that might be suitable on the whole internet............
They're also used in some CD-ROM drives to detect tray in/out position.
 
I have seen them, well one, I think it was ex mil equipment.
Turn the shaft one way and one v4 type microswitch was pulsed on/off, and turned the other way another v4 pulsed on/off.
This would have been quite old, that kind of thing didnt find its way much into commercial products probably due to the expense.
You might find something in ebay.
 
I have seen them, well one, I think it was ex mil equipment.
Turn the shaft one way and one v4 type microswitch was pulsed on/off, and turned the other way another v4 pulsed on/off.
This would have been quite old, that kind of thing didnt find its way much into commercial products probably due to the expense.
You might find something in ebay.
That's about what I'm looking for.It's difficult after a VERY busy day at work when my brain is fried when trying to think of search terms to come up with anything original.Was off today so gave it another go Googling every type of switch under the sun and came up with 'rotary pulse switch' that was anywhere close to what I'm after.Of course Alps will make ANY type of switch,including one like this.....

https://www.alps.com/prod/info/E/HTML/Switch/Rotary/SRBM/SRBM1L1400.html

But if I interpret this correctly this has end stops so won't do more than a single revolution and can only make 20 pulses,which is no good for me as I need at least 100 in both directions.

Alps to the rescue again with these..........

https://www.alps.com/prod/info/E/HTML/Switch/Detector/SSCM/SSCM_list.html

All I need to do is to find (or make) a suitable toothed wheel and it'll do everything I need it to.
 
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I've seen those,but are they not just two way with off at one end and on at the other? I need three way with centre off and on when it goes left and right.
Some are, some aren't. The one in my hand atm is a bidirectional (2-switch) type.

You could also use leaf switches. I didn't see any appropriate ones in google images, but they're very easy to make: just get a thin metal shim as your paddle, and place a conductor either side of it.
 
The switch I mentioned came with some equipment, probably aircraft.
I was thinking fabricate something, you could use a hall effect sensor with a disc with holes drilled into it, fabricate a little spring steel arm that enagages with said holes to act as a detent, it'd need to be a fair size though with 100 holes.
I have some shaft encoders with quarature outputs, they'd be just the ticket using a pot as the bearings, bit I'm getting to complex.
 
Some are, some aren't. The one in my hand atm is a bidirectional (2-switch) type.

You could also use leaf switches. I didn't see any appropriate ones in google images, but they're very easy to make: just get a thin metal shim as your paddle, and place a conductor either side of it.
I was thinking of DIYing the switch anyway as all the ready made open microswitches are normally open/normally closed and not centre off as I need.

The switch I mentioned came with some equipment, probably aircraft.
I was thinking fabricate something, you could use a hall effect sensor with a disc with holes drilled into it, fabricate a little spring steel arm that enagages with said holes to act as a detent, it'd need to be a fair size though with 100 holes.
I have some shaft encoders with quarature outputs, they'd be just the ticket using a pot as the bearings, bit I'm getting to complex.

Thanks for the suggestion but that's getting a bit complicated,I want to keep it simple on purpose.Once I start using Hall effect devices,I might as well go back to Gray code or Quadrature which I have here anyway.
I should have said that the 100 pulses don't have to be in the same revolution,in fact it's better that they aren't as it'll make it a bit too sensitive,I reckon on about 20 or 25 per revolution would be about right.
 
How about 20 mini neo magnets and a reed switch, you might be able to get a reed switch to only work with a north or south pole if you bias it with another magent.
 
How about 20 mini neo magnets and a reed switch, you might be able to get a reed switch to only work with a north or south pole if you bias it with another magent.
I had thought briefly about reed switches,but I don't see how this method would know which way it's being turned,which is what I need as well as the pulses?
 
Yes you'd need 2 pulse discs and a directional clutch, the sort of thing in a ratchet screwdriver.
 
Yes you'd need 2 pulse discs and a directional clutch, the sort of thing in a ratchet screwdriver.
An interesting idea,but a bit too mechanical for what I'm trying to do.I've found some of these in small quantities so have ordered some and will go from here.....

**broken link removed**

But....a proper pulse switch would still be better if anyone knows of one.So a switch that generates it's own directional pulses without the need for any sort of electronics.
 
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