1st Build; a bit of help please?

[Muttyfutty]

Hi,
I was browsing through the interwebs and I got sucked in to the whole "shiny lasers" thing.
I scoured this forum, a fantastic knowledge base btw, looking up tutorials/hints and tricks etc etc.

I'm looking at building a semi powerful ≈200mW red laser. I have a fair bit of knowledge about lasers and I have been
soldering and making circuits for years. I own a small 5mW green laser and I'm *ahem* Interested in more power.
I have access to a nice (small) lathe and I would love to machine the host/heatsink myself; probably out of aluminum (If I can get it).
Looking through this forum I can tell that safety is Strongly emphasized so I want to assure you that
I'm not some kind of deranged 12 year old boy ; I am definitely getting laser goggles.
Anyways, back on topic. I was just wondering if (any) of these diodes were suitable...
1) Mitsubishi 660nm 200mW
2) 250mW-650nm-Red-laser-diode

I'm planning on using This housing and basically machining my host so that it is an interference fit.
I would probably use a standard lead/acid 12V battery to power the driver/diode at first.
After I make it work, I'll probably invest in some Li-ion batteries or similar. Would a LM317 act as a good driver?
I don't wanna kill my diodes...

To get variable 1.25V - 2.8V.
Any tips, tricks, codes?
:thanks: a bunch.
Regards,
Mike

 

[anselm]

Hello and welcome to the forum!:wave:

Regarding your circuit:
I'm not sure what R2 is doing there, but then again, I don't know very much about circuits.:yabbem:
But you will want to regulate current, not voltage.
The LM317 makes for a very simple and reliable constant current driver, pretty
much perfect for a DIY driver.
Anyways, look here:
Laser driver - It can be done

About the diodes:
yes they seem suitable, but you can get them (much) cheaper, I'd suggest you
talk to member 'scopeguy20', I just received some optical sleds from him today.

 

[Coherent Light]

Welcome to LPF! As anselm said check with scopeguy, and if He's out quite a few members here sell the LPC-815 sled on their retail sites.

 

[Muttyfutty]

Thanks guys!
I'll probably stuck to the driver in your link, as I would hate to get it wrong and stuff my diode...
Sorry for the noobish questions but is there an issue with such a new member like myself buying after 2 posts?
or should I hang around for a bit longer?
Anyways... Since the LPC815/LPC-826 are open can, is there problems regarding extracting them from their sleds?
If a bit of wire/heatsink/swarf found its way onto the unprotected diode will it kill it?
Lucky I live in Malaysia; static is virtually non-existent. we got marble floors here and humidity
is over 70%. That's great for static but will the relatively high humidity kill my exposed diodes?
Cheers,
Mike

 

[Kansas Outcast]

It may be cheaper to get your host off ebay or a seller here and then machine your own heatsink, but then again I don't know aluminum(sp) prices lol, its a shame copper is expensive and looses its shine after a while. I don't see why anyone won't sell to you atleast you aren't like some of the new people that have 2 posts, know nothing about lasers, and want a 1W 445nm beast as their first lol people here will sell if you just tell them a little bit about what all you know and your intentions =) WELCOME

 

[Kevlar]

Thanks guys!
I'll probably stuck to the driver in your link, as I would hate to get it wrong and stuff my diode...
Sorry for the noobish questions but is there an issue with such a new member like myself buying after 2 posts?
or should I hang around for a bit longer?
Anyways... Since the LPC815/LPC-826 are open can, is there problems regarding extracting them from their sleds?
If a bit of wire/heatsink/swarf found its way onto the unprotected diode will it kill it?
Lucky I live in Malaysia; static is virtually non-existent. we got marble floors here and humidity
is over 70%. That's great for static but will the relatively high humidity kill my exposed diodes?
Cheers,
Mike

As far as how long you've been a member or how many posts you have, it all depends on who you are buying from. Most members will sell to just about anyone.

LPC's are not too difficult to extract from the sled. Getting it out of the heatsink without damaging it is sometimes challenging. It's an long open can diode which means there is noting protecting the tiny die and bond wires so you have to be careful.

You could buy the diode extracted, and pressed into an AixiZ module here: http://hightechdealz.com.

There aren't many hosts that I know of that will hold a DIY LM317 based driver using component parts, you would have to use SMD parts. There is a member who makes those and sells them (http://laserpointerforums.com/f39/fs-lm1117-based-linear-driver-1-3a-fixed-60213.html#post851547). I believe he can make one for you to a pre-set current, just shoot him a PM.

 

[Asherz]

Check out:

hightechdealz.com
modwerx.com
stonetek.org

Maybe a few I've forgotten but all really good stores, and owned by members on the forum.

For the build you'll need a diode and a normal aixiz module which'll include the lens setup you need to get it up and running, if you want look for a specific glass lens that's treated for red lasers, allowing for more power. Both the aixiz module and diode can be purchased from the stores above, they are the standard modules used here on the site, if you want to purchase a slightly more expensive one look into meredith modules.

I find this diagram clearer/easier to follow

Another possibility since you mentioned you have a lathe if your feeling adventurious is isntead of putting the diode/driver in a module then putting that in a machined heatsink, machine a specific holder (5.6mm) to directly press the diode into the heatsink acting as a module with better heatsink properties.

Goodluck on your first build!

 

[Muttyfutty]

Thanks,
I'm debating with myself if I should risk getting the sled for a cheaper price.
I have seen the video on how to extract the diode but the fact that its open 'can' makes me nervous;
I have no experience when it comes to extraction.
I think I will try a regular flashlight host and machine a heat sink. Hopefully those Chinese
flashlights have a standard screw thread...:thinking:
The only major problem I'm facing is the heat sink itself.
I've looked on eBay and found aluminum cylindrical bars but the shipping cost is not viable.
My dad has a rather large collection of pewter bars, could this do? Could I melt it down with
an oxy-acetylene blow torch and form it into a nice cylinder, which I can then machine?
Alternatives? please?
Thanks again,
Mike

 

[Kevlar]

I don't think the Chinese flashlights having standard screw threads is an issue. Normally the heatsink just slides in, not threaded in.

Pewter is mostly tin and a bit lead, neither of which have very good thermal conductivity. Stick with Al.

There are several members here who will make you a heatsink, just give them your measurements (or even better, the host itself). But I don't know if with shipping if that would be cheaper than you getting some Al and doing it yourself. Thats if you have the lathe to do it.

 

[Kansas Outcast]

I actually did my first extraction from an old sled that I found in the basement, it's not too hard just getting that little circuitboard off might be hard for me If you have a good soldering gun and a solder removal tool then you shouldnt have much problems with it =) I've also heard of people using exacto(sp) knives on them for a safer heat free way to extract.

 

[LtKernelPanic]

I've built an LM317 based driver using normal parts in a flashlight style host. (See the PHR build thread in my sig) You can do it with a Guidesman or Hotlgights host with a simple mod of the plastic pill. Just make sure the metal back (or any of th epins for that matter) of the LM317 are touching the metal of the host or any bare wires or you will get a short that will likely fry your diode.

In my build I didn't use a cap since I used the host as the negative line back from the diode. I should have put a 1N5001 diode between the positive contact of the host and Vin on the LM317. Next time I do a build I may open it up and splice one in since I've caught myself putting the battery pack in backwards more than once already. If you want to add a cap I'm honestly not sure how you'd do it in a host where you're not using a circuit board to get the positive and negative contacts from. I'd probably also go with a pre-made host/heatsink combo for your first build. There's nothing wrong with DIY -- in fact I really like seeing DIY hosts, but a pre-made combo would make your first build easier and you can take what you learned from it and put towards your next build Trust me there will be a next and another after that and another after that and ano..... .

 

[Muttyfutty]

Hi, sorry for the late reply...
I have begun the search for aluminum...
My school threw out a nice UPS which has 2 17Ah 12V batteries!:drool:
The circuit board has a nice collection of 1/4" thick heatsinks. I calculated the
density to be ≈ 2.65 g/cm3 which is close enough to be aluminum or an alloy.
I have asked my school canteen for aluminum drinks cans etc. they say I should expect >50 by
the end of the week. I'll melt all of them down and mold them into a nice cylinder...
if it's that easy... *Fingers crossed*
If I can get that amount I'm looking at (each can= 1/2 ounce) Just over 1 1/2 pounds of aluminum.
Probably enough...

Anywwaaaayyyyy....
I had a go at extracting a diode I found in a 8X or 16X DVD writer. I tested the polarity with a fluke and I got a
tiny red glow! The case is negative, so I assume I got myself a red laser diode! Is there any way to determine
what voltage/ampage I should pump into this thing? The diode is unmarked...
I'll post pics soon...
Cheers! :beer:
Mike

 

[Kansas Outcast]

I just was reading through a post and another member just posted the diode voltages ill quote him

""""For Red laser diodes the working voltage is ~ 3 VDC
For 445nm Blue laser diodes the working voltage is ~ 4.5 VDC
For 405nm BluRay laser diodes the working voltage is ~ 5.5 VDC

A #18650 lithium ion battery is 4.2 VDC fully charged.

A Red would need a LM1117 step down regulator to deliver 3 VDC.

LarryDFW """

 

[qumefox]

If you need aluminium, as cheap as it is, it's easier to just buy it.

This place specializes in small quantities. And when 1" 6063 rod stock is like, $3.82/ft to me seems like it's not worth it to deal with melting and casting yourself.

Online Metal Store | Small Quantity Metal Orders | Metal Cutting, Sales & Shipping | Buy Steel, Aluminum, Copper, Brass, Stainless | Metal Product Guides at OnlineMetals.com

 

[Muttyfutty]

This place specializes in small quantities. And when 1" 6063 rod stock is like, $3.82/ft to me seems like it's not worth it to deal with melting and casting yourself.

It is cheap, but I'm not in the US; I live in Malaysia. Shipping for a 1ft 1" piece of material costs $84.92!
every hardware shop I've been to has only thin walled 3/4' diameter pipe...
It looks like I don't have much of a choice....
Thanks anyways, Help is always appreciated!
regards,
Mike

 

[Kevlar]

If you could find any machine shops near you, it would be worth a shot asking them to buy a small peice of Al off of them.