HiLetgo 10pcs 5V 650nm 5mW Red Dot Laser Head Red Laser Diode Laser Tube with Leads Head Outer Diameter 6mm

These little guys are pretty decent laser diodes! They’re super bright and fairly inexpensive. I used three in a project for an ECE class at UCON and am very happy with the results. While I think they have a resistor built into the driver I’m driving them at about 4.5V with a 100Ω resistor in series with the device. The small package was easy to integrate into my project enclosure. I noticed that these are focusable. You can twist the collar near the output side to focus the dot. Yes, laser diodes don’t have a perfectly round dot, but when focused properly, you really can’t tell by eye over short distances. At 100 meters, you will definitely notice dispersion and distortion, but I very much expected that. All in all, these met my expectations, and I’m happy with how things turned out. They work great. Note: I only have a few hours of use on my project, so I can’t say how long they will last, but like most things electrical, you can pass a low amount of current through them for a long time or a very large amount of current through them for a very short time. If run at spec, I assume they will last just fine. BTW, I got an A on my laser transmitter project. W!

This laser diode is perfect for my application which is a laser sight for a Bug-A-Salt unit. However, it pulls 50% more current than the published specifications. The one I tested pulls about 29 mA at 5V instead of 20. I plan to run it from 3 AA batteries in series so I expect it to pull about 25 mA which is fine. The dot size is pretty large but I don't expect miracles for the price, so I'm pretty happy with this product.

Amazing Laser Diodes. They all work like they should, and are easy to hook power up to. I use them mainly for fun expirements and stuff, but I made a little laser with them to. A bench power supply is very useful to have when using laser diodes like these. I dont have a laser tester, but I think these are probably close to 5mw. they are very nice and small and fit perfectly into astandard pen if you want to make a simple laser pointer pen. They seem to keep working for a while as long as you put the recommended power to them. Anything up to 5V works great, and even up to 8V makes it brighter, but they will usually fry after a while. I found out that 8V is when they get brightest and stay bright. anything over that will usually fry pretty quickly and get very dim. Also at over 5V a heat sink would be great.

The price for this 10-piece set was fantastic, and the delivery was faster than I expected. I have not powered them all on yet, but I took a random sampling of 4 and they looked bright and uniform. The spot-size looked uniform in an 'across the room' test, so the laser quality seems fine. For my application, the "precision" of the aiming is done by hand, so I also wasn't too concerned if they are/not perfect in that regard. The lead wires would be a concern in an environment that experience much of any vibration, but that too was not a worry for my need, so I think they will be more than sufficiently durable. The size, of 5 mm diameter was easy to work with, and since I was 3D printing the holder, I could adapt to most anything. I also appreciated the option of either 3.3V or 5V, the latter of which was right for this project, but I also work with 3.3V designs, so I'll keep that in mind for the future.

Limited focal length for up close work as spotter (too long). Reducing the power with around 390 ohms makes a small (not overpowering) red dot.

Good for my small projects etc.

These are Ok red lasers, but not for mission-critical projects. Some just die without warning, and you will need to replace them. I had a project with 32 lasers, two died before I installed them and 3rd one died later. But they are cheap and when they work - they work.

I am using it to align an optical system. It doesn’t need to be perfect so these actually worked out great. They're easy to use, just cool them up and it works. The lens turns to focus the beam. They can be run off 2 AAs, I added a switch in series to make it easier. Its less than the ideal voltage but dimmer is better in my application. I think they're a great value and worth picking up.