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Mini update: power hungry lasers

A project log for Laser Galvo Clock

Clock projected onto the wall with cheap laser galvos

Alan GreenAlan Green 07/06/2019 at 01:374 Comments

So far, my experiments have used the cat's battery powered laser pointer. Today, I disassembled a few laser pointers and powered laser modules directly from my bench power supply. 

The green laser module was the brightest and looked the best. Also, I know it will be visible in the day time. According to the sticker that was on it, it is a "class III"  and "<5mW", which I believe makes it a class 3R laser, which I'm happy with from a safety point of view.

However, it also draws between 250mA and 350mA, which is much more load than I want to put on the RPi's supply, especially since that load will be switched rapidly and repeatedly. 

So, instead of using the output of the 3.3V LDO to supply the laser, I'll use a 12V wall adapter, along with an eBay buck converter module.

Discussions

manta103g wrote 07/10/2019 at 14:08 point

Is Hackaday really made of one-man projects ?

"Your application is pending

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Stefan Krüger wrote 07/08/2019 at 20:28 point

please keep in mind that cheap green lasers can emit a bunch of infrared!

(they missing a good ir-blocking filter in the output)

some more info in this video and link

https://www.youtube.com/watch?v=iR1Ku5dnbH8

https://ws680.nist.gov/publication/get_pdf.cfm?pub_id=906138

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Alan Green wrote 07/08/2019 at 21:31 point

That's a really good point, thank you.

I particularly enjoyed reading the experimental set up described in the PDF from NIST. I suppose they used paper cups to emphasize how cheap their rig was :)

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manta103g wrote 07/06/2019 at 17:11 point

I have a number of green lasers and was offered a blue laser, but the price is still prohibitive.

Not sure about the laser classes, since all lasers come from China.

Tested laser distance meter (40 meters range red laser) and works fine indoor but fails to detect mirrored laser beam in outdoor, so not fit for my lidar laser car radar project, operated mostly in outdoor environments.

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