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What can I use as a scroll wheel?

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buurin

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I want an input device very similar to a mouse's scroll wheel / thumbwheel on a mobile device.

I am not entirely sure what the technical name of such a device would be.

I simply want to use it to be able to scroll throgh numbers 0-9 on a 7-segment display.

Direction is important (i.e I should be able to determine in which direction the device is being scrolled)

Also I'd need to be able to order it in small quantities.

thanks
 
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Why not use a scroll wheel?? Is it required to actually rotate? A simple spining wheel with a small lever inside to touch a switch for up or down.
 
I dont totally understand your wheel/lever idea...

Are scroll wheels easy to interface? I've never dealt with one, what kind of output can I expect (i.e. analog, digital, encoded, etc...?)
 
I've attached a lovely MSPaint example =) I've seen many mice that use this as their scroll mouse function, some people like the tactile feedback a little more than an actual spinning wheel, little easier to implement as well than more complex optical or encoder wheels.
 

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I am not entirely sure what the technical name of such a device would be.
You are looking for a quadrature encoder. But Sceadwian's idea is easier to implement unless you want the wheel to be able to rotate fully. Then a quadrature encoder salvaged from an old mouse with balls would be ideal.
 
If you don't mind the excessive price...

Dinky 1cm trackball with mechanical contacts:
https://www.mouser.com/search/ProductDetail.aspx?R=TBWB2A00virtualkey61170000virtualkey611-TBWB2A00

I also have seen/bought a small wheel type switches that mount with the wheel flat against the PC board - they're meant to stick out the side of a handheld widget for use as a scroll mechanism. Search the digikey site for "edge encoder"

These things usually use gray-codes like your typical encoder, hence the names.

Also, I think electronics goldmine still has some PC compatible 1cm trackballs (that are probably 2 decades old at this point) in their catalog somewhere. Cheap if you're willing to debug the protocol - or if directly access the optical sensors.
 
I've read up on encoders now and I dont think I want to deal with trying to decode its output. I'm not terribly concerned with aceleration, etc....

Maybe I should just use a pot? Seems like it'd be quite a bit easier and for the most part just as easy for the user.

All I am doing is selecting a number on a 7 segment display.

Unless someone can convince me otherwise I think I am going with the pot. Thanks for your help. Knowing about the encoders will certainly be useful in the future.

Thanks Again
B
 
Well, it really just depends on what you want the device to do, and how you want it to 'feel'. A rotary encoder is a great input device, it can be decoded by simple logic to give pulses for rotation, and a logic output for direction. If you simply wish for the device to output 'up' and 'down', then sceadwian's idea seems doable. Or you could try here:

**broken link removed**

Its SMT, and quite small, but its pretty much like the ones you get on the side of flashy mobile phones. Ie: simple a up/down switch, not strictly an 'encoder' at all. I believe farnell have a large number of different scroll wheels, but they might not be that cheap. I've used many different types, including ripping up an old ball mouse and using its encoder whells attached to pot shafts, for a smooth feel and excellent resolution (200 cycles per revolution).

Hope this helps.

Blueteeth
 
A mechanical rotary encoder switch might be perfect with a wheel instead of a knob. Digikey part # GH3076-ND or Grayhill # 26ASD22-01-1-AJS is a 16 position BCD output from 0 to 15. You could put a stop on it at 9.
 
No, just twinkly red eyes but no balls and thus no shaft encoders. :D
 
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