stonetek 16x sony closed can

Sorry I missed your post Morgan. I was aware that current regulated drivers varied the voltage in order to achieve the set current. So say you have it set to 100mA and you have 9V on the input. You could drive a BR diode, and the driver would adjust to around 5V. Or you could drive a red diode and the voltage would adjust to around 2V , in order to stay at 100mA current in both cases.

That's how I always thought it worked anyway

Regards,

Adam

diachi said:

Sorry I missed your post Morgan. I was aware that current regulated drivers varied the voltage in order to achieve the set current. So say you have it set to 100mA and you have 9V on the input. You could drive a BR diode, and the driver would adjust to around 5V. Or you could drive a red diode and the voltage would adjust to around 2V , in order to stay at 100mA current in both cases.

That's how I always thought it worked anyway

Regards,

Adam

Click to expand...

Now that's an interesting way of looking at it. Couldn't give you an answer either way on that. If it DID work that way then the driver will get damn hot when you hooked up the red! lol

Yes, I light matches at a pinpoint. I guess this debate is about personal preference and known limits. I may have been being over cautious when I built mine but it did what I required of it. I simply didn't want rajkosta to hook up his, (potentially one and only), diode to instantly vapourise it.

I think there is a need for those data sheets compiled a while ago. I'll go and have a hunt for them..........

M

You need around an extra 3-4V FOR the driver. So whatever voltage your diode needs, you want to give the driver 3-4V extra for the driver dropout. I'm not sure exactly how the driver works, but I think that's the principle behind it

Just a quick thing, BEFORE you hook up your diode SHORT the two output pins on the driver,this will discharge the filter capacitor. If you don't do this your diode will die instantly.

Regards,

Adam

Found it!

I knew it was around somewhere....

http://laserpointerforums.com/laser_pointer_forums_3/forum/showthread.php?t=26417&highlight=data

This link has masses of info in it rajkosta. These results tables were done by well respected and experienced members. You'll find a graph for your Senkat diode, (as they have been known), in the Dr.Lava's graphs bit. (It's the hand drawn one). It suggests anything over 400mA will just create more heat and therefore seems to be the absolute upper useful limit.

It should also give you some idea of where you might want to go next for your next build. Long Open Can, PHR-803, KES-400, etc

Enjoy!

M

Quote "Just a quick thing, BEFORE you hook up your diode SHORT the two output pins on the driver,this will discharge the filter capacitor. If you don't do this your diode will die instantly."
Good point Adam. I get the feeling some of the basics are not being passed on as older members move on or the info has been lost in the move. I'm guilty too! I'm sure it can all be recovered using the search button.

Morgan said:

Found it!

I knew it was around somewhere....

http://laserpointerforums.com/laser_pointer_forums_3/forum/showthread.php?t=26417&highlight=data

This link has masses of info in it rajkosta. These results tables were done by well respected and experienced members. You'll find a graph for your Senkat diode, (as they have been known), in the Dr.Lava's graphs bit. (It's the hand drawn one). It suggests anything over 400mA will just create more heat and therefore seems to be the absolute upper useful limit.

It should also give you some idea of where you might want to go next for your next build. Long Open Can, PHR-803, KES-400, etc

Enjoy!

M

Quote "Just a quick thing, BEFORE you hook up your diode SHORT the two output pins on the driver,this will discharge the filter capacitor. If you don't do this your diode will die instantly."
Good point Adam. I get the feeling some of the basics are not being passed on as older members move on or the info has been lost in the move. I'm guilty too! I'm sure it can all be recovered using the search button.

Click to expand...

Yeah it's a shame some of the great info that has been lost due to members moving on, and the whole forum move

i have a LOC, it does nothing...i must have ruined it, or it was ruined already while in the 112D, check my other thread for pics, its really weak, weaker than the 5mW i got with the aixiz case, while outputting searing heat

ultimately, all of the components will go into a plastic gun, are you sure i cant use my 4 batteries ? it seems to go up to 300mA fine with them

by looking at the graphs...it seems the the diode uses as much voltage as it needs...which is usually 2-2.5V
the driving circuit subtracts 2V out of the input voltage, so i will have 2.8V available voltage to the diode
it seems to me that all the excess voltage will go into heat of the LM317 metal part, so less voltage is better, if its enough
MORE voltage than required shouldnt affect the diode, right ? the output power and heat should depend solely on the amperage ?

If your enclosure is the benchmark for the size, then there are other battery formats to think about. Do a search on the forum for batteries and you'll see that there are more than a few options to get 6V plus out of the same space for a single AA! Different drivers will also give you more options. Flexdrives, LavaDrives, RCKSTR drives...

Yes, MORE voltage shouldn't affect the diode but losing all that heat in a plastic gun could present problems. I think you should be confident to do some experimenting and find what power you want to set your diode to first then you can cut back on the IN power to match your OUT power. You might find that 200mA will do just what you want it to. And it might do it for twice as long! It's all a matter of balance.

I hope that's helpful.

M

i had my first LOC mounted into a plastic toy Uzi, with no heatsink. it was running at 450Ma lol, but with a very short duty cycle. just long enough to light a cigarette. that diode died due to a backflash but i never had ANY problems with it as long as you dont run it for very long at all. but 2-300Ma will provide you with a long lifespan at the cost of burning power, and beam visibility. 2x CR2 batteries would be PERFECT for this application. their small and provide an EVEN 6 volts "except the rechargable ones, just over 6volts" and plenty of Ma. those r what i use anyways. chose them specificly because you should always have at least 3volts going to the driver, and diode, for a total of 6, thats about the minimum voltage that will still allow the LM317 to function at the FULL capacity of your laser diode.

The last Red LD I tested for StoneTek was a 1239JL. At 400 mA I got 245 mW .. I doesnt go higher than that. The graph shows the first knee at 350 mA with 220 mW of output. That point is the knee I found and you should probably back off a little from that. #00 mA should give you a "safe" 200 Mw. This is assuming you have the 1239JL 16x diode.

mIKE

i will get it soon hopefully (ordered the same day as DX aixiz housing and housing arrived today)
because of the 5Ohm static limiting resistor i cant seem to get any more than 270mA at the diode pins (measuring with only multimeter connected), but that might be because of a little added resistance of the multimeter...
resistance should only LIMIT current, not make it constantly a bit lower, right ?
so when i reach the 270mA mark on my multimeter it will be 270mA on the diode too right ?

yes it is that 1239JL diode, or thats what it says i ordered...

i can put LOTS of random bits of metal inside the gun...its going to be in the main chamber part, its not going to be as a laser sight, the 5 1.2V batteries fit fine into the handle, i even have a charger for them installed there (one of the simple ones, with just a lm317 and a resistor that limits current to 10% of battery capacity, takes 10 hours to charge)

if i solder the metal parts one to another, will they act as a heatsink as one metal unit ?
if so, then that should be enough cooling for 2 minute cycles

no dont do that... it could lead to shorts. any heatsink will do... if your above the 400Ma mark... i'd go with a larger jayrob type heatsink.

if your driver stops at 270Ma... maybe there isnt enough Ma in your batteries...but i doubt it. it should read whatever the LM317 is capable of putting out "or whatever you set it to"' when hooked up to the right power source.

if i missunderstood let me know.

Dark

it stops at 270mA either way, doesnt depend if its hooked to batteries or wall power

rajkosto said:

it stops at 270mA either way, doesnt depend if its hooked to batteries or wall power

Click to expand...

The reason you can't go above 270mA is due to the design of the LM317. It is a current limiting component, by using 5 ohm you limit current to 250ma.

The 317 has a reference voltage of 1.25v. In order to determine current output the following equation is used:


I=U/R

If R=5 ohm.......then I=1.25/5 I=250ma

If R=4 ohm....then I=1.25/4 I=312.25ma

thought so, so i can, for testing, just short out the 5ohm resistor (dont have any 4ohm ones atm) and use ONLY the potentiometer, which will be dangerous (huge current if i overdo it), but should work

rajkosto said:

thought so, so i can, for testing, just short out the 5ohm resistor (dont have any 4ohm ones atm) and use ONLY the potentiometer, which will be dangerous (huge current if i overdo it), but should work

Click to expand...

Hey, I would not recommend you running the driver without the resistors. Pots are finicky things and are quite often not linear at the end, the resistance jumps and you burn your diode.

You can always try a combination of resistors wired parallel.

R= 1 / ((1/r1)+(1/r2)+(1/r3)) etc.

http://www.1728.com/resistrs.htm

Here is an on-line calculator you can use.


Or if you have 2-ohm resistors connect them in series and you have 4 ohms.



Thanks
brtaman

i have 2 of the 5ohm
i will just connect them parallel then
give me 2.5ohm that is 500mA limit