Bulk 3V 5mW mini red lasers

I bought three (3) packets of 70pcs 5mW red lasers for $18 each on eBay, which comes to about $0.25 each laser. One of the 70pcs packs had 80pcs so I actually received 220 of these lasers for $54 shipped. This price makes them about the same price as LED finger lights in bulk quantities.

The lasers themselves are very small and come in a simple brass housing with lens and leads.



The dot grows to about 0.5" (~1.2cm) or so at about 20ft (6m), but is decent for short distances. It may depend on how the lens is situated in the short holder.



I picked out one of the lasers and ran some tests to see how it performed.

3V, 20mA, 7mW



4V, 40mA, 14-15mW



4.5V, 50mA, ~15mW, LEDed



I was actually able to push it to 4.5V for a little while, but the second time it it LEDed. It actually didn't entirely LED, and still puts out a decent dot suitable for playing with cats, but the output dropped dramatically.

Finally, I took the semi-burnt out laser and fitted it into a finger light. It took a little work, and a little bit of snipping, but it works pretty decently. I only used 2x of the 1.5V batteries and used the third battery to hold the wire in place. I also had to solder one of the leads to a thicker piece of wire so that the switch would work:

That's awesome Bionic Badger thank you for running tests, I have some similar diodes and I was wondering what kind of output these little diodes have. The finger light hack is veeeery cool

~ LB

That's pretty darn cool, thanks for the review.

This is indeed cool.
I also have a few similar small ones, and used them to build in various stuff,
Like a lighter, a pen and now trying to build 3 or 5 in a flashlight host, just for fun.

Ok guys, I hope this isn't thread-jacking, but Hak gave me a bunch of these and I have a project in mind. I want to attach them all to this array and get it working....thoughts?

Yes, do it.

The only question now, is how. Build thread coming.

scumbagatheist said:

The only question now, is how. Build thread coming.

Click to expand...

Nice... Desoldering time

Whoa! Those finger lights are sweet! I was debating on ordering some, now you have just clinched the deal for me.

now wire them all up pointed at the same spot until you can burn electrical tape. Then put it in a project box and you have a portable burning laser, ZOMG!

i have this. 100pcs 650nm 6mm 3V 5mW Laser Dot Diode Module Red Copper Head-in Diodes from Electronic Components & Supplies on Aliexpress.com | Alibaba Group

But need help for measurement.

distance at 1cm / (focused light 0.3 or 0.4mm on ruler) = ? mW
distance at 2cm / (focused light 0.3 or 0.4mm on ruler) = ? mW

1 cm or 5 meter target the has been the same milliwatts?



Kindly regards,
Thank you.

Just tried one at 5 v and 30 ma LPM says 7mw. This is the same unit only it's rated at 5v. What do you get for a dot at 3v? Just ran it up to 7v and 50ma and it's putting out 11mw, but went to 3mw with in 30 sec. At 3v and 10ma it runs 2mw. They look the same so I wonder if they are the same. Hope this helps. BTW Badgers' equipment is much better than mine.

I think the 3V and 5V units are the same, the only thing that changes is the resistor they use as current limiter.

undiffused 1 cm or 5 meter distance target the has been the same milliwatts?

3v 5mw laser>-------1cm------> ? = mw

3v 5mw laser>---------------------------------------5cm----------------------------------> ? = mw

Help.

Thank you.

It should be the same power. There will be small losses because dust in the air will absorb some photons, but this is negligible.

I bought some of those, and a year later they are still useless, LOL.

I get caught up in the " but there so cheap " way of thinking.

I have 1000's of resistors on tape strips and bags of dim leds that I know I will never use, but they were so cheap. LOL