HOW TO: 100+mW 405nm w/ 803T Dorcy Jr Laser

what type of batteries... i know it takes cr123a's but does the mA matter with it?... i've found 350mA, 650mA, 700mA, 850mA, 880mA, and 1000mA... which 1('s)?

these are what comes with the Dorcy Jr... I'm not sure of the current... definitely 3V though.

Has anybody had any luck fitting a rckstr driver into a dorcy. and if so, can I use the dorcy boost driver in conjunction with the rckstr driver?

shamb1s said:

Has anybody had any luck fitting a rckstr driver into a dorcy. and if so, can I use the dorcy boost driver in conjunction with the rckstr driver?

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no... that wouldn't work. the Dorcy boost driver puts out about 5.5 - 6V, for the PHR803T blu ray diode the rkcstr driver requires at least 7.5V to turn on, 9V to be safe....

I think the rkcstr driver would probably fit, the module would stick out the front some but that's fine. you'd have a voltage problem though for powering it.

even if you used 3.6V CR123 batteries, I don't think the boost circuit would output anything more than 6V, I may be wrong though as I've never tried it.

really the DrLava flexdrive driver is the best driver out there for this Dorcy application.

you could put a rkcstr driver / PHR803T in a small box or make your own host to put it all in and use a standard 9V battery (would also need a switch to turn it on and off). I'm going to make a few of these in the project boxes from RadioShack. If I'm feeling generous, I'll make another tutorial on how to do it. it's quite simple and others have made them before (I think).... I'm going to sell the boxes as a component... and the user will have to add their own power source (which I will happen to sell separately also )

I forgot to mention that I'm using a long open can red diode, sorry that its in an 803T thread. I wanted to get away from doing a complete gut of the dorcy housing, but i might have to, or at least try to take the boost driver out if it cant be used in conjunction with the rckstr driver. I would have loved to use a lava driver, but I'm going out of country for 6 months and couldn't get a lava drive before I leave in a few days. Anyways, thanks for the help in advance.

shamb1s said:

I forgot to mention that I'm using a long open can red diode, sorry that its in an 803T thread. I wanted to get away from doing a complete gut of the dorcy housing, but i might have to, or at least try to take the boost driver out if it cant be used in conjunction with the rckstr driver. I would have loved to use a lava driver, but I'm going out of country for 6 months and couldn't get a lava drive before I leave in a few days. Anyways, thanks for the help in advance.

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oh, well yeah the rkcstr driver would work after the Dorcy boost driver. I've found the boost driver in the Dorcy doesn't really go up high enough to get the full potential out of long open can red diodes, so your rkcstr driver would do just that and power it correctly.

i tried making 2 Dorcy's last night w/ a 20x long open can & 22x long open can and both instantly died with the boost driver and no resistor.... I'm thinking I need to get some 1 ohm resistors to just slow down current going at the diodes... or something like that. I thought I read that the long open cans can take the current directly from the boost driver. but in my experience... ends deadly.

toked323 said:

Just to add the Dorcy Jr has a boost circuit already good for driving blurays, you have to set current though.

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You can not set the current in an unregulated LED boost circuit. You can just limit it somewhat. And it'll still be all over the place, varying with everything from battery voltage to temperature, so you have to limit it lower, than where you want it to be.. It can be worse, than connecting a diode directly to the batteries through a resistor. And everyone will tell you not to do that. Here, there is also huge switching noise present on the output, because LEDs are tough components, which don't care much about current ripple, voltage spikes or severe overdriving. Many such boost circuits simply just blink the LED very rapidly.

I really wouldn't call that good for a laser diode.

sk8er4514 said:

oh, well yeah the rkcstr driver would work after the Dorcy boost driver. I've found the boost driver in the Dorcy doesn't really go up high enough to get the full potential out of long open can red diodes, so your rkcstr driver would do just that and power it correctly.

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A voltage booster would have to produce at least 5.5V under load on an empty battery or at least on a half empty battery, for rkcstr's driver to do anything usefull after it - for a red diode.. It would require 8.5V for a blu diode..
If the boost "driver" itself is not enough, puting a linear driver after it won't help in any way, except decrease the power further.

The only thing that would work for reds would be to put an AMC after the boost circuit. An AMC can power a red at 340mA (or less with a bypass resistor) from as little as 3.3V. But then you have to insulate the heatsink electrically from the host (and lose heatsinking), or you kill the diode.

shamb1s said:

Has anybody had any luck fitting a rckstr driver into a dorcy. and if so, can I use the dorcy boost driver in conjunction with the rckstr driver?

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Do not try that. Things can start working out of phase with eachother, and potentially cause damage to both the driver and the diode.

Spyderz20x6 said:

[quote author=shamb1s link=1214285108/60#66 date=1217983504]Has anybody had any luck fitting a rckstr driver into a dorcy. and if so, can I use the dorcy boost driver in conjunction with the rckstr driver?

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Do not try that. Things can start working out of phase with eachother, and potentially cause damage to both the driver and the diode.[/quote]


Wish i had known that a week ago, killed my diode and driver.

shamb1s said:

Wish i had known that a week ago, killed my diode and driver.

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Umm, seriously? You put rkcstr's driver after the Dorcy boost circuit, and the driver is now dead, as well as the diode?!? Are you sure about the diode?


The main problem with this is, that the Dorcy boost circuit would hardly provide enough voltage under load, for rkcstr's driver to do anything usefull after it. The other problem is, that the output from the boost circuit is not filtered in any way, because LEDs are tough devices. You would have to put a combination of caps on the boost output, to make it smoother for the driver..


The only thing that might die on rkcstr's driver is the polarity protection MOSFET. It could have been killed by the switching noise from the boost circuit. So i'm guessing you have the newest adjustable driver? In this case, you can simply bridge the MOSFET on the input, and it will work again. It's only there to protect from reverse polarity.

But i don't see why your diode would be dead, unless you did something else to it.

ok, i'll try a few things and see if i can get it working again, thanks for the help

So is it the newest adjustable rkcstr driver? If it is, it must be the MOSFET.

yeah its the newest adjustable one.

i just got in some 1 ohm resistors, it will power your red diode very well in the Dorcy Jr. let me know if you want one i'll send it for free for u shamb1s if anyone else wants one, i could throw it into an order if you buy something from me... like a [link=http://www.hightechdealz.com/index.php?main_page=product_info&products_id=48]diode[/link]!

apparently i did something wrong, and i actually burned up the voltage booster on the dorcy jr itself, i hooked the LED back up and it very dim, and if I measure the voltage off the booster it peaks about 2V and then rapidly drops down to only .7V. Being this is my first Laser project I think I'm just gonna get a couple CR123 battery holders and throw it all in a hobby box, see what I get. My only questions with that is will I need to place a diode in the mix with my batteries like you do with the lava drivers when using more than one battery. I'm hoping 2 CR123's will get the job done. They are the 3.6V 900mAh rechargeables. Thanks in advance guys.