Best diode lasers according to redditors

Hey! I'm a chemistry grad student, and my group does this demo as part of a science outreach program we run. Here's how we do it:

We use orange highlighter for the right solution, which works quite well. You just dissolve an orange highlighter cartridge in some water.

The center one is just store-bought tonic water, though you could try some other colorless fluorescent compounds like POPOP or anthracene (the tonic water is probably the best and easiest though).

The left one can be substituted with a green highlighter dissolved in water, but it doesn't produce that nice line when you shine the laser through. Fluorescein is a pretty common fluorescence standard, so it's quite possible that your lab would have some. If not, you can actually just buy it on Amazon. It dissolves in mildly basic aqueous conditions (~0.1 M NaOH is what I use)

We use a UV laser diode for the light source, something like this.

Hope that helps!

Regarding the laser...

1. Use something like this plug-in laser
   
   
2. Use this sensor
   
   That sensor comes with editable programming code that allows you to control whether it should power on/off an object (eg. an alarm) for your choice of duration, based on a trigger of being hit by a laser, or held focus by a laser, or losing focus of a laser. For your use case you'd program this sensor to get triggered when the laser stops hitting it, at which time it will supply power to an alarm for a duration of say 1 hour, regardless of the laser starts hitting it again.
   
   EDIT: That sensor can have a switch between it and its own power source, so that players can throw the switch to turn off the sensor and the alarm.

>(I may get some basic online courses on electrical engineering or optical science if thats a good idea)

Electro-optics is literally my major so ask away


But 10W is insanely too much power for any application other than engraving or bring reckless.

For a first build i would recommend not going above 10-20mW because of how dangerous it gets. But you can buy lasers built into housings like this and use a lighter driver

Used these mounts.

Three-axis Adjustable Holder Diameter 19.5mm Heatsink for 18mm Laser Diode Module https://www.amazon.com/dp/B07C4Q5HLC/ref=cm_sw_r_cp_api_b566Bb45NRTVB

https://www.amazon.com/Lights88-532nm-Green-Module-moduler/dp/B076HMNN4K/ref=pd_sbs_328_1/138-2880455-8222035?_encoding=UTF8&pd_rd_i=B076HMNN4K&pd_rd_r=a09c1d4c-783b-11e9-a004-a1acb67dd0d5&pd_rd_w=MOnWu&pd_rd_wg=GZhd0&pf_rd_p=588939de-d3f8-42f1-a3d8-d556eae5797d&pf_rd_r=1ZNCRF9GESE4D0MWY5CC&psc=1&refRID=1ZNCRF9GESE4D0MWY5CC

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Title|Recreating the 40-Yard Dash Speed Test with a Raspberry Pi and Phototransistors
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Description|In this video, we show how we created the NFL's 40-yard dash speed test that is used by scouts to evaluate the speed of potential American football prospects. To recreate the test, we used a Raspberry Pi, phototransistors, laser diodes, resistors, a analog-to-digital converter, and a simple Python stopwatch program. Using these materials, we created two laser tripwires separated by 40 yards. One tripwire starts the stopwatch, and the other stops the stopwatch. ⤶⤶For more information on the code and our wiring setup, visit our github repository: https://github.com/chris-gong/forty-yard-dash-rpi⤶⤶Thanks again to our friends for helping us out: Alex, Taylor, Ethan, Zach, and Grant⤶⤶Join our discord: https://discord.gg/2xbR5qT⤶Support us on patreon: https://www.patreon.com/flopperam⤶⤶Social media links:⤶Twitter: https://twitter.com/Flopperam⤶Instagram: https://www.instagram.com/flopperam/⤶Facebook: https://www.facebook.com/flopperam⤶Alex's Twitter: https://twitter.com/uhFakie⤶⤶Materials Used:⤶Raspberry Pi: https://www.amazon.com/ELEMENT-Element14-Raspberry-Pi-Motherboard/dp/B07BDR5PDW/ref=sr_1_4?keywords=raspberry+pi&qid=1565404835&s=gateway&sr=8-4⤶Phototransistors: https://www.amazon.com/HiLetgo-Phototransistor-Photosensitive-Sensitive-Sensors/dp/B00M1PMHO4/ref=sr_1_2?keywords=phototransistor&qid=1565404855&s=gateway&sr=8-2⤶Laser diodes: https://www.amazon.com/HiLetgo-10pcs-650nm-Diode-Laser/dp/B071FT9HSV/ref=sr_1_3?keywords=laser+diode&qid=1565404876&s=gateway&sr=8-3⤶Breadboards: https://www.amazon.com/Breadboards-Solderless-Breadboard-Distribution-Connecting/dp/B07DL13RZH/ref=sr_1_3?keywords=breadboard&qid=1565404905&s=gateway&sr=8-3⤶Battery holders: https://www.amazon.com/LAMPVPATH-Battery-Holder-Bundle-Single/dp/B07BNMKNQX/ref=sr_1_5?keywords=battery+holder&qid=1565405063&s=gateway&sr=8-5⤶Analog-to-Digital converter: https://www.amazon.com/HiLetgo-Converter-Programmable-Amplifier-Development/dp/B01DLHKMO2/ref=sr_1_3?keywords=raspberry+pi+adc&qid=1565405226&s=gateway&sr=8-3⤶Breadboard wires: https://www.amazon.com/EDGELEC-Breadboard-Optional-Assorted-Multicolored/dp/B07GD2BWPY/ref=sr_1_3?keywords=breadboard+wires&qid=1565404930&s=gateway&sr=8-3⤶10k ohm resistors: https://www.amazon.com/Projects-100EP51210K0-10k-Resistors-Pack/dp/B0185FIOTA/ref=sr_1_3?keywords=10k+ohm+resistors&qid=1565404944&s=gateway&sr=8-3⤶⤶Music Creds⤶Song: Royalty Free Music | Victory - Hip Hop Beat | No Copyright Instrumental⤶Video Link: https://www.youtube.com/watch?v=4D-LoMTbvx4⤶Music & Arrangement: Marjan Gjorgjievski⤶Mix & Mastering: Marjan Gjorgjievski⤶⤶Song: Lakey Inspired - Blossom⤶Video Link: https://www.youtube.com/watch?v=B7ArnZl_zBU⤶Follow the artist, Lakey Inspired:⤶https://www.facebook.com/LAKEYINSPIRED⤶https://soundcloud.com/lakeyinspired⤶http://instagram.com/lakeyinspired⤶⤶#nfl #40yarddash #raspberrypi

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Wattage depends on what you’re trying to do, but you won’t find a unit small enough for that job above 1 or 2 Watts. That should be enough to engrave woods and acrylic, and probably cut almost nothing.

This could work.
https://www.amazon.com/Focusable-Cutting-Burning-Matches-Adapter/dp/B06WVHS3K5/ref=mp_s_a_1_3?ie=UTF8&qid=1537218156&sr=8-3&pi=AC_SX236_SY340_QL65&keywords=laser+2watt&dpPl=1&dpID=51m7Akat%2BbL&ref=plSrch

The issues with a project like that are:

1. Unenclosed, so you’ll need proper safety glasses for another $50-$100 as well as fume extraction unless you run it outside.
   
   
2. The print bed will be wrong, and depending on the wavelength of the laser, could reflect it with unfortunate results. You’ll need to rebuild the lower area to capture and diffuse the laser without damaging anything.
   
   I tried to do exactly the same thing last year and eventually realized that buying a small Chinese laser cutter would be easier, safer, more powerful, and generally far more useful, not to mention I wouldn’t lose my 3D printer to the cause. It can be done though, if that’s what you really want.
   
   

With an LED holder and a little bit of work you can add something like this to it.

At 5v the dot is pretty visible.

The original LAM comes with a low power flashlight and a red LED mocking a laser. I installed my own laser by removing some material on the inside, disconnecting the original wires, and connecting the lasers. I'm still figuring out someway to set windage and elevation but for now I'm just shimming it with electrical tape.

I bought a laser crosshair that runs off of a 5V wall-wart. It's mounted on the garage ceiling and lined up to a point on my dashboard. I combined that with a simple magnetic switch wired from the garage door so it only comes on when the door is open.

The laser lines are long enough so I can use it to guide me in.

This has allowed me to place my car within 1/4" of where I need it to be so I can open the doors and trunk without banging into something (There is literally 1/2" clearance for a couple of the doors).

Hope this helps.

Well, I got the ones off Amazon instead, since I'm with a research organization and admin frowns on the use of eBay unless necessary. I got these: http://www.amazon.com/gp/product/B00HHHOU1Y/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1

They have the x-drive board built in.

Amazon has a couple of sellers with modules cheaper than pointers....

http://www.amazon.com/dp/B00HFHPPQ0/ref=pe_385040_127541860_TE_3p_dp_1

first google result You'll also have to find a constant current laser diode driver, a module to mount the diode in which has a lens, and a heat sink to put the module on or in.

You can also get ready made modules like this But you would need to get a big heatsink for it. That tiny driver board might overheat as well so this probably isn't the ideal module for engraving. You'll want to end up with something like this. IF you want to make it yourself and need it to run constantly, I'd suggest drilling a hole in a computer CPU heartsink for the module.

You can find a lot more information about how to mount, drive, and assemble these things at LaserPointerForums and PhotonLexicon DIY sections. There is also /r/lasers Some of the message board members run web stores and sell all sorts of useful parts for this sort of thing, often made at home. The guy I used to buy from is closed now though. PhotonLexicon is mostly focused on laser shows, and LPF is more about laser pointers, but between the two you should be able to figure out what you need.

I believe the most common donor projector is a Casio m140, but it's been a long time since I've been messing with lasers and there may be better sources now.

https://www.amazon.com/445nm-Diode-Copper-Module-Element/dp/B00HFHJBDI/ref=sr_1_1?ie=UTF8&qid=1482526661&sr=8-1&keywords=2+watt+laser
This is the driver: http://www.ebay.com/itm/5A-analog-linear-PWM-laser-diode-driver-with-thermal-protection-/162291013120?hash=item25c94c5600:g:w7oAAOSwiYFXHE-T
I have a feeling that maybe the driver isn't allowing the full current through to the laser.... I'm considering running without the driver and seeing how that goes.

Off the cuff suggestion:

Can it be red? You can pick up some cheap red laser lines intended to be used on circular saws. Retro fit the battery to a controllable power supply. You can get them at Harbor Freight or pricy ones via Amazon

Found one for 25$

https://www.amazon.com/532nm-Generator-Module-Alignment-DC3-5V/dp/B00UBQXJFQ/ref=sr_1_9?ie=UTF8&qid=1541054043&sr=8-9&keywords=laser+line+diode