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$18 Lot of 70 red modules at 5mW

Cyparagon

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Available at this link for $18 shipped. That's 25 cents per module, so why the f:)ck not? I'll try to let the pictures do most of the talking. Stock google image:





They arrived in about a week all in the same pink bag. Minor defects: 4 with a lead missing. Major defects: 1 with an open resistor and 1 LED'd instantly - I'll let you take a guess why:





Some measurements and observations:
Diameter: 6mm (6.5mm with PCB)
Length: 9.9mm (14.4mm with PCB)
Lead length: about 45mm
Material: brass
Beam diameter: ~2x3.5mm
Focus: adjustable
Operating current: 20-22mA at 3V
Driving method: 33Ω current-limiting resistor
Threshold voltage: 2.4-2.5V
Threshold current: 9-11mA
Case electrical potential: Positive
Lens: acrylic plano-convex Ø3.7mm FL:6mm transmission:~87%


Unit can be disassembled as such:





Beam shape is typical:





At 9 meters, dot typically looks something like this (due to spherical aberration and other lens imperfections):






Side note, the intensity gradient is less pronounced than the images portray. Some of the poorer ones (maybe 15%?) can look like this:






Since the focus is fixed, divergence will be a measure of how precisely the machine placed the lens. It didn't do too well. I only measured 35 of them, because it was getting boring. Measured at 9m:





The current varies <5% from module to module, and they all follow the same curve:






Here are the measured powers at exactly 3V:






And the wavelengths:






A scatter plot with more accurate values. Is there a correlation? No, not really.






Stress test up to 4.2V of three random units:






As you might expect, they don't get hot. They don't even get warm unless
you over-drive them. Here is one operating at 4V:






But what do you do with them? Well, here are a few ideas to get you started.





This printer is now a laser printer!





Yo dawg, I heard you like pointers, so we put a pointer on your pointer so you can point while you point.





Never miss your mark again!





Upgrade your transformer action figures with a laser gun (don't be fooled here, there's more than meets the eye)



So there you have it. There's no regulation, but for 25 cents you can't complain.
Bottom line: these are for pointing/aiming, and they'll do that just fine. There's no scam here, you really do get 70 modules (90-97% are functional) for $18.


Equipment used:
Coherent lasercheck power meter
Science-surplus spectrometer
HP 6116A precision DC power supply
Fluke 8010M 3.5 digit multimeter
Fluke 8810A 5.5 digit multimeter
Flir i7 thermal camera

Used $20 potato camera
 
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styropyro

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Great writeup, those look like a pretty good deal. I have a set of these coming in the mail currently and I'm looking forward to messing with them.
 

LaserCo

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Great post cyparagon! I have a pack of 60 of these I have not figured what to do with yet.
You say the focus is fixed, yours look just like mine and mine are adjustable, its not very
hard to get the lens head to unscrew past the point of where it is glued.
The listing that I purchased mine from said they were copper also! NOT True.

Did you ever test to see if the lens was glass or plastic? or its focal point?
 
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Gun

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Can I have the link for where you actually purchase the modules? :)
 

Pman

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Almost laughed out loud with the transformer:) +Rep just for that. Made my day so far
 

ped

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Cant rep you yet...Damn...I want a FLIR!
 

Cyparagon

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The link was the first word. I'll try to make it more obvious next time. I'll also check up more on the lenses later tonight.
 

lasersbee

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The link was the first word. I'll try to make it more obvious next time. I'll also check up more on the lenses later tonight.
Your Link only goes to a photo of the Laser...
Here's your Link data...
http://cloud3.lbox.me/images/384x384/201208/6mm-3v-5mw-laser-dot-diode-module-head-wl-red-650nm_imgqes1346397888144.jpg

Either way...
Nice detailed review... I love the graphs and barcharts.


Jerry
 
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Cyparagon

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Your Link only goes to a photo of the Laser...


I'll fix that in a second.

Update on the focus - it is indeed adjustable! The glue is even weak enough that you can loosen it with your fingers alone. It disassembles into these parts:



The lens is a plastic of some sort - I'll call it acrylic. It's a plano-convex type with a focal length of about 6mm. It is embedded in a cylinder (hard to see here) that acts as a mount. The entire acrylic piece is ~4.87mm in diameter and ~2.12mm in height, while the lens itself has a diameter of ~3.75mm. I measured transmission at about 87%. Adding this to post one...
 

Lazerbeak

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It's so small :) You actually were able to take it apart and measure that. That's awesome.

~ LB
 




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