I just bought a package of 100 laser diodes on eBay:


enter image description here

My first question is: Will they need a driver? Can't I just hook two of them up in series to a 9V battery, and be done?

Secondly, I plan to attach them all to a Halloween costume and fire them all at the same time. My initial thought was that I could solder two and two in series, and then create one giant 50-in-parallel circuit of these sets of two laser diodes. Then I was hoping to run the caboodle from the aforementioned 9V battery. Is this a proper way of doing this?

  • \$\begingroup\$ Just let us know where, so we won't be there when you fire up the 100 5mW lasers all at once. Sounds annoying \$\endgroup\$ – Scott Seidman Sep 12 '13 at 15:34
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    \$\begingroup\$ Since you have 100 of those LASER modules, open up one of them and check if there is some circuitry inside: I've ordered similar looking modules from eBay (not the same ones), and they included constant current drivers inside. My modules consume a fixed current for supply voltages from 3 Volts through to 6 Volts, and they burn out at around 7 Volts, even if there is a brief spike. There is no surety that yours are the same, but surely you can sacrifice one to find out. \$\endgroup\$ – Anindo Ghosh Sep 12 '13 at 15:46
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    \$\begingroup\$ Unless you have a fog machine in your hat, wouldn't the effect be limited to a few tiny red dots on nearby objects and the sound of people complaining about lasers shining into their children's eyes? \$\endgroup\$ – RedGrittyBrick Sep 12 '13 at 16:10
  • \$\begingroup\$ Thanks for the feedback. Yep, I'm not expecting a massive laser boost that will blast people out of their seats. But I will have access to smoke/fog, and hopefully I can allign all the cylinders in somewhat the same direction. Interesting to know that they work similar to a common LEDs, which I have experience with. Thus a 9V DC battery will probably be able to handle all those lasers for short periods of time (bursts), plus a resistor to make sure the lasers don't get too much power when the battery drains. \$\endgroup\$ – Pedery Sep 12 '13 at 17:38
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    \$\begingroup\$ I Inlined the image from your auction, since it will eventually go away when ebay deletes old auctions in a few months. \$\endgroup\$ – Connor Wolf Sep 13 '13 at 5:10

Unforrunately, no -- not if you want them to work correctly.

Laser diodes are somewhat similar to light emitting diodes (technically they are....) in that they have a particular diode I-V curve.

If anything, you would at least want to use a LED driver if not a constant current source. In that case you could wire a few in series.

Without a datasheet for your lasers, design is going to be a bit more seat-of-the-pants.

I recommend http://www.linear.com/product/LT3598 as a laser driver. It will require circuit design, soldering, and more parts I'm afraid. Still if you work hard it will make a great costume @ the end of October!

  • \$\begingroup\$ For clarity, a single 9 volt battery will not be able to drive all of these lasers. It doesn't have enough available power. \$\endgroup\$ – HL-SDK Sep 12 '13 at 15:23
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    \$\begingroup\$ A 9V battery should be OK - I think it's a PP3 you would have problems with. \$\endgroup\$ – RedGrittyBrick Sep 12 '13 at 16:13
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    \$\begingroup\$ That battery would work quite well :P \$\endgroup\$ – HL-SDK Sep 12 '13 at 16:26
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    \$\begingroup\$ I wired up all the lasers (it ended up being 72 in total) and connected them to a 9V battery. The whole thing worked flawlessly the entire evening (in bursts), without problems. Some of the other guests wanted to play with the cannon, and held the beam for more than 30 seconds. Technically this would be the same as powering a single laser for 36 minutes straight, but the battery showed no visible signs of drain. So I guess it's a success :) \$\endgroup\$ – Pedery Nov 3 '13 at 3:27
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    \$\begingroup\$ @Pedery check out what I found on the net! behance.net/gallery/200-LDs-Stage-Suit/493017 \$\endgroup\$ – HL-SDK Dec 20 '13 at 14:16

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