445nm >FIRST BUILD<

[thebushwookie]

Mega-noob to lasers, but im eager to learn

My plan is to build a portable multi-laser.... thing.

It will utilise 3 - 12 diodes and a moving parabolic mirror to change the focus. Much like a reflective telescope, but, well, backwards.

I have been advised against the cheap 808nm 300mW diodes on ebay due to the fact they are not visible and too powerful for a first build.

Instead, i am looking towards 445nm diodes for a build with possibly a car battery for power?

I am new to this, and YES i have read countless FAQ's and tutorials. The main issue i have i would think is just parts.

Where can i get cheap 445nm's and drivers? How many drivers do i need? Can one driver power multiple diodes? How can i calculate the power of my laser and the power it needs?

Thanks in advance

tbw

 

[choi]

Wow. Let me be the first to welcome you to the forum!!
I'm new too, never build a laser but probably read a lot more than you.
Planning on building a white laser but need more time and money for now.
I don't know what you mean about the telescope thingy.
You need laser goggles before you even power up your laser diode!
You don't need a car battery for power that's just ridiculous.
You need a different driver for every laser.
I don't think you'll be able to calculate the power of your diode, you need specialized things for that. The power it needs that's easy just do more reading.
I suggest you do something more simple and don't forget the laser glasses that's important.

 

[weeba2kv]

car battery portable laser...

12 diodes ?

are you going to make a laser pointer the size of a big telescope ?

sorry but i can't give a normal answer to this

 

[Lotus_Darkrose]

I couldn't think of a way to respond either. He did say he read "countless facts and tutorials" before he thought of this...lol

You know how we all love to power lasers with car batteries here on the forums...

 

[LtKernelPanic]

Welcome to LPF!

To answer your questions:

1. There is no such thing as cheap 445 diodes. Buying in lots of 3+ can get them down to about $40 EACH.

2. There is no easy way to drive that many diodes. (there are ways if you're building a projector)

3. You can't easily power more than one diode per driver unless you're building a projector and use a specialized driver setup.

4. Excluding some linear drivers a 12v car battery will blowup most drivers.


That now said let me offer some advise I gave in another thread.


Here's a couple suggestions for doing your first 445nm build:

Host:

I'd stick with a host kit that has the host and matching heatsink. You can get nice kits for $30-40 in the BST or LPS forums here. Several members here also make custom hosts upon request which will obviously cost more.


Driver:

The flexdrive is the king of drivers. A quality single 18650 should give you a decent amount of runtime. For 445 you can also use a microboost too. Just pay attention to their slightly different wiring requirements.

If you can build a simple circuit you can build a LM317 or LM1117 based linear driver. You can see examples of them in my 405nm hotlights build and my 635nm pen build. They're basically the same driver seen here.

Laser driver - It can be done

I decided not to use any filter caps or diodes to save room in my hosts but note while that the drivers I built work fine they will not protect the laser diode against any voltage spikes or if you put the battery in backward like the full driver he shows on that page. Also make sure your resistor(s) is rated for the correct wattage. You the calculator here to find out the values needed for a given mA output.

LM317 Current Calculator - Electric Circuit

If you want a great basic preset linear driver checkout Jib's driver over in the BST forum.

http://laserpointerforums.com/f39/fs-jibs-linear-drivers-500ma-1-3-1-6a-1-8a-60213.html

Two things with linear drivers:

1. You have to use two 3.7v batteries with them vs. only 1 with a flexdrive or microboost.

2. if you build one for use in a high powered laser you'll need to heatsink the regulator. Even though jib's don't necessarily require one I personally would to guarantee stable output.

Whatever driver you use you'll also need to build a test load to use while setting your driver. For higher powered 445 builds like this one six 1N5404 in series with a 5-10w 1 ohm resistor will be fine. There's a basic one on rog8811's site with instructions for use. Note that one uses 1N4001 diodes which are only rated for up to 1 amp. 1N5404s are rated for 3A. Also if you use a flex drive the chip's designer (drlava here on lpf) recommends not using a wire wound resistor as it can damage the driver.


I would also go through this forum and the reviews forum and look at the build people have done as there's a ton of info here.

Good luck!

 

[Lotus_Darkrose]

+1 LtKernelPanic. Some great advice

 

[chefla]

Don't forget that the LM1117 is restricted to 800mA of current. If you want to go beyond that and use linear drivers then I would recommend the 1085 which is rated for up to 3 Amps ( but don't attempt to run your 445 diodes at 3 Amps!!).
You could run your drivers with an 12 V battery. But when using linear drivers all the excess power will be turned into heat. So you better have some decent heatsinks to avoid overheating your drivers.

 

[chefla]

I like the idea with the 12V battery. But I would use a AGM or gel cell type. They are more expensive but safer to handle (no acid to spill!).

3. You can't easily power more than one diode per driver unless you're building a projector and use a specialized driver setup.

I tend to disagree on that point. You could simply use one 1085 to drive two 445 diodes in series. That way you don't dissipate as much heat as with only one diode hooked up to it. I think that is a fairly easy and safe setup, even for beginners.

If you have enough room for a car battery, it should be easy to put a few 1085s and heatsinks in your build.

 

[Asherz]

http://laserpointerforums.com/f65/8-diode-445-build-64296.html

I believe that is essentially what you are trying to achieve, but that would be the "correct" way of going about it, instead of a car battery and a telescope.

I'm sure most people (atleast me anyways) when they joined the hobby thought of the "buy loads of diodes, make massive laser" idea, unfortunately it's never as easy as it seems, or as cheap for that matter to get a result that is actually anything like you intended.

I suggest if you do want to get into the DIY side of lasers, build your self a converted flashlight laser either utilising one of Jayrobs kits, or a custom host possibly machined by some of our forum machinists

then work your way up to possible a large duty cycle lab style laser (or could do this one first) and once you have the basics of how to wire up the drivers, connect the diodes prepare the diodes etc, you'll then have the basic tools and knowledge to start experimenting with ideas, and knowing how to make things more feasible.

If you jump straight into a big project, a lot of money will be wasted and forum members will get frustrated constantly answering basic questions when starting of with some basic builds would have answered most of them already.

Goodluck

 

[chipdouglas]

for driving multiple diodes i would suggest the flexmod p3 you can run 4 diodes off of it and get clost to 1watt out of each

 

[thebushwookie]

Thanks for all the help guys, really appreciate it

Yeah, it seems my idea of lasers is much more simplfied than it is in real life. Multiple lasers will be somewhat more complex to work with, so maybe, i should put that idea to the side.

Still, a single 445 would make a nice first start i think. I'll look into kits.

Thanks again guys

Excuse my primitive GCSE understanding of electronics, im only 16

 

[LtKernelPanic]

+1 LtKernelPanic. Some great advice

:thanks:

I finally decided to start using Text Expander so I can write up a couple detailed replies to common questions so then with a couple keystrokes I can post it without retyping all of it.

Don't forget that the LM1117 is restricted to 800mA of current. If you want to go beyond that and use linear drivers then I would recommend the 1085 which is rated for up to 3 Amps ( but don't attempt to run your 445 diodes at 3 Amps!!).
You could run your drivers with an 12 V battery. But when using linear drivers all the excess power will be turned into heat. So you better have some decent heatsinks to avoid overheating your drivers.

I didn't know that LM1117s are limited to 800ma. I was thinking they were good up to 3A like the trusty LM317. I guess that's s tradeoff for the low dropout? I'll update my snippit.

I do have one question about the LM1805. I see on digikey that there are ones with fixed voltage outputs like 3.3v, 5v, 12v, etc. I assume you need to get one that can output at least the number of volts you need then wire it up like the LM317? I looked at the datasheet but am still a bit confused. I'd like to know a bit more about them before I start suggesting them so I don't give bad info like with the Lm1117.

edit: heh nice timing for my 445 post.

 

[chefla]

I do have one question about the LM1805. I see on digikey that there are ones with fixed voltage outputs like 3.3v, 5v, 12v, etc. I assume you need to get one that can output at least the number of volts you need then wire it up like the LM317? I looked at the datasheet but am still a bit confused. I'd like to know a bit more about them before I start suggesting them so I don't give bad info like with the Lm1117.

You need the 1085-ADJ. The other types are fixed voltage versions. They will not work as current sources. But maybe you wanted to run a 445 diode at 5.0Volt? Nah, bad idea!!! :eg:
And, the wiring on the 1085-ADJ is the same as for the LM317 driver.

 

[Kevlar]

I didn't know that LM1117s are limited to 800ma. I was thinking they were good up to 3A like the trusty LM317.

Actually the LM317 can handle up to 1.5A but that's the max and would have to heatsinked. There are other LM series ICs that go to 3A and 5A (LM338 and LM350)

 

[thebushwookie]

If i were to buy this diode: eBay Link

Which would be the best driver to buy and how would i power it?

 

[chipdouglas]

it depends on the host you want to use. you need to calculate what battery combination your host can take.

if it can only take 2 aa's you will want a boost driver. if it takes a lot of volts you will want a jib driver.

michael.