MXDL Over 300mW! (LPM Reading Video pg. 2)

WOW, i think you have a winner there, that must be a really sturdy diode since it was being connected straight to the bateries, and i heard that lithiums have quite a big start up spike.

...lazer... ;D ;D ;D

nice one jayrob, and:
wow to gazoo, for spotting this. You just saved my diode gazoo, I was gonna do senkat diode with AMC 7135 and a 33ohm parallel resistor, only in an MXDL case, and the washer would be connected to the module, and the case. THat would have fried my diode for sure! Thanks gazoo

And yes i admit I was dead wrong, it is better to ge tto the bottom of fishy things, if jay didnt, he might have killed his diode!!

and if 35 is good, ill go for it once my new debit card arrives!

thanks,

amk

wooooooolazer said:

WOW, i think  you have a winner there, that must be a really sturdy diode since it was being connected straight to the bateries, and i heard that lithiums have quite a big start up spike.

...lazer... ;D ;D ;D

Click to expand...

These diodes are so awesome...I am definitely going to set up the MXDL (heatsinked) with a HOT open can. I mean, 250mW or better.
Gazoo, I have calculated that in a DDL driver, a 3.3 ohm resistor would supply about 375mA. Or, a 3.0 ohm resistor would put out around 416mA. Hmmm, the latter sounds familiar! Anyway, these are 1/2 watt resistors that are available at this resistance. 1/2 watt is ok as long as I don't go over 500mA correct? Am I thinking correctly about this?
Jay

Jay,
To calculate the wattage of the resister needed take the reference voltage and multiply it times the current. The reference voltage of the 317 is 1.25 volts. 1.25 X .400 = .5 watts.

So you can run with the same current as your ice box laser. If you want to go higher then you might as well switch to 1 watt resistors.. But as you know driving the open can with 400ma's makes for a very impressive laser.

Thanks Gazoo....Hmmm, the 3 ohm resistor should put out right around 416mA, give or take a few mA. The 1 watt resistors listed at Digikey, are not available at this resistance, but the 1/2 watt ones are. I guess I'll try it to see if it will work out ok. It will be easy enough to change out if it doesn't do what I want it to... You know, I think I will go ahead and turn out another heatsink and drill it out to fit my extra Meredith module. I'll just put a set screw on the side of the heatsink. This way, I can easily try different lenses. (your power of suggestion is taking over) Ha Ha! I may get this heatsinked MXDL close to 300mW after all! Well, my Ice Box measures 287.9mW with the Meredith glass lens @ 416mA. But hey, maybe the other open can diode that I have sitting on the shelf will be a little 'hotter'! We shall see...
Jay

Sticking to the plan...Just mounted a brand new open can diode into a Meredith module with a glass lens. I made a new heatsink to fit the Meredith module. (Notice the small set screw)

The DDL driver will have a 3.0 ohm resistor and should put out around 416mA. With the glass lens, it should be close to 300mW. I will have the silicon diode as well as the cap mounted onto the MXDL circuit board instead of directly to the LD. We know that the open can diodes are very sturdy, so with short duty cycles and this heatsink, I am not afraid to put 416mA into it! Just waiting on the 3.0 ohm resistor. More pictures and power measurements to follow...
Jay

Update: This is going to be a nice set up with the glass Meredith! I just did an initial test to make sure the diode works. Using the test driver I made with the AMC7135 which is running at 338mA, I got a steady reading of 237mW and a peak of 243.7mW! Very happy with this so far! Man, this makes me wonder if I should just use the 3.3 ohm resistor instead of the 3.0 ohm. The 3.3 ohm resistor should put the DDL driver up to around 375mA. Decisions, decisions...

Well you could always try it with 3.3 ohms. I am not sure how much of a difference .3 ohms will make. I do know you are determined to have a 300mw flashlight type laser...and I know you will get there...

Your machining skills do impress me too.

Gazoo said:

Well you could always try it with 3.3 ohms. I am not sure how much of a difference .3 ohms will make. I do know you are determined to have a 300mw flashlight type laser...and I know you will get there...

Your machining skills do impress me too.

Click to expand...

You know...the driver/MXDL little round circuit board is going to be very crowded with the silicon diode and the cap on there. If I try the 3.3 ohm resistor first, it will probably just make me want to see what the 3.0 resistor will do! So, with this reasoning, I better just go with the inevitable! Thanks for that compliment Gazoo. I'm really not much of a machinist, I have a small Atlas 6" (Craftsman) lathe. For small stuff like this, I can fake it alright though...
Jay

Phew! You know... I was thinking of the logic of when Gazoo said that the 1N400X diode was throwing the regulation off... and I couldn't possibly think of a reason whatsoever! :-/

Obviously, now, the reason is a short-circuit regulation

On the other hand, now I, too, have an open-can on the way to me ;D

Jay, that was a great video that will probably result in a shortage in the supply of DVD burners soon enough

Thanx Gazoo for your excellent ability at guiding people to a solution on here. It helped stop my mind from racing like a madman!

--DDL

when extracting a diode from a pioneer 112D, is there a little PCB thing soldered to the back? how hard is it to remove that? will I be able to get a good diode on my first try?

On the other hand, now I, too, have an open-can on the way to me

Jay, that was a great video that will probably result in a shortage in the supply of DVD burners soon enough

Click to expand...

Hi DDL, I was wondering if you saw this thread...This open can diode must be the 'phasor' diode that we have all been hoping for!

when extracting a diode from a pioneer 112D, is there a little PCB thing soldered to the back? how hard is it to remove that? will I be able to get a good diode on my first try?

Click to expand...

amk, yes if your careful, you will get it on the first try. Not sure how Gazoo is treating his diodes, but I have been 'clipping' the thin film type pcb material away from the pins. Using small wire snips, I start around the edges, then, I found that clipping straight down along side the pins, one at a time until I can clip all of the pins clean. (except for a little solder) For me, the tricky part, is holding the open can in my fingers without touching the exposed delicate areas...
Jay

I get my soldering iron nice and hot, then I apply it to the mylar. Using a small flathead jewelers screwdriver, I pry up from underneath the mylar at the same time I am heating it up and it comes off.

I do not hold it in my hands when I do this. I use a vise gently gripped to the diode. The vice also helps to heatsink the diode while removing the mylar. Also before mounting the diode I test it quickly with a pair if nimh batteries. ;D

One more thing...use an anti-static grounding wrist strap and mat.

Daedal said:

On the other hand, now I, too, have an open-can on the way to me ;D
--DDL

Click to expand...

Daedal,
I think you will find as I did, the open can is electrically and optically sturdier than the phasor diode. Of course I never did have a phasor to play with so I can only compare to your review of it. But at least I got a good half hour out of my open can running at 600ma's and putting out 350mw's... ;D With a TEC of course.

I believe the safe current to run these at is 350ma's...400ma's might be pushing it just a bit but what the hell...lol. I do think the beam spec of the sony diode are a bit tighter, and it seems to be a bit better burner with the same output. But it has been awhile since I have compared them and like Jay, I have used three different types of lenses. I will be very interested to know what you think of the open can.

I just built a MXDL flashlight based laser with an open can laser diode and similar heatsink.  The MXDL flashlight already had a 3 ohm, 1 Watt  resistor used for current limiting to the LED so I just used that with the LM317.  416mA on the money.  I'm using a standard Aixiz module with the plastic lens and get 280mW of output.

I didn't know those were 3 ohm resistors! I guess I'll save them now, instead of thrwoing them away! Hey nice job with the MXDL. I'll let you know shortly what the power is with the Meredith glass lens. What DVD was your open can from?
Jay

This whole problem was one I had recently as well. I had a Senkat Diode, DDL circuit running around 267 mA. Stuck it in my pocket and I went to show a friend what it could do, and it was popping holes in black plastic spoons REALLY quick, and basically cutting slices in them as I moved the beam around. Even I was impressed. I took it home and my "Ball of components wrapped in tape" inside the head had came loose when I adjusted the lens, and 2 contacts were touching, giving it 420 mA. The thing was cooking, luckily I use a 30sec on/off duty cycle and it's heatsinked. Glad you solved yours.