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Can someone suggest a source for rotary mirrors? I'm looking for something along the lines of the ones in the image below, but I'd be interested in any alternatives as well. (I'm building a continuous laser harp, so the basic idea is I need to sweep an arc of about 45 to 60 degrees, or so.)

rotary mirrors

From what I understand these are fairly common in some barcode scanners and laser printers, so I'm open to salvaging them if there isn't a good place to buy them independently, though I'm not entirely sure what I should be looking for (in terms of what kinds of barcode scanners / what parts of the laser printer).

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closed as off-topic by Ricardo, Daniel Grillo, Scott Seidman, pjc50, Dave Tweed Jan 27 '15 at 18:06

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  • \$\begingroup\$ If you are looking for lists of parts your question does not fit here, if you are looking for guidance on how to find a part like this and would be happy with just a guide on how to go about finding such a part as far as a guide this does fit. Which do you happen to be looking for? \$\endgroup\$ – Kortuk Dec 26 '12 at 21:21
  • \$\begingroup\$ I'm looking for guidance on how to find such a part. I'm not even sure I'm looking for the part by the right name to be honest. \$\endgroup\$ – hexist Dec 26 '12 at 21:22
  • \$\begingroup\$ I have searched quite a bit for this part, all the usual places (digikey, mouser, thorlabs, and lots of google), but either I'm not searching for it by the right names, or I'm not looking in the right places. \$\endgroup\$ – hexist Dec 26 '12 at 21:25
  • \$\begingroup\$ That is how it read to me, thought I would verify for the crowd. \$\endgroup\$ – Kortuk Dec 26 '12 at 21:27
  • \$\begingroup\$ All (most?) LASER barcode scanners have these mirrors. CMOS/CCD 'camera' scanners don't, neither do 'wands' of course. - Basically, you only need a mirror drum of appropriate size; any small electric motor should then be usable to give it the 'spin'. \$\endgroup\$ – JimmyB Dec 26 '12 at 22:10
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The items you've posted are all complicated, specialized integrated assemblies. They're also very purpose specific.

As such, I can't think of many places you could just buy them as-is, independently of the device they're intended to work in.

Anyways, I do know that most laser printers to indeed use such a device, though I'm ~90% sure that the devices in the picture from the OP are all from bar-code scanners.

Basically, in a laser printer, they're used to sweep a modulated laser across the photosensitive, electrostatically-charged drum. The charge on the drum is affected by the light striking it, and then becomes patterned, affecting how toner adheres to it in the next step.
Anyways, in such a situation, the laser is only swept in a line, so the aspect-ratio of the mirror is small, so they're typically very short.

In the mirror assemblies in the question, the mirror drums are very tall. Since the height is not needed in a laser printer, they're probably from a bar-code scanner, that needs to sweep the laser in an x-y range.


Anyways, short of a few OKI printers (which are billed as a "LED printer" anyways), anything sold as a laser printer should have some sort of rotating mirror apparatus inside it, though how much luck you'll have making it work outside of the printer itself may vary.


Personally, I would check places like All-Electronics or ebay, if you can't track down some old laser printers locally.

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  • \$\begingroup\$ I concur with Fake Name. O.P is looking for a specialty item. It will be hard to find this subassembly as a separate OEM unit. The only thing that comes close are optical galvanometers (slang term "galvo") like these. But, I bet that an optics galvo alone would cost more than a barcode scanner [edit: or a small laser printer]. \$\endgroup\$ – Nick Alexeev Dec 26 '12 at 22:15
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    \$\begingroup\$ It's also worth noting that not all barcode scanners have spinning mirrors in them. The kind of mirror in the OP comes from the barcode scanners that mount into a countertop, not the hand-held variety. \$\endgroup\$ – Connor Wolf Dec 26 '12 at 22:17
  • \$\begingroup\$ Hand-held scanners have an oscillating mirror. (I have a photo, which I can post.) \$\endgroup\$ – Nick Alexeev Dec 26 '12 at 22:19
  • \$\begingroup\$ @NickAlexeev - Only some of them. A lot of them these days just use a bunch of LEDs, and a CCD (I have a few of this variety). \$\endgroup\$ – Connor Wolf Dec 26 '12 at 22:22
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BUILD, NOT BUY

Why not make a crude one using a bunch of tiny mirrors attached around the rim of a wood or plastic disk w/DC motor? If too crude, learn from mistakes and make a better one on second attempt. Perhaps make a 3D-printed base which is designed for whatever mirrors you've found. (PS, they're called 'octagons' in the barcode biz, even if they're not 8-sided.)

Me, I'd try one of those piezo flapper-fan thingies and stick a tiny front-surface mirror on the oscillating blade.

I've seen very tiny f.s. mirrors at Surplus Shed, the online optics junk shop. That, or slice up an old CDROM.

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  • \$\begingroup\$ Interesting thoughts! I may very well try that if I can't find a cheap scanner to rip apart that has one of these. My primary concern with constructing one my self is I doubt my ability to make one that is balanced well enough and where the mirrors are flat enough, but as you point out, if the first N suck, just make sure N+1 sucks less and eventually I'll get there :). Thanks for the Surplus Shed link, I'll be keeping an eye out there for goodies! \$\endgroup\$ – hexist Dec 27 '12 at 0:54
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A few things you could look for in shopping for surplus parts either to repurpose or build your own:

First Surface Mirror: These mirrors are coated on the front and are typically used in optics and laser applications. They're available in "experimental," "commercial," and higher grades. Unless you need specific wavelength specifications, go for the experimental or commercial grades (but even those can be costly). Sources: Edmund Optics, Anchor Optics

Galvanometer-driven X-Y Scanner Pair aka "X-Y Scanner Pair" or simply "galvos" or "scanners" in the laser entertainment industry: This is a device commonly used in laser entertainment. It consists of first-surface mirrors mounted on two galvanometers which are used to control the angle of a reflected beam on an X and Y axis. You can find these for sale on eBay from time to time. The price ranges from $50 to many hundreds of dollars depending on the quality and speed. Depending on your application, you may be interested in something like this instead of mirrors on a rotating cylinder.

Stepper motor: A motor that can be controlled in fine increments or "steps" for precision speed control. This appears to be what the mirrors in your picture are mounted to. They come in several types including unipolar and bipolar, and vary in the number of steps.

You'll have to check various surplus outlets for these. I found a list of surplus optics and equipment at http://amasci.com/surplus/surpopt.html.

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