Help please!

Hello!

I'm new to this forum, but i've been reading it for quite a while now. The posts were very useful, but yet i've had this problem.

I made a LM 317 driver, it's able to control the diode perfectly. After testing it out, i bought a DVD RW Super WriteMaster; took out the diode. Diode was kind of wierd... small and there was no window, plus there seemed to be IR and Red diode in one package. Anyway, i connected the red diode to my bread board, connected the circuit to the 9v battery and set the pot so the laser shined brightly, but just as much!

The problem is - laser died after a few minutes... Is it possible that 9v was too much for it? And, can it be fixed, since it still shines, just not as much? I think not, but you are the experts here It's my only diode so... hope i can get it fixed.

Thanks for your answers in advance!

(this was the driver: http://laserpointerforums.com/attac...laser-diode-driver-lm317_components01_001.jpg)

Sorry, but you are not giving us enough detail for give you a reply .....

The 9V have no importance, IF it was through the current regulator ..... that what you have to say us, is how much current you was giving to the diode

And, ofcourse, if the diode had some type of heatsink, or if you was trying it without any heatsink (cause the heat can kill them too)

Let me guess: you had the diode in an Axiz module and then turned it on. It worked nicely and then POOF it died? Happened to me sooo many times. $20 down the drain each time to see 15 seconds of red.

The DVD laser diodes will give off a lot of heat and require a bit more heatsinking than just an Axiz module can provide. If you try again, try buying one of those kits that have proper heatsinks. Make sure you use a current regulation circuit as well, not just a battery and a pot.

First off, welcome to the forum!!

Secondly the IR/Red laser diode you have is sig. less powerful then for example a LOC. Next the diode u have is an open can diode, this is why it has no window. If you made your driver correctly it should regulate the current and the diode will draw as much voltage as it needs. you have probably killed the diode, u should build a simple dummy load to test the current to your laser, pm me if you want to buy one off me. lastly if you ned a new diode you cn get them from Modwerx Home for $10.... don't forget, you need some good heat sinking for thee diodes, so you mih want to look in to that.

let me know! -Adrian

Thanks for the replyes and the nice greeting

I really suspect it was the battery. Checked some youtube videos featuring this driver, and they all used 2 AA batteries. Oh, and the diode had the original heatsink on it, plus it wasn't warm at all. And it didn't die in a blink, it shined very well and after i shut it down and re-enabled the power it just started to shine like a normal LED...

I have some other normal diodes, <1mW read lasers from DVD roms. I'll do some testing with that and see if it burns out, just instead of a dummy load. You think that'll do?

Oh, and what information did i fail to state?
-Mickey :thanks:

Edit:
Oh, forgot to mention. I have just got a DVD rom (label says nothing about a writer) that has 2 diodes in it, plus the optical sensor. Diodes look the same as any normal laser diode. Possible one's a write laser, or they are both just read lasers?

Edit 2:
oh, and they are both aimed for some kind of a cube-like prism, if that helps...

Hey rastaman,

To what current was the driver set? (which resistor did you use on the LM317)

If you made it exactly to the spec of the schematic you posted, the current would have been 250ma nothing drastic for a >16x red diode. Was the diode in a 5,6mm package, or a plastic square package?

The 9v battery was not the cause of the death, ESD or heat is what killed the diode. I doubt it was over-current. What burning speed is the drive that you bought for the project?

You could use the DVD-ROM reader 670nm diode, but you would have to set the driver to give a maximum of <50ma and be very careful with the pot when you turn it. It might be good for 5-10mw of red...?

The LM317 has a referance voltage (Vref) of 1.25V so to get the current use the equation below:

I=V/R

I=1.25 V/ 40 ohm

I=0.03125 or 31.25 mA

Though I am not entirely sure 31 mA will be enough current to get the diode lasing (threshold current). Maybe someone with reading diode experience could chime in?



Best Regards,
brtaman

Hello,

The diode was 16x speed, but in a 3mm open can package. It allso had the heat sink and i didn't find it to heat up what so ever. And, i've tested the driver circuit for a few hours at max lasing power with a write diode, it's still alive. So, i'm guessing it was the diode that was too weak. And the circuit is the same as in the schematics from my first post.

Thanks for all your helpful answers!

Edit:
And, how can i protect from ESD from now on? Is it that i just connect the 3 pins together, until the diode gets into the circuit? Plus, i don't really understand how could static kill a diode...It's not much current. Please explain!

it's not much current but diodes are just "that" sensible. The information you failed to give us is the current you set your driver to, and how did you exactly mount it (heatsink? module?)

If your driver was well constructed you could have supplied it anywhere from 7 to 25V, so definitely the 9V battery was NOT the problem.

Your main problem is that you deal with things you don't understand! Try to read this and then come back and answers the questions I just asked

It can be done - Laser driver

Yours,
Albert

it's not much current but diodes are just "that" sensible

Click to expand...

I think you mean, sensitive

BTW a dummy load is to measure the current being passed through the laser diode. A LOC (long open can) diode needs around 400-420ma of current, where as a PHR (blu-ray) needs only 100ma. Seeings that we don't know your model or its PIV graph, we can not determine the correct current level for your diode. Now if you buy a new diode from modwerx, hightechdealz... etc you will need to know the current you are using. This is where the dummy load comes in. For the popular diodes there are PIV graphs that will help you set your diode at a "safe" level of current. You need to set your driver to that "safe" level in order to stop future over driven/under driven diodes.

If done correctly, the diode will last a long time and you will know it is running at a safe level, so for future sales people will know what to expect, for example, current level, approx output power, state the diodes in.. etc

Hope that helped!! -Adrian

About ESD, it's matter of voltage, not current ..... as you probably know, LD are very sensitive about voltages, especially reverse voltage ..... matter of few volts, changes from model to model, but you can be sure that anything over 10V reverse voltage, can kill also a 60W diode bar .

Now, electrostatic, opposite to "normal" voltages that we all use everywhere, are usually from 500V to some thousands ..... if you want to have an example, do you know, when you pull off a cloth and it sparkle ? ..... in the darkness, you can also see sometimes little sparks of 1 or 2 mm ..... well, the dielectric resistance of the air is around 1000V per mm, this mean that these little sparkles that you see and that cause you just tickles, are usually around 2000V !

Ofcourse, also if you cannot see any sparkle, an isolated human body can easily accumulate few hundred of volts just by clothes friction and plastic chairs, and discharge it continuously all the times that you touch something with different potential ..... you will never notice a 100V electrostatic discharge from your body, also not just a light tickle, but for an LD, is like 20 times the maximum that he can hold , and it die without notice you :wtf:

Do you want a practical example ? ..... when i was working for an electronic company, we partecipate to an international fair, and the organization of the place had the brilliant idea to cover all the floor with high, soft, non-anti-esd synthetic moquette :tsk: ..... one of the client was asking info about a machine (the machine was working in an endless loop for demo), and the vendor, that was walking from hours on that floor, approached the machine for show to the client the features requested, and when the hand was still around 5 or 6 cm from the keyboard, SNAP, a very big and loud sparkle shorted from the hand to the keyboard (5 or 6 cm in air, means from 50.000 to 60.000 Volt ) ..... the machine gone in short circuit and literally burned up (the motor power controller got shorted too, and before the safety switches disconnects, it took fire) ..... i left you imagine the faces of all the peoples around ..... 25.000 $ of machine in smoke for a static sparkle ..... our boss was very, very angry, that day

Anyway ..... if you are good in smd working, can solder a 10 Kohm resistor and a 100nF capacitor in parallel on the diode pins (and if you use it wired, instead soldered directly to a module, you can also left them in place permanently) ..... otherwise, you can keep them "pinned" on a piece of anti-electrostatic foam, until you don't use them ..... you can find these things in any pc shops, as containers for amd processors, like this one as example (i use some of them for divide my diodes and keep them protected too) ..... they throw them away after mounting the cpu, usually, so you can ask them for one and probably they gift you it.

woha, very nice info here! +1

Yours,
Albert

Thanks for all of your answers!

I've got 3 another DVD drives, the driver circuit working and i allso connect my leg to the radiator in my room (to drain SD) every time i work.

Oh, and the current over the diode is ~242mA, it works perfectly now

When i finnish the machine i'm building, i'll put vids and pics on, for you to see and maybe get an inspiration on it! :yh:

I'm in hi-school now, doing the course of electronics and informatics, so i'm quite adept with circuitry, and especially programming. Quite a few prog-languages are better known to me than my english

Anyways, thanks again for all the great answers, you have been most helpful!

I've typed that last post too quickly. I've managed to burn 3 IR diodes and one perfect dual-layer 16x DVD diode. I used 2x AA batteries and the above driver. I have no clue wtf is wrong, i'm about to give up

And that's not good, because 2 of the people that i've got the burners from, asked me to show the laser to them.

The circuit's exactly the same as the one in my above post, 2 AA batteries in series were used, everything burns that way, and i'm out of the diodes. If i get lucky, i might get another IR diode.

best wishes,
little myself

Are you connecting the diodes with the correct polarity ? ..... IR are case positive, where instead the most part of the red ones are case negative.

Also, how you can use an LM317 driver with a 3V input ? ..... you need at least 6 / 7 V input, for use it ..... with 3 V input, the driver just don't work at all, or at maximum the red diode emit a very few light, like a led, but no laser.

Also, any picture of the driver ? ..... for try to understand if it's mounted in the right way or if there's something wrong.

Also (again ), here is a draw about how connect the LM317 in a driver circuit same as the ones that i normally use (a little bit different from ones that you can see around, but the basic connections are the same), if you cannot take pics of your one, can at least follow the wiring and see if there's something wrong (it's not a so good draw, i just made it at the moment, sorry).



With these values, you can regulate the current from 80 to 435mA, but pay attention, more you go to the high current, more the regulation become critic, and also, use a 0.5W trimmer, cause if you use the normal 100mW mini trimmers, you burn them

rastaman said:

I've typed that last post too quickly. I've managed to burn 3 IR diodes and one perfect dual-layer 16x DVD diode. I used 2x AA batteries and the above driver. I have no clue wtf is wrong, i'm about to give up

And that's not good, because 2 of the people that i've got the burners from, asked me to show the laser to them.

The circuit's exactly the same as the one in my above post, 2 AA batteries in series were used, everything burns that way, and i'm out of the diodes. If i get lucky, i might get another IR diode.

best wishes,
little myself

Click to expand...

3 Volts is not enough for the LM317 circuit in your 1st
post to regulate the current to your driver...:thinking:
It is not a Boost Driver circuit...
Correct me if I'm wrong....


Jerry

Hi Rastaman, to protect my diodes ( & any other electrical components) from blowing out from ESD, I wear an anti-ESD wrist strap. It's an elastic band that goes around your wrist & has a metal contact point that touches your skin. Attached to the strap is a long wire that you hook up to a grounded terminal, VOILA', all ESD goes down the wire to ground instead of blowing your diode. You can get them from DX for a few bucks. They also make anti-ESD mats to put at your work station that function the same way. Saved many a diode for me I'm sure !!! rob PS, if you want some IR diodes to practice with, send me a PM. If you pay the postage, I'll send you some.