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First laser(s) build ever!

thefiredlaser

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Jan 14, 2019
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Hey,

Just found the forum a couple of days ago and it has helped me quite a lot. I must admit that this is my first build ever. I´d like to build an laser with multiple laser diodes where you can control the power output to be able to decide temperature on the decided object to be burned/heated and burn/heat things evenly and produce vapor.

I´ve put together a list of things that I need to purchase to be able to build it, but I would really appreciate some input and thoughts on the parts list. Am I missing something, maybe overthinking the whole thing, too little parts for multiple diodes?

1- PCB Board
1- Solder
1- Soldering Iron
1-Adjustable Voltage Regulator LM317T
1- 100 ohm Potentiometer
1- 47uf 35v Capacitor
1- Power Switch
1- 12x30mm Aixiz laser housing
2- 10 ohm Resistors
1- 1N4001 Rectifier Diode
2- Wire Red and Black
6 volt Power source

---

Then I´m thinking of buying a couple of these lasers, but wich model to buy that can burn the best and at the most cost effective price?

Nichia NDU7216, NDU7375, NDV7116, NDV7375, NDB7K75, NDA7175, NDS7175E, NDG7K75T

---

Am I missing anything else? Like lenses to be able to focus the laser beam or will the Aixix housing solve that issue? Haven't been able to figure this one out.

Any help will be greatly appreciated! Love from the cold Nordics.
 



Immo1282

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Hi! You've got off to a good start - but one thing you really need to know when you start working with lasers is how damn sensitive most Laser Diodes are. ESD (electrostatic discharge), Overheating, spikes of voltage and current and anything other than very careful physical handling of laser diodes can be enough to kill them outright, or catastrophically damage them so they no longer lase, but just emit a disappointing glow.

To mitigate these, you'd do well to set up a workspace with a soldering iron which has it's tip grounded, an anti-static wrist strap also grounded and to buy your diodes for your first project pre-pressed into modules. I have lost ~£50 of diodes because I was being too naive about keeping the diodes safe from these dangers.

Not added to your list is any consideration for heat-sinking - Yes the Aixiz style modules come with the 9x0.5mm thread used by most inexpensive lenses sold for DIY Laser builds, but if you want to use any diodes that burn or heat up whatever surface they're hitting, you will need to either run them for only a very few seconds at a time and leave them to cool for a long time in-between uses, use modules with larger thermal mass, or fabricate a larger heatsink for your diodes.

One other thing to note - Lasers that can burn materials can also burn your eyes in a fraction of a second. It's all well and good to say "It won't be me, I'll be careful" - but accidents happen and the best we can do here is to protect what we have - so factor in a decent set of laser-safety goggles that are suited for the wavelength of laser light you'll be dealing with.

Don't hesitate to ask around - there are some really experienced people here who've built all sorts of stuff that will most likely be happy to help out :)

Edit: I would also post in the Welcome section of the forum with a brief introduction - If we know a bit about you then usually more people will weigh in and help out!
 

diachi

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Feb 22, 2008
Messages
9,688
Points
113
Hey,

Just found the forum a couple of days ago and it has helped me quite a lot. I must admit that this is my first build ever. I´d like to build an laser with multiple laser diodes where you can control the power output to be able to decide temperature on the decided object to be burned/heated and burn/heat things evenly and produce vapor.

I´ve put together a list of things that I need to purchase to be able to build it, but I would really appreciate some input and thoughts on the parts list. Am I missing something, maybe overthinking the whole thing, too little parts for multiple diodes?

1- PCB Board
1- Solder
1- Soldering Iron
1-Adjustable Voltage Regulator LM317T
1- 100 ohm Potentiometer
1- 47uf 35v Capacitor
1- Power Switch
1- 12x30mm Aixiz laser housing
2- 10 ohm Resistors
1- 1N4001 Rectifier Diode
2- Wire Red and Black
6 volt Power source

---

Then I´m thinking of buying a couple of these lasers, but wich model to buy that can burn the best and at the most cost effective price?

Nichia NDU7216, NDU7375, NDV7116, NDV7375, NDB7K75, NDA7175, NDS7175E, NDG7K75T

---

Am I missing anything else? Like lenses to be able to focus the laser beam or will the Aixix housing solve that issue? Haven't been able to figure this one out.

Any help will be greatly appreciated! Love from the cold Nordics.

You'll have a hard time running at least some of the diodes (if not all, I never checked) that you listed with a 6V power supply and an LM317. In constant current mode the input to the LM317 must be 2.5V higher than the output voltage. 1.25V for the minimum dropout + 1.25V across the current sense resistor.

With 6V in and a 2.5V drop your maximum output voltage is 3.5V, which is below threshold for many, if not all of those diodes.

Some of those diodes are also rated for higher currents than can be supplied by an LM317 (1.5A max, best to run it <1A with a heatsink).

Did you check the power ratings on your resistors and potentiometer? They need to be suitably rated to handle the current you're running.

Edit: What circuit are you planning to use?

You should get more rectifier diodes to build a test load so that you can properly set the current from the driver.

A heatsink for your Aixiz module might be wise.

Safety glasses? Have you got any experience with high power lasers? Solder? Electronics design?
 

thefiredlaser

New member
Joined
Jan 14, 2019
Messages
9
Points
3
Hi! You've got off to a good start - but one thing you really need to know when you start working with lasers is how damn sensitive most Laser Diodes are. ESD (electrostatic discharge), Overheating, spikes of voltage and current and anything other than very careful physical handling of laser diodes can be enough to kill them outright, or catastrophically damage them so they no longer lase, but just emit a disappointing glow.

To mitigate these, you'd do well to set up a workspace with a soldering iron which has it's tip grounded, an anti-static wrist strap also grounded and to buy your diodes for your first project pre-pressed into modules. I have lost ~£50 of diodes because I was being too naive about keeping the diodes safe from these dangers.

Not added to your list is any consideration for heat-sinking - Yes the Aixiz style modules come with the 9x0.5mm thread used by most inexpensive lenses sold for DIY Laser builds, but if you want to use any diodes that burn or heat up whatever surface they're hitting, you will need to either run them for only a very few seconds at a time and leave them to cool for a long time in-between uses, use modules with larger thermal mass, or fabricate a larger heatsink for your diodes.

One other thing to note - Lasers that can burn materials can also burn your eyes in a fraction of a second. It's all well and good to say "It won't be me, I'll be careful" - but accidents happen and the best we can do here is to protect what we have - so factor in a decent set of laser-safety goggles that are suited for the wavelength of laser light you'll be dealing with.

Don't hesitate to ask around - there are some really experienced people here who've built all sorts of stuff that will most likely be happy to help out :)

Edit: I would also post in the Welcome section of the forum with a brief introduction - If we know a bit about you then usually more people will weigh in and help out!
--------
Thanks for the input and advice Immo! Really appreciate it.

Heatsink will be thought of and will probably have one made for the project since i dont think there are any out there that will fit the use.. :(

What are you using your lasers for? :)
 

Immo1282

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Messages
563
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Take a look at some of the handheld projects for heatsinks - the lab-style "XYZ" mounts that DTR shows on his page for 20mm modules might be useful for you to look at - they'll take a 20mm copper module and provide you a chunky block of aluminum that you can bolt down.

What are you using your lasers for? :)
Mostly fun at this stage - Haven't got tired of how pretty beams look in the dark, and living near fairly quiet bits of the Somerset countryside in the UK lets me play a bit outside too... Take a look at some of the pictures in the Media Section - there are some members who've produced some really cool art with their lasers! Got fairly tired of burning things quite quickly (as did my landlord after I'd set off the fire alarm with them...) and have been interested in the science as well as the Electronics side. Once I've finished off some of the builds that are currently crossed out in my signature, I'm going to resume work on designing a smart driver PCB, current adjustable digitally instead of the typical potentiometer or TTL signals.
 

thefiredlaser

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Messages
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Points
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You'll have a hard time running at least some of the diodes (if not all, I never checked) that you listed with a 6V power supply and an LM317. In constant current mode the input to the LM317 must be 2.5V higher than the output voltage. 1.25V for the minimum dropout + 1.25V across the current sense resistor.

With 6V in and a 2.5V drop your maximum output voltage is 3.5V, which is below threshold for many, if not all of those diodes.

Some of those diodes are also rated for higher currents than can be supplied by an LM317 (1.5A max, best to run it <1A with a heatsink).

Did you check the power ratings on your resistors and potentiometer? They need to be suitably rated to handle the current you're running.

Edit: What circuit are you planning to use?

You should get more rectifier diodes to build a test load so that you can properly set the current from the driver.

A heatsink for your Aixiz module might be wise.

Safety glasses? Have you got any experience with high power lasers? Solder? Electronics design?
-----

I was suspecting that, I´ll probably have to bump up everything in the list I set up to support more power. I made the list for a single laser diode but after realizing that one laser wouldn't be enough to burn and produce enough smoke I decided to add more lasers. Will have to bump up backend specs to support the added lasers. What would you use to support 4-5 lasers?

I haven't ordered anything yet tbh, wanted to check in here first and get your opinion. Good that I did since I was underestimating things.

By circuit do you mean what board? Was thinking of using pcb boards to build it.

Will get safety glasses for both me and the doggo. Just in case.

No experience with lasers except for playing with lasers as a kid and knowing that dvd players have them.. :unsure:

I do have experience with soldering from modifying electronics.

No experience in Electronics design. Do you know any good books/pages that I can read to learn more?
 

Immo1282

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Why do you believe 1 laser not to be able to burn and produce smoke? My handheld 1W blue (445nm) can produce smoke in 4-5s unfocused and instantly when it's focused to a narrow spot. More to the point - there are far better/easier ways to produce smoke if that's what you're after :)

If there's really going to be a lot of smoke you may also need to consider what happens when particles of smoke land on the lens of a laser pumping out many watts of light - they could burn onto the lens and cause damage to it or the diode.
 

thefiredlaser

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Why do you believe 1 laser not to be able to burn and produce smoke? My handheld 1W blue (445nm) can produce smoke in 4-5s unfocused and instantly when it's focused to a narrow spot. More to the point - there are far better/easier ways to produce smoke if that's what you're after :)

If there's really going to be a lot of smoke you may also need to consider what happens when particles of smoke land on the lens of a laser pumping out many watts of light - they could burn onto the lens and cause damage to it or the diode.
-----

I do belive that a single laser will be able to burn, but it will only burn a single point and will always burn on the same location of the thing you´d like to burn. My thought process was that with more laser you´ll be able to burn a bigger area. Maybe this is inecessary?

My thought with this is to encapsulate everything that is going to be burned in a hardened glass chamber and then burn trough the glass. This should work with hardened glass right? :)
 

Immo1282

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Powerful laser diodes are Multimode diodes - i.e. they have multiple emitters and will produce a bar or rectangle instead of a small dot - so it's possible that you wouldn't need multiple. Be careful pointing lasers through glass - as you'll get a surface reflection from both inside and outside of the glass you use which may be dangerous for your eyes...
 

thefiredlaser

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Messages
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Powerful laser diodes are Multimode diodes - i.e. they have multiple emitters and will produce a bar or rectangle instead of a small dot - so it's possible that you wouldn't need multiple. Be careful pointing lasers through glass - as you'll get a surface reflection from both inside and outside of the glass you use which may be dangerous for your eyes...
Thanks Immo! Will have a look at Multimode Diodes. Any brand or manufacturer you'd recommend?
 

Immo1282

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Thanks Immo! Will have a look at Multimode Diodes. Any brand or manufacturer you'd recommend?
You've already looked at some - Most laser diodes which are more than a few hundred milliwatts of power output are multi-mode. Take a look on the Diode listings on DTRs site. Other manufacturers aside from Nichia make them too :)
 

diachi

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Powerful laser diodes are Multimode diodes - i.e. they have multiple emitters and will produce a bar or rectangle instead of a small dot - so it's possible that you wouldn't need multiple.
Multimode diodes are single emitter, being multimode has nothing to do with the number of emitters. It refers to the mode structure of the laser. Multiple emitter diodes do exist, but they come in the form of a bar with discrete emitting areas.

https://www.rp-photonics.com/resonator_modes.html

-----

I was suspecting that, I´ll probably have to bump up everything in the list I set up to support more power. I made the list for a single laser

By circuit do you mean what board? Was thinking of using pcb boards to build it.

Will get safety glasses for both me and the doggo. Just in case.

No experience with lasers except for playing with lasers as a kid and knowing that dvd players have them.. :unsure:

I do have experience with soldering from modifying electronics.

No experience in Electronics design. Do you know any good books/pages that I can read to learn more?
Could just get a single laser that's powerful enough to do what you want. Plenty of options out there.

I mean the schematic for the circuit.

If you have no experience with lasers then I suggest you avoid starting out with something high power. Jumping straight to a high power laser is generally a bad idea.

What is it you're trying to achieve?
 

Immo1282

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Multimode diodes are single emitter, being multimode has nothing to do with the number of emitters. Multiple emitter diodes do exist, but they come in the form of a bar with discrete emitting areas.
Sorry for the misinformation! Seems I need to go back to the books :) Thanks Diachi

If you have no experience with lasers then I suggest you avoid starting out with something high power. Jumping straight to a high power laser is generally a bad idea.
OP, I +1 this suggestion. Build something that uses a cheap diode first so you can get a feel for how stuff works first.
 

smallfreak

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I´d like to build an laser with multiple laser diodes where you can control the power output to be able to decide temperature on the decided object to be burned/heated and burn/heat things evenly and produce vapor.
Lasers are a good choice if you want to apply high energy density on a small spot. Heating things „evenly“ is usually just the oposite of that.

What kind of „things“ do you want to heat and produce vapor of it? This might well influence the overall concept, as it is not enough to throw a Laser beam on „something“ and all is fine. The target must absorb the energy in a way you get the desired result. For instance it‘s not so easy to produce water vapor with a blue Laser shining into clear water, as clear water does not absorbe much of the light energy. And if the beam is strong enough with a good focus, you just get a tiny boiling point and no chance to heat it evenly.

Would you mind to elaborate the project more broadly? Maybe Lasers are not the best option to start with, even if they are cool.

Btw. A circuit with an LM317 is good for a first study lab project, but not very efficient when you want to do some serious Laser work, let alone with multiple diodes. Depending on your application you might be much better off with ready made lab modules with analog or digital regulation interfaces.
 




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