Author Topic: Miniature optical limit switches  (Read 526 times)

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Offline ZbigTopic starter

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Miniature optical limit switches
« on: December 05, 2022, 10:26:24 pm »
During the disassembly of various gear (like laser printers, etc.) I learned of the existence of an element that I'm pretty sure is a transmissive (slot) optocoupler with a tiny integrated, spring loaded lever that interrupts the light path. The whole thing just a five or so millimeters across. Imagine something like a classic tact switch but with a tiny plastic "tooth" poking from its side instead of a button on the top. The "tooth"/lever physical resistance is very light, smooth with no discernible actuation point which makes me think those are actually optical.

The thing is, I want something like that for my project but have had no luck finding anything like that. Does anybody know how to search for such a thing?
 

Offline jwet

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Re: Miniature optical limit switches
« Reply #1 on: December 06, 2022, 12:53:04 am »
I've never seen an off the shelf one and I've seen a lot of opto type gear.  The usual solution is to use an optical slot device and make the flag/gate piece yourself.  This is a lot easier with 3 d printing.  Make a cam/flag gadget armature, use some small drill rod or a small shaft, make a yoke (c-shape) with your 3d printer and you're done.  Take care that your plastic flag material is opaque to IR light, some plastics look almost back but IR will go right trough them.
 
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Online tooki

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Re: Miniature optical limit switches
« Reply #2 on: December 06, 2022, 02:39:27 am »
During the disassembly of various gear (like laser printers, etc.) I learned of the existence of an element that I'm pretty sure is a transmissive (slot) optocoupler with a tiny integrated, spring loaded lever that interrupts the light path. The whole thing just a five or so millimeters across. Imagine something like a classic tact switch but with a tiny plastic "tooth" poking from its side instead of a button on the top. The "tooth"/lever physical resistance is very light, smooth with no discernible actuation point which makes me think those are actually optical.

The thing is, I want something like that for my project but have had no luck finding anything like that. Does anybody know how to search for such a thing?
Nope, not optical. Just really light springs. They’re sold as limit switches or “detector” switches. For example, TE Alcoswitch JJ series, or Omron D3S* series.

Here’s some on Digi-Key: https://www.digikey.ch/short/qr94bdf0
« Last Edit: December 06, 2022, 02:40:59 am by tooki »
 
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Offline ZbigTopic starter

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Re: Miniature optical limit switches
« Reply #3 on: December 06, 2022, 10:34:31 am »
Thanks guys, that would make sense. Would be trivial to figure this out myself if only I had one on hand instead of just having seen few of those in passing. Actually, 3D printing the "interruptor" part was my original idea but then I figured why deal with small details and tight-ish tolerances if there's something ready-made available. Now, that I'm back to it being my only option, this is totally fine. Thanks again!

Cheers,
Zbig
 

Online Psi

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Re: Miniature optical limit switches
« Reply #4 on: December 06, 2022, 10:59:48 am »
FYI, TACLEX make cheaper detect switches that are often pin compatible with Panasonic/omron versions

http://www.taclex.com/en/Product-3-15.html

You can usually find them on aliexpress if you search for a taclex part number.
Greek letter 'Psi' (not Pounds per Square Inch)
 
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