DVD burners that rock for diodes.

[VaThInK]

Gazoo: Thanks for your comment. Don't worry mate, you'll get there one day. I had so much fun building mine and I'm sure you would too . In regards to PBS cube, there's a group buy going on over at photonlexicon forum for good quality PBS cubes centered at 633nm and 473nm for $30 a piece. I'm not sure if they are going to take new order though. Just drop by and ask if you're interested. I hope you are not too late to order some.

IgorT: Very good explanation you got there mate :twothumbs. In regards to TEC, I think you kind of misunderstood on their power requirement. TECs are voltage dependent components. Of course you can limit their current to give you variable cooling/heating power, but they will always consume current roughly around what the data sheet state at their rated voltage no matter how much current you supply to them (I use 30A PSU for mine and they only consume about 16A, which is within spec). Giving higher voltage than the rated input could also damage the TEC elements permanently. Lower voltage than the rated spec will results in the TEC consuming less current, hence voltage dependent. With diodes you can feed them 5V even though they're actually rated at 3V. They will eat 3V in the end, but you have to pay great attention to their current requirement since they're current dependent. TECs are similar to light bulbs whereas diodes are exactly the opposite when it comes to power requirement. I hope you understand what I'm trying to say :naughty:.

PS: I just would like to remind you all that open can diodes from Pioneer 112D and Sony 16x drives are the only diodes that I know capable of withstanding current greater than 300mA when properly heatsinked. All the other diodes that I've tried just died sooner or later at this current and I don't know about the others since I haven't tried them all. Right now I'm just using diodes from Pioneer 112D as they yield spectacular results based on my findings.

Cheers guys.

 

[IgorT]

One little thing IgorT, what do you use as power supply and what do you recommend as the less complicated solution. It would be hazard not to use a resistor, so I am gonna buy one, but I wanna know an opinion of a experienced man like you

Well, i'm not really experienced with lasers.. Yet..

But i work with electronics professionally (R&D), so i have some basic knowledge i can apply here..


My power supply is VERY simple, since i want it to work from 3.6V (single cell LiPo, or three AAA NiMhs)

The LiPo i'm using is from a broken helicopter that i desparately wanted to destroy and (if possible) use it's parts for something else..

The LiPo was two 130mAh FullRiver cells wired in series (7.2V), but i rewired it in parallel, to get 260mAh, while still keeping half of the circuitry, that protects it from undervoltage and overcurrent (and exploding )...

I can send you a schematic for the LD "driver" i'm using.. It's extremely simple, but i had problems squeezing it in the little "Phaser" enclosure, so i made another circuit without a board.. (just the parts soldered together)

I can also post pics of it, once done.

Connecting the LD directly to batteries works for some, but a little current limiting is much safer.. And if it's adjustable it's even better.

From my results, i figured out i need only a 1 Ohm resistor to get to a high enough voltage. A small pot is added in series to this, to adjust for less powerfull LDs. A capacitor is in parralel with the power source, to protect from voltage spikes, and a diode before it, to decrease the voltage from 3.6V to 3V.

Now i can finally put it all in that small enclosure i have (it's made for miniature remote controlls, like a garage door opener for example).

I'm also considering to put a special warning LED with integrated circuitry, that would warn me if the voltage drops too low (in case the LiPo's PCB doesn't work well after rewireing..


Of course, if you don't have enough experience, (or many LDs to kill) you'd be better off using a more "complicated" (safer) driver circuit. Like the one with the LM317. But you'd still need a way of measuring the current, while setting it up.

Then you need a 6V power source and a larger enclosure, to fit all the batteries (5x AAA NiMhs)... A two cell LiPo would also do and be smaller, but more expensive. Especially one with protection circuitry.. They also need special chargers...

If i forgot something, just ask...

 

[IgorT]

IgorT: Very good explanation you got there mate :twothumbs. In regards to TEC, I think you kind of misunderstood on their power requirement. TECs are voltage dependent components. Of course you can limit their current to give you variable cooling/heating power, but they will always consume current roughly around what the data sheet state at their rated voltage no matter how much current you supply to them (I use 30A PSU for mine and they only consume about 16A, which is within spec). Giving higher voltage than the rated input could also damage the TEC elements permanently. Lower voltage than the rated spec will results in the TEC consuming less current, hence voltage dependent. With diodes you can feed them 5V even though they're actually rated at 3V. They will eat 3V in the end, but you have to pay great attention to their current requirement since they're current dependent. TECs are similar to light bulbs whereas diodes are exactly the opposite when it comes to power requirement. I hope you understand what I'm trying to say :naughty:.

I know what you mean, but since my TEC is rated for 1.9V, while my power supply is 3V, i have to either use diodes in series, to lower the voltage acordingly, or use a resistor to limit the current, since at 3V it would consume 50% more power and probably kill itself.. As you said yourself, they are voltage dependant, so i need to take care of that...

I am new to lasers and TECs as well, but i have some experience with electronics, since i have to do it for work (R&D)...


EDIT: So your TEC is rated for 3V? And you use some diodes, to drop the voltage from 5 to approx 3V? That was the info i was looking for..

EDIT EDIT: I just had this funny thought, that if you were to overdrive a TEC it would require cooling, maybe by another TEC..

 

[HRUDKA]

Yep, Im gonna use the way with the LM317, because it is safer, as you say. If I understand I need to get current under 250mA and voltage about 6V? OMG its too much, isnt it? It would be written somewhere on the burner, what voltage does it require?

 

[IgorT]

PS: I just would like to remind you all that open can diodes from Pioneer 112D and Sony 16x drives are the only diodes that I know capable of withstanding current greater than 300mA when properly heatsinked. All the other diodes that I've tried just died sooner or later at this current and I don't know about the others since I haven't tried them all. Right now I'm just using diodes from Pioneer 112D as they yield spectacular results based on my findings.

You just have to make me drool, don't you.. I really need to get that Pioneer drive..

Unfortunatelly my source of free LDs is somewhat limited to Samsung.. I could get lucky one day, but not "Pioneer-112D" lucky...

I'm happy with the TS-H552 ones right now, since the one i'm playing with right now, did 280mA continuous, just by being glued onto a small CPU heatsink.
Now i'm putting it in a small enclosure with a LiPo and a small protection circuit.. Wish me luck with the positioning of the optics.. (i don't have the aixiz modules yet)

BTW: Were those Sony 16x LDs from a group buy not rated for only 80mA continuous? Or was that 80mW continuous? Or are you talking about different ones?

 

[IgorT]

Yep, Im gonna use the way with the LM317, because it is safer, as you say. If I understand I need to get current under 250mA and voltage about 6V? OMG its too much, isnt it? It would be written somewhere on the burner, what voltage does it require?

You misunderstood me.. Voltage INTO the LM317 is 6V. Once it gets to the LD it's only 3V and the current is regulated.

If you use that circuit, you don't have to worry too much.. Just make sure you're grounded whenever handling a LD, and when you build the circuit, start at a smaller current and slowly work up from there..

I'm hoping you do have a multimeter, right?

 

[HRUDKA]

You misunderstood me.. Voltage INTO the LM317 is 6V. Once it gets to the LD it's only 3V and the current is regulated.

If you use that circuit, you don't have to worry too much.. Just make sure you're grounded whenever handling a LD, and when you build the circuit, start at a smaller current and slowly work up from there..

I'm hoping you do have a multimeter, right?

Yes, thats EXACTLY what I thought, I ve just expressed like a newbie Thanks for help, btw how much does LM317 cost in US or whatever youre from? Im from CZ, so its a little bit harder to hunt out these things,..and I worry, that it would be definitely more expensive then in US

Of course I have a multimeter, heh Its a basic tool in the house in these days

OK I ve found it in our CZ eshops, its just a funny prize - only about 0.4 in USD. The shipping will be more expensive then the main product, LMAO

 

[IgorT]

Yes, thats EXACTLY what I thought, I ve just expressed like a newbie Thanks for help, btw how much does LM317 cost in US or whatever youre from? Im from CZ, so its a little bit harder to hunt out these things,..and I worry, that it would be definitely more expensive then in US

You don't have to worry about the cost of a LM317.. It's such a basic component, it should be pennies, no matter where you live.. I'm from Slovenia, BTW, not the states.. So i'm a little closer to you..

Just make sure, you get the big one.. The one with a metal piece on top, with a screw hole.. Those can handle more current, than the small ones and you can mount them on a heat sink if needed..

If you get the small ones, you can solder three in parallel, and they could do 300mA, but that would be close to their limit..


BTW: What will you be using as a power source? Do you have a lab PSU, or is it gonna be batteries?

If you have a nice PSU, you can limit the max. current there, just in case something goes wrong with the circuit.. But that can only happen if you wire it wrong..

On a PSU you can also monitor the current going through the LD, instead of putting the multimeter in series.. That's how i tuned the circuit, before using a battery with it. It's best to leave the diode soldered to the driver constantly, it's harder to kill it that way..


Anyway, good luck!


EDIT: I see you found the price, while i was writing..

 

[HRUDKA]

I had PSU, but its lost somewhere in old stuff, coz I havent used it for a long time. It was an old type of PSU, so I dun think, that the it would be easier to handle then with the batteries, anyway. So I will use the batts.

I found the type with max. 1.5A output, it would be enough.

 

[IgorT]

Ok, here are some pics of my "Phaser"...

The first is a part of a miniature enclosure with a LiPo, a switch and some very simple protection circuitry.. It's not yet wired completely, and it lacks the LiPo protection PCB... The switch is positioned at such a weird angle, cos the enclosure had a button hole there.. It takes a lot of place this way, so i had to solder the components together without a board...

The second is the LD, glued to two IC heatsinks and an adjustable lense holder on top.

It's very hard to position the lense perfectly for max output.. But once i'm done it will all fit into the nice small enclosure and work nicely.. (I hope... )


Wish me luck!


Igor

 

[IgorT]

One question guys.... How many mA does a 16x LD usually require to do some "burning"?

Someone said the Sony 16x LD from a group buy can light a match at only 150mA.. Is this true? What is the output power at that current?



I just finished building my laser and managed to make a nice narrow beam.. The current going through it is set to a little less than 200mA.

Do i have to focus the beam much narrower? What distance should it be focused at to light a match?

It could be i just have bad optics and it'll get better with the AixiZ module..

Anyway, here is the pic of the finished "phaser"... It came out very small, just like i wanted it.. The enclosure is meant for making remotes, like for a garage door opener or something...

Specs:

LD: TS-H552 16x at 200mA
Optics: Scavanged from a cheap laser pointer
Power supply: 260mAh LiPo with protection circuitry.
LD Driver: Simple protection circuitry with current adjustment possibility.
Dimensions: 74x44x18mm
Output power: God only knows... I could compare it to a known power LD tho, using a solar cell..

 

[VaThInK]

My TEC is rated at 15V and I was supplying 12V to it. In your case you could use a series of power diodes to drop the voltage down or better yet use a voltage regulator.

About LM317 or similar voltage regulators, they can work in 2 ways. To regulate voltage or to regulate current. They can't do both at the same time. You will need 2 of them working together to regulate current and voltage. So, if you use them as current regulator, the output voltage would be input voltage minus their voltage drop. Example: 6V - .6V = 5.4V for LDO regulator. 5V is safe though to use with laser diodes. I always power mine with 5V and in fact commercially made ones usually use 5V anyway.

The Sony 16x LD I mentioned is not the ones from GB as they're closed can. I had a Sony 16x drive that uses open can just like with Pioneer 112D. With the GB LDs 150mA ~ 200mA is good.

For burning, adjust the beam diameter as tight as you can. This way will provide more power per area. No point in having 200mW at 10cm diameter. It's just gonna act like a mini flashlight and lose its power density. Ideally, you would want to focus all of the optical power to 1 tiny spot to achieve maximum burning capability. The focus distance would depends on how far away is the object. Green laser doesn't really need to be adjusted though as the beam diameter at the aperture is already very tight (~1mm compared to ~5mm for direct injected red), so you just need to make the beam parallel and maintain it.

PS: Sorry IgorT, when I said diodes in my previous post I was referring to laser diodes instead. Sorry for the confusion .

 

[MatajumotorS]

I did get open can LD from LiteON LH-20A1P it is 20x.
At 200mA it gets little warm after 5min in Axiz module. Had not tested it at higer rates. But it seems to me higer power than my previous LD with closed can from 16x, and it runs Mutch cooler.

Question:
Do someone get some artifacts in LD beam of theese diodes? It is second one that i got. With optics there is some kind of "wings" line like in beam, well seen at 2-10m distance. Without the optic beam patern is not soft oval linear, but there is some kind of lines on sides of oval, causing the "wings". Will post pictures on monday.

Someone seen something like that?

Here are the pictures.
The LD from LiteOn LH-20A1P

http://www.bildez.lv/bildes/matajumotors/laser/orig/1193666321.jpg

Beam with no optic

http://www.bildez.lv/bildes/matajumotors/laser/orig/1193666323.jpg
Do You see the lines? This is white A4 paper under the ruller (ruller used to focus the camera..)

And beam with optics at 5 meter distance

http://www.bildez.lv/bildes/matajumotors/laser/orig/1193666325.jpg

What do you think about that?
IR LD has same "wings" in beam (with other optic)
Optic is not involved, because with other LD's witch has no lines in beam - has no "wings".

 

[IgorT]

My TEC is rated at 15V and I was supplying 12V to it. In your case you could use a series of power diodes to drop the voltage down or better yet use a voltage regulator.

With just 2 diodes in series i'd get just about the right voltage for my TEC, 1.8V... I'd rather have it slightly "underdriven" than "overdriven".. It's very good at cooling as it is.

5V is safe though to use with laser diodes. I always power mine with 5V and in fact commercially made ones usually use 5V anyway.

So when you are talking about how many mA's is going through a LD you mean at 5V?

This, of course is a completely different story.. Since my power supply is 3V i could let more current through without worying about killing it...
I think i'll set mine to 300mA. I already tested it at 280 with no problems..


Otherwise i know how voltage regulators work. I often use them in devices i design for work. I have to develope all kinds of (sometimes) weird devices, so i know my way around electronics.

I just don't know much about lasers yet. The info i need is about LDs..

The Sony 16x LD I mentioned is not the ones from GB as they're closed can. I had a Sony 16x drive that uses open can just like with Pioneer 112D. With the GB LDs 150mA ~ 200mA is good.

Is this 150mA ~ 200mA at 5V? This is what i need to know.

The power going to the LD would then be greater, than at the same current but lower voltage... To get a similiar result i could then raise the current to get approx the same power going into the LD. (or rather a little less for longer life)

Thanks!

Igor

 

[VaThInK]

Is this 150mA ~ 200mA at 5V? This is what i need to know.

The power going to the LD would then be greater, than at the same current but lower voltage... To get a similiar result i could then raise the current to get approx the same power going into the LD. (or rather a little less for longer life)

Thanks!

Igor

Yes it's at 5V. As far as I know LDs will clamp this voltage to whatever they require (3V for instance and not eating the whole 5V). So you are gonna end up with the same wattage just like if you are using 3V power source.

Yeah I figured you would have strong knowledge about voltage regulators. I made that post simply to help clarify your post below.

You misunderstood me.. Voltage INTO the LM317 is 6V. Once it gets to the LD it's only 3V and the current is regulated.

Note: In the second quote you actually said that the LD is only going to consume 3V (output from LM317 isn't going to be 3V, more like a bit <6V), but then in the first quote you said "The power going to the LD would then be greater".

 

[Phenol]

Hello, I am new to this forum, new to harvesting laser LEDs from DVD burners as well.
Recently I got a Lite-on LH-20A1P drive and pulled both leds out. The second thing I felt like I must do was construct a current source based on an op amp and a darlington pnp transistor. Since most such circuits require that the LED's anode be connected to the positive rail thus putting +Ucc to the metal case + heatsink if present, I wanted to redesign it so that the LED is in common cathode configuration and all metal parts be at ground potential. I did manage to come up with a working solution pumping 150mA thru the red LED, the only drawback being that the stability of the current setting is dependent on the stability of the power supply. As such I used a 7805 linear regulator which proved decent in this respect...
The key moment (which killed the infrared led obtained from that same drive) was that a frequency compensation cap on one of the op amp inputs caused a few microsecond-long current overshoot /spike/ during power-up that obviously exceeded the maximum optical power density this LED's facet could handle, thus resulting in what is known as COD /catastrophic optical destruction/. The junction still worked ok, as the forward drop across it remained as it used to be before facet's demise /about 2 volts for the infrared led/. This means that, with fair heat dissipation, the junction may survive applying too much current, but the facet could be damaged in an instant if the 'hyper' power is maintained long enough. If you go through various datasheets of laser leds in this power range, you will notice that the pulse output power is as much as 3 times higher than the specified CW, but for pulse width <30ns and duty cycle <35% . Anything exceeding these values is likely to casue premature facet disruption...
I corrected this annoying issue and, just to further smooth-out eventual transients, i connected a 1uF ceramic cap in parralel with the RED led. The scope verifies that the current ramps up gradually now.
As I have no idea what the specs of my red 'gem' are, I'm reluctant to run it much higher than 150mA. Even at that current, using a lens and a body from a $1 key-chain pointer, it is able to ignite matches in a second and punch a hole through a black floppy disk at a distance of 10 cm in less than a minute with a well focused beam.
A well-desined ARC lens will yield even more power and focusing precision. Some of those chinese cheapos never quite managed to focus in a well-defined spot without many side artefacts... A good source is Roithner, Austria. They ship collimator lenses in any quantity.
Igor, I saw the photo of your 'blaster' and I noticed that the beam aperture is somewhat narrow. I used a similar set-up for my experiments and I discovered that the 'burning efficiency' increased when I increased the diameter of the aperture on the focusing nut. Pehaps a small circular aperture makes the projection more dot-like, as opposed to the 'bar-like' spot produced by most low-power leds...however this may effectively prevent some of the 'burning power' from escaping the aperture.
I will soon be buying a 20x LG drive. Wonder what the LEDs are going to be like. I am beginning to want a closed-can specimen for the sake of reliability. Open-can leds may dissipate heat better, but are susceptible to mechanical damage and environmental contaminants...
My goal now is to find good lenses. I bought all key-chain lasers in my town and only one or two had satisfactory lenses without much scratches and other frightening optical defects......

 

[laserblue]

Where do you get the collimator lens?

 

[Phenol]

http://www.roithner-laser.com

Below is their response. Prices are available on their website.

Thank you for your inquiry.

The GS-7020-2C is in stock and the price is EUR 1,81 / pc.
Shipping and handling: EUR 15,-- by postmail (sometimes postmail is fast, sometimes it´s slow)
EUR 30,-- by DPD (you should get the parcel within 3-5 working days)
EUR 40,-- by FedEx (you should get it in 1-2 working days)

Payment: in advance by bank transfer

If you want to make an order I need your VAT#. Without that number VAT must be added.

Best regards,

Marion Matzner

ROITHNER LASERTECHNIK GmbH
Wiedner Hauptstrasse 76, Top 9/1 A-1040 Vienna, Austria
Tel.: +43-1-586 52 43 - 11
Fax: +43-1-586 52 43 44
e-mail: [email protected]
http://www.roithner-laser.com

 

[IgorT]

Note: In the second quote you actually said that the LD is only going to consume 3V (output from LM317 isn't going to be 3V, more like a bit <6V), but then in the first quote you said "The power going to the LD would then be greater".

BTW: I was talking about my LD in comparison to yours.. Mine gets 3V, yours gets >5V. The power is therefor greater at the same current.. (P=U*I)


Besides, it seems i confused your circuit with the Daedal's driver circuit (from laserpointerforums), which is not using a low drop out regulator, and has a voltage drop of almost 3V in it..

Sorry for the confusion...


EDIT: In this case i would like to see the circuit you're using.. Is it posted somewhere?

 

[Phenol]

MatajumotorS,

I obtained absolutely the same beam profiles, esp the uncollimated one, especially the ragged edges using that same LED at 150mA