80mW Dorcy Blu-Ray?

[IgorT]

A good load is a bunch of leds soldered together. Read this thread: http://www.laserpointerforums.com/forums/YaBB.pl?num=1190170289

Yeah, but it only comes close to the Vf of the laser diode. Laser diodes vary in Vf among themselves. Dummy loads are good for testing current regulated drivers. You can NOT use a dummy load to test and limit the current of an unregulated driver and then expect the current to be the same, once you put the laser diode in.

I guarantee you, that the current will be different between ANY dummy load and laser diode. It will even be different among the same type of laser diodes.


If you don't care about what happens to your diode, sure go ahead. If it will work, it will be no better than direct drive with a resistor. Every time you turn it on, the power will be lower than before because of the battery voltage dropping.


If you're building a laser with an expensive or even rare diode, the driver is the last thing you want to be cheap about. At the moment, Dr_Lava's FlexDrive is the best thing for lasers, you can find.

 

[Spyderz20x6]

Thanks for the advice. I will do that.

 

[cbrian4]

Drlava sold out of the lower value flexdrives and the price is jacked to $50!!
Whats that all about? Does this mean when they're back in stock that they'll be $50?

 

[pwnstar]

so to set the current on a Lavadrive we still need a dummy load, right?
A dummy load close to the voltage drop of the laser diode?

 

[IgorT]

so to set the current on a Lavadrive we still need a dummy load, right?
A dummy load close to the voltage drop of the laser diode?

No, the Vf of the dummy load does not matter.

Any current regulator will always provide constant current regardless of the Vf of the load (if it has the right input voltage).


With the flexdrive, there is a lower limit for Vf - 2.4V.. It doesn't work under that, and goes into full current, so it's not good for IR diodes. Everything else is fine.

If you create a dummy load with a Vf higher than 2.4V, it does not have to be close to the actual Vf of the diode. Can be more, can be less, doesn't matter. The driver will always give any load just enough voltage to achieve the desired current.


Oh, and there are still $20 flexdrives, and they can be converted to the lower current range with a different trimmer i think, or maybe with a resistor.
I do not know what the $50 is about tho. And why, if it's the same board.

 

[thejunkmonger]

[quote author=pwnstar link=1210561428/15#19 date=1210956642]


Oh, and there are still $20 flexdrives, and they can be converted to the lower current range with a different trimmer i think, or maybe with a resistor.
I do not know what the $50 is about tho. And why, if it's the same board.

Seems like he ran out of boards because of all the reservations for the kryton barrel I think. I hope mine was already in the mail or already accounted for lol.

 

[IgorT]

Thanks for the advice. I will do that.

Lasers are sensitive devices, and should be treated accordingly.

A constant current driver will be able to power it at a higher current and safer at the same time. An unregulated boost driver will vary in the output depending on MANY different factors at the same time.

You would have to set the current in a way, that it would still be below the safe level with a COMPLETELY full battery.

Also, measuring the current by putting a DMM in series with the load on an unregulated boost circuit will give you a certain reading, but when you remove the DMM, the current will be HIGHER!


There are just too many factors to give general recommendations for it. It can be done safely, but the max power will be lower, and it will drop with the battery voltage. Every time you turn it on, the power will be lower than before. And if you put a better battery in one day, the current can jump and kill the diode.


A real driver will ALWAYS provide the diode with the same current (untill the batteries are empty), and the laser will always come on at the same power. You don't want to skip the most important part of the laser after the diode - the driver.

 

[daguin]

Seems like he ran out of boards because of all the reservations for the kryton barrel I think. I hope mine was already in the mail or already accounted for lol.

He posted a note saying that soon the BR range drivers would be available again and the price would come back down.

Peace,
dave

 

[Spyderz20x6]

*Releases pressure* im glad drlava will lower the price again, cause $50 is just crazy.

 

[Spyderz20x6]

Can i connect the lavadrive directly to the Dorcy circuit?

 

[Kenom]

do NOT hook it directly to the boost circuit. that's just crazy. what your wanting to do is REPLACE the driver with the lava drive.

 

[Spyderz20x6]

Ok? Why is that crazy, i don't get it?

 

[IgorT]

Why would you want to do it AT ALL?!? Read your PMs, i don't want to repeat myself, but the LavaDrive can work off the same battery, or even better (better use of the battery capacity), if you use a 3.6V battery.


Powering a boost driver from a boost circuit makes absolutelly no sense at all. If you could get it to work, you might still be endangering something, or at the very least you would lose efficiency. The unregulated Dorcy boost circuit could create a too high voltage for the LavaDrive.



I mean, why?!? It's as if you think the LavaDrive will work better off a higher voltage coming from the boost circuit?? Well, it will work worse, if at all.


Your question made me believe Dorcy was a 1xAA host, and that you want to boost 1.5V for the LavaDrive to work off. Now that would almost make sense. But if you already have to use a CR123, the LavaDrive can work directly off it.


But if this is about the battery contacts, that the original circuit provides, then you should remove all the components off the original circuit, and just solder the LavaDrive to the original circuit's battery contacts.

 

[Kenom]

see this is where you need some kind of basic understanding of electronics in order to be making lasers. Sure you can slap together a bunch of components and have it work, but this is more about getting knowledge than it is just getting a laser to work. Especially if you expect to actually understand what it is that your doing. Take the time to actually undestand what it is your doing. Do some research. Learn. You'll be better off for it.

 

[Spyderz20x6]

Oh! Now i see! I will just cut all the traces and isolate it from any boost.