Red DIY DVD laser burner.

yeah. that's what I pretty much said. I don't trust aixiz. I would rather wait a few weeks to get my modules from Dealextreme.com instead of the shabby business practices of Aixiz. I remember waiting a few months for the glass replacement lenses that senkat bought as a possible increase of optics in the aixiz module. I don't think that $$50 or whatever is a good price for any diode unless it is going to put out over 200mw cw. I know i'm dreaming and there is no way we are going to see a diode for under $200 with Cw ratings that high but one can hope.

I'm waiting on the pushed results of the Phazer diode and will always have a staple of GB diodes available from the always reliable Senkat. To bad he got screwed so badly on that order of diodes from the first retailer. I think we should all go to wherever it is this man is and paint him black and turn all his diodes on him! he'll look like swiss cheese by the time we get done with him!!!

Yeah your video was awesome Kenom. Also the Dorcy you modded into a laser looks as if it were factory made.

I've actually had to modify the way I deal with these.  Since the circuit no longer puts out a stable 350ma that I'm seeing I've decided to take the current down a bit.  Now since there's not much room in teh head of the dorcy I had to get pretty creative to make this work.  Here are some pictures detailing what I had to do in order to make this work... I got lucky using 2 10ohm resistors took my current down to about 270ma



My positive and negative needs to line up with the drivers coming from the battery compartment.  as you can see the hole in teh center is positive and the ring around the outside is negative.  So whatever I made needed to fit into those places.



My resistors and capacitor soldered directly to the pins on my diode.  I used the spring that came with the light board up top to provide a little spring in the head. Oh and as you can see I did some "fins" on the heatsink the way I've wanted. TO bad it's not more precise using a dremel and a cutter head. I'd like to see smaller fins for increased airflow.



Mounted in the head it lines right up with the center hole and the resistors act as teh negative which ground to the barrel and fits against the ring for my negative.

update.... donno what I did or what's the source of the "whine" but now when I power on this laser it has a really high pitched whine. Kinda like what you used to hear from old t.v. sets. when it was set on a channel that had a salt and pepper fight. (static)

Did you mention there was a boost circuit under the plastic? If so, the likely cause is inductor ring. Consider that the inductors are coils of wire that have an oscillating electric passing through them. Depending on the frequency, the changing magnetic field can also cause harmonics in the audible range.

Kenom said:

update.... donno what I did or what's the source of the "whine" but now when I power on this laser it has a really high pitched whine.  Kinda like what you used to hear from old t.v. sets. when it was set on a channel that had a salt and pepper fight. (static)

Click to expand...

yeah the driver looks like this.

There would have to be something loose in the coil to make sound. The coil I trashed today looked well made of small wire and tight. Unusual that yours can be heard.

Mike

Some of the inductors are better made than others.

I have heard a fair number of the small LED flashlight driver boards squeal. A lot depends on the driver frequency, for the ones running in the MHz or 100+ kHz range, it is more rare to hear them. For those in the 10's of kHZ range, the harmonics can sometimes be heard, especially if the circuit is modified and the inductor is driven into saturation.

BTW, Kenom, that could also introduce some high freq noise which may not be nice for the LD. It would be easy to see if you hook up a scope - do you have one handy?

You may also be able to make the circuit more efficient by changing the 0.33ohm sense resistor with a larger one and cut your dropping resistors. (Probably want to experiment with a dummy load first )

Paul

unfortunetly I've not got a scope nor the skill to figure out what is going on. I would be more than happy to send this to you to let you fiddle with it and see if you can get a potentiometer into the driver for instant modification of current and whatnot.

I just looked up the flashlight on the Dorcy web site.  I see that this is a 1xCR123 boost driver for a Luxeon.  Unfortunately, it is designed to boost the voltage from about 2.8-3V to about 3.5-3.8V to drive the Luxeon.  The GB LD is wanting around 2.8V in its "sweet zone".  

To get good efficiency and current regulation, a buck-boost converter would be required.  

The exisiting board does not look like a good candidate for this.  (I was thinking it was boosting from 1xAA.)  It is often very difficult (if not impossible) to identify the component (IC1) from its top mark.  ID'ing that component and getting the data sheet would be a huge leap in planning a circuit mod.

Paul

I don't have a schematic on the Dorcy circuit, but *something* is limiting the current to about 280ma when using a GB diode, which brings the voltage down too.
I don't know if that's just a resistor doing that, or if it's got some active current regulation.
I'll put mine on a scope and see what kind of ripple there is.

boy I donno how your getting that low. Mine goes upwards to 390ma with a GB diode and stable at 350ma usually. I'm curious to see what you get on the scope.. I really wish I had a scope and the means to use it.
I've got one now that it consistently putting out 390ma on fresh batteries and it's toasted every single diode I've put on it until I put resistors in line.

Are you using 3.6V batteries? I'm using a Duracell 3.0V. It says CR123, but the fine print says CR17345, which is really a CR123A. These have some current limiting. My battery is currently at 2.8V (been busy).

Anyway, with no load (totally unrealistic), the Dorcy circuit is putting out 5.14V, with 0.2V of sawtooth ripple, at a surprisingly low frequency of about 20Hz.
As the load goes up, the voltage goes down, the ripple remains constant at 0.2V, and the frequency goes up.
With my open-can diode across it, the voltage is down to 3.07, but the ripple frequency is up to 25KHz.
So there must be some loads where the converter is running at audible frequencies, or harmonics of audible frequencies.

nope the batteries I'm using are the one's that come with the light. I have modified it a bit as you can see by adding 2 10 ohm resistors and a 47uf 16v capacitor in the circuit (see pics above)

Fresh Data --
Dorcy Jr with 3.6volt cell

Using a Tecktronix scope and HP Freq counter ---

0.10 vac P/P at 142 KHz across the LED. This riding on 3.27 VDC. I couldn't hear a thing.


Mike

I'm sure it's coming from the capacitor I put on there.