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Thor
25mW Classic Wicked Laser

Joined: 30 Jan 2008
Posts: 26

Posted: 1/30/08, 10:02 PM Post subject: Where's th

I think I'm losing my mind... I just posted this a bit ago, but can't even find the thread now... Anyway, I ordered a 650nm 10mW 12mmx30 mm as per specs from the famed "flashlight burning laser" (ordered from mfgcn) along with a 200mW diode just in case the DVD one didn't work. I dismantled the 10mW, leaving the "driver" in place, and added my 200mW diode. I got a bright red beam, but no heat at all. I tried focusing different ways, but nothing. I even used an IR heat sensor plugged into my Fluke meter to measure heat, but nothing. Then I hooked it directly to the batteries without the "driver" that came with it (it was just a tiny icb) and got the same thing. Bright, vibrant laser, but no heat at all. I'm only hooking up the positive and negative (not the 3rd leg that shows an "unused"). What could I be doing wrong? I've tried different battery types: 2 AA's (~2.7 v output), 2 "hearing aid" batteries ~ 3.2v output, 2 D's, etc. Same thing. Nice laser, no heat. Any ideas what I could be doing wrong? I saw elsewhere that 2 lens' were required, but the 650nm 12x13 chassis only has one. It does have a little "twist-to-focus" threaded insert though. Any help would be much appreciated. Thanks!

Pfin
4.99mW Green Laser Toy

Joined: 28 Jan 2008
Posts: 4

Posted: 1/31/08, 12:36 AM Post subject:

I got one match to light off my diode than just a laser poitner. I either overpowered it or shorted it.

MB4004
Elite Laser

Joined: 28 Sep 2007
Posts: 163
Picture(s): 1

Posted: 1/31/08, 7:38 AM Post subject:

Thats pretty unusual. I tried to measure mine with an IR heat gun and it didn't work so I wouldn't go off of that. But your sure that its collimated correctly?

thecheat
Wicked Lasers God

Joined: 13 Jan 2006
Posts: 3306
Picture(s): 213
Movie(s): 12

Posted: 1/31/08, 8:05 AM Post subject:

I think it may be the driver board. I think it's meant for 10mW not 200mW! you'll have to solder the leads directly onto the diode... PLEASE use a resistor! (on the positive lead) _________________ I'm building a JET ENGINE! check my site HERE!

Thor
25mW Classic Wicked Laser

Joined: 30 Jan 2008
Posts: 26

Posted: 1/31/08, 9:46 AM Post subject:

Pfin wrote:

I got one match to light off my diode than just a laser poitner.

I either overpowered it or shorted it.

I don't understand how that works - In this case, I was very careful not to discharge any static, etc - I can see frying it, but how would it "burn" the first time, and still be full and bright the second time and not burn? I don't see how that could happen (but that's why I'm here;)

Thor
25mW Classic Wicked Laser

Joined: 30 Jan 2008
Posts: 26

Posted: 1/31/08, 9:50 AM Post subject:

MB4004 wrote:

Thats pretty unusual. I tried to measure mine with an IR heat gun and it didn't work so I wouldn't go off of that. But your sure that its collimated correctly?

Hey -

Well, the IR measures heat from a light bulb, a lit match, and my wood burning stove, so I thought I would give it a shot. I also used the "Bubba" method of using my finger for a heat test (yes, I know) and nothing. It's almost as if the diode is not really a 200mW diode (though the package said so).

I'm using the single lens that came in the 650nm 12mmx30mm chassis, and it "seems" to focusing fine (if that's what you mean by collimated). Now, I did notice that when I focused it down to a tiny pin-point dot, it looked like it has a little "line" through it -- like a tiny little "Saturn" if you will. But not when it's "normal" at a couple of mm...

t

Thor
25mW Classic Wicked Laser

Joined: 30 Jan 2008
Posts: 26

Posted: 1/31/08, 9:57 AM Post subject:

thecheat wrote:

I think it may be the driver board. I think it's meant for 10mW not 200mW!

you'll have to solder the leads directly onto the diode... PLEASE use a resistor! (on the positive lead)

Thanks for the feedback -- I was thinking that too - but as I said in the OP, I've gone "direct" to the diode from the batteries and the same thing happened. Nice, bright laser, but no heat.

What spec resistor? Is is possible that the laser "burned out" in regard to generating heat but not light as per the above post? I don't understand that... But I'll try anything at this point.

Deadeye
Phoenix Laser

Joined: 05 Mar 2007
Posts: 83
Location: Europe, Germany

Posted: 1/31/08, 12:09 PM Post subject:

I think thecheat is right on that driver board thing. Simple driver boards are usually constant current supplies, so your new diode gets the same current as the previous 10mW one. That of course is not enough. But please be very carefully and do not connect the diode directly to the batteries as in most cases it'll lead to an instant death. There are diodes that can stand that high voltage but most do not, even not the high powered ones. But be also careful of what you expect. A 200mW diode is not a killer and it'll almost be impossible to feel any heat of a red laser unless it's extremely powerful und very well focussed. You'll only be able to burn something on very short distances and with an extremely focussed dot. Try adjusting the collimation to a normal beam and use a magnifying glass for example. But don't expect too much. There won't be fire death or destruction Edit: you should also be aware of the current you can apply to the diode. Then I recommend a multimeter and try to adjust the driver board to a higher current. But you should be able to measure the current as any over current will lead to the diode death. Without proper measuring and knowing of the diode's specs your are very likely to kill it while trying.

Thor
25mW Classic Wicked Laser

Joined: 30 Jan 2008
Posts: 26

Posted: 1/31/08, 12:14 PM Post subject:

Deadeye wrote:

...
But be also careful of what you expect. A 200mW diode is not a killer and it'll almost be impossible to feel any heat of a red laser unless it's extremely powerful und very well focussed. You'll only be able to burn something on very short distances and with an extremely focussed dot. Try adjusting the collimation to a normal beam and use a magnifying glass for example. But don't expect too much. There won't be fire death or destruction Wink

Thanks Deadeye -- I'm not hoping to make the cat burst into flame -- I'm just trying to light a match as I've seen all over the place. Research I've done alludes to even 75mW diodes being able to do so...

So, I've tried the "direct to battery" connection, and it doesn't fry the diode - but I get no heat. I'll try some new lithium batteries today and such... Any recommendation on what rating resistor to put on the positive in the absence of making a new "driver"?

thanks
t

Deadeye
Phoenix Laser

Joined: 05 Mar 2007
Posts: 83
Location: Europe, Germany

Posted: 1/31/08, 12:36 PM Post subject:

Ok, lighting a match is sometimes very easy, sometimes quite hard or even impossible. First use a dark coloured match. White won't even smoke even with a 200mW red laser. If necessary you can try painting it black using a black sharpie. You'll also need a good lense that focusses the beam down to a really tiny dot. My pulsar also doesn't ignite matches very well and only with fresh charged batteries and the help of a magnifying glass and even then not in all cases. For example I have some bigger matches here that just won't ignite, no matter how black i paint them... all they ever do is smoke a little bit. Considering the resistor I can't help you. It's very different and depends on the diode and the source voltage. I powered a red 5mW diode once with a 10 Ohms resistor and connected it directly to batteries which were putting out around 2,8V under load. You'll need to measure it. If I am measuring a diode i connect it to my power supply and start to raise the voltage from zero volts slowly while monitoring the current in milliamps at the same time. After I got the diodes operating voltage and current I calculate the resistor necessary to operate it properly and try to find a matching one in my toolbox.

ghost
Elite Laser

Joined: 13 Jul 2007
Posts: 192
Picture(s): 4

Posted: 1/31/08, 12:58 PM Post subject:

I also got the same board am I'm about to try the same thing with a DVD-RW diode. I was planning on soldering it to the driver board. Before I do that, however, I'm going to unsolder the current diode and use my multimeter to test the driver's voltage and amps. I think it should be under 3V and 200ma to power the diode correctly. Why don't you try doing this? This will tell you if the driver is powering the diode well... _________________

Thor
25mW Classic Wicked Laser

Joined: 30 Jan 2008
Posts: 26

Posted: 1/31/08, 1:12 PM Post subject:

Deadeye/ghost -- thanks for the input. I'll try the "black match" trick and see what happens -- I'll also get a better "test mount" so that I can better focus the beam. Maybe a good power supply is in order as well so that I can test. Ghost, the driver puts out 2.7v as do the batteries (no difference between the output of the driver and the batteries direct) however, I don't know what the amps are... Maybe my other mulitmeter will help with that... I guess I should really test it with the 6 aa's that go in my son's Lego robot-- that's ultimately where we'll mount and control this thing. At THAT point, the cat is in danger (jk) ((maybe)) t

ghost
Elite Laser

Joined: 13 Jul 2007
Posts: 192
Picture(s): 4

Posted: 1/31/08, 1:21 PM Post subject:

Okay. The voltage sounds good, and according to the site, it can put out about 150ma. I think at full power a 200mw diode runs at 200ma. But running it at 150ma will probably give you no duty cycle and a much longer life for the diode. So the driver sounds okay. Don't hook those 6 AA's up to the diode directly! That's 9V! It will fry the diode instantly. But you probably meant hook the 9V to the driver board which will lower it to 2.7V, right? _________________

Thor
25mW Classic Wicked Laser

Joined: 30 Jan 2008
Posts: 26

Posted: 1/31/08, 1:24 PM Post subject:

Actually, at the time of posting, I didn't mean that, as I was working on something else and not thinking clearly But yes, that's what I mean NOW. Thanks. I'll head to the hardware store at lunch and see what kind of power supply selection they have. I need big magnets for another project anyway t

Thor
25mW Classic Wicked Laser

Joined: 30 Jan 2008
Posts: 26

Posted: 1/31/08, 5:11 PM Post subject:

OK - here's where I am... I've got a 3 watt, 300ma power supply. We've already established that the current "driver" does not change the input voltage -- well, if it does, it doesn't change it from 3 to anything. 3 in = 3 out. Even so, it certainly could be limiting the amerage for the "original" diode -- but that wouldn't be to "protect" it -- if the volts are right, the diode will only draw the amperage it needs, up to the rated amperage of the power supply. Any amperage limit would be to simply keep the 10mW diode from blinding someone, but not to keep it from getting "fried." Unless, of course, what it does is keep the voltage at 2.7 no matter what the input is -- that would make some sense. But, in this case, since I know the output==input (~3v) why does it matter? Therefore, I don't see why I need a resistor between my 3v 300mA power supply and the diode. If the voltage is right, and the diode will only draw the amerage it can, what does the resister do? I guess I'll find out, because I'm going to go ahead and solder the 200mW diode directly to the DC 3v 300mA power supply and see what happens. Is that a stupid thing to do? If so, why? I guess the 2 questions I'm looking answers to are: 1) Why the resister given the above - what exactly does it do in this case? (other than resist 2) Is it possible that what another post said is true: that it "burned" the first time, but not any more after that even if the laser was strong and bright? I guess there's only one way for me to find out. "Here, kitty kitty" t

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