Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

200mW red laser dorcy mod...need quick info...(:






Joined
Feb 5, 2008
Messages
6,252
Points
83
Just forget the Kipkay explanations, he can't do anything right, and explain it even less.

As has been explained, all you need besides the LM317 chip is TWO components, one resistor and one capacitor.
Nothing else. As simple as it gets, no need to seek for more.

Calculate the resistance by
1.25 / Current_in_mA = Resistance in OHMs.

You will want a nice 380mA though your diode, 3.3 ohm.
 
Joined
Mar 30, 2010
Messages
67
Points
0
Ok GOOD ! :)
Since you mentioned it, Kipaky gives no DETAILS AT ALL in his vids...bets are hey just copies other's work...

I got the 3.3 ohm resistor :)

Can I use any capacitor and can I get the LM317 chip at my local Radio Shack ???
And is the LM317 chip a voltage regulator?

And can you give me an idea how this thing will be wired up ? Even a picture close enough too waht it will look like would pe perfect :)
I've worked with circuit before but not with laser or drivers :)
 
Last edited:
Joined
Feb 5, 2008
Messages
6,252
Points
83
Sorry ..... you mean amperes, not milliamperes, right ?

1.25 / Current_in_A = Resistance in OHMs.
Exactly, sorry, my bad, thanks for correction.
Ok GOOD ! :)
Since you mentioned it, Kipaky gives no DETAILS AT ALL in his vids...bets are hey just copies other's work...

I got the 3.3 ohm resistor :)

Can I use any capacitor and can I get the LM317 chip at my local Radio Shack ???
And is the LM317 chip a voltage regulator?

And can you give me an idea how this thing will be wired up ? Even a picture close enough too waht it will look like would pe perfect :)
I've worked with circuit before but not with laser or drivers :)
Any capacitor will work nicely, as long as it's in some uF range (nF is not good enough).
Wiring it up is grass roots basics.

You connect +IN to the right pin of LM. You connect resistor to middle and left pin. Connect left pin to +Capacitor also.
You connect +LD to +CAP, and -LD to -CAP.
Connect -CAP directly to battery.

All done partner, fire her up and rock 'n' roll.

Sorry for being lazy about drawing a schematic, plenty can be found on this forum.
 
Joined
Mar 30, 2010
Messages
67
Points
0
ok just to be sure...I'll need:

- 3.3 ohm resistor (http://rocky.digikey.com/weblib/YAGEO/Web Photo/CFR-50JB-3R3.jpg)
- capacitor (The side with the stripe is positive ?)
- LM317 regulator (Can I get it at my local Radio Shack ?)

And what is my power source going to be ??? 3V...9V...6V...

And Eudaimonium, I'll send you a SIMPLE drawing I made of what you told me to do and I could have drawn a schematic but I wanted you to understand my drawing.
 
Last edited:

HIMNL9

0
Joined
May 26, 2009
Messages
5,318
Points
0
- capacitor (The side with the stripe is positive ?)

If you are referring to normal cylindric electrolitic capacitors, the stripe painted on their body is usually negative

attachment.php


As you can see ..... all them have a "minus" sign printed in the strip, and actually 99% of them follows this standard.

Only some very old type of capacitor, or some rare capacitor for special uses, have sometimes also a strip marked with a "+" in it, and only in this case the corresponding pin is positive.
 

Attachments

  • caps.jpg
    caps.jpg
    77.3 KB · Views: 781
Joined
Feb 5, 2008
Messages
6,252
Points
83
Hi Kyle, I got your email, and yes,

That is exactly how it is supposed to look like.
You catch on real quick ;)

Although, next time, use my Gmail account , not hotmail as I do not monitor the hotmail a lot as Gmail.

Nice pic HIMNL9 !

Well you see, it does not neccessarely have to be an electrolyctic capacitor, you can use any capacitor. Only electrolyctic and Tantalums are marked with positive and negative and have to be connected in specific way.
Other types, called 'Block' capacitors, can be connected any way you like.
I always use small SMD blocks for my drivers, you can harvest them out of... well, anything :)

You will see that with SMDs, the capacitors are denoted with brown casing.
But, there are lightbrown and darkbrown colors of those.
Light color is nF range,
dark coor is uF range (the one you need).

Not to be mistaken with black color, which are SMD coils (yeah, even those exist :D )

Good luck with your build!
 
Joined
Mar 30, 2010
Messages
67
Points
0
ok good :D

I'm good on capacitors :D

Still need a 3.3 ohm (I had a 330 ohm, not a 3.3)

Can I get the LM317 at my local electronics store or do I have to buy it online ?

How much voltage can I hook up to my driver ???

And how can I attach a picture to my message like HIMNL9 ???
 
Last edited:
Joined
Feb 5, 2008
Messages
6,252
Points
83
ok good :D

I'm good on capacitors :D

Still need a 3.3 ohm (I had a 330 ohm, not a 3.3)

CAN I GET THE LM317 CHIP AT MY LOCAL RADIO-SHACK, LA SOURCE OR WHATEVER OR DO I HAVE TO BUY IT ONLINE ??? (My most important question...duh!)

How much voltage can I hook up to my driver ???

And how can I attach a picture to my message like HIMNL9 ???
Yes, LM317 chip is fairly common in any electronics shop, you will find it anywhere.

Voltage is 2.5 V above the load. If the load is red laser diode, it needs
3V (red diode), + 2.5 V (Vdrop of the driver) = at least 5.5V to work.

I would reccomend any combination of batts resulting in more than 6V, since batteries voltage 'sags' , begins to drop with load.

You can attach a picture if you upload it to service like Photobucket, Imageshack, and them posting the code , called 'embed' code.

You can even upload your photos to forum's albums if you want.
 
Joined
Mar 30, 2010
Messages
67
Points
0
ok thanks again :D

So i'll just hook up 6V and my driver will drop it down to a good voltage that won't burn out my diode.

I'll send you and other picture :D
 
Joined
Feb 5, 2008
Messages
6,252
Points
83
ok thanks again :D

So i'll just hook up 6V and my driver will drop it down to a good voltage that won't burn out my diode.

I'll send you and other picture :D
Yes, the driver 'auto-senses' the voltage of the load and will supply exact voltage needed,
All you have to worry about is setting the current, and correct connecting :)

Everything else, replied on email.
 
Joined
Dec 29, 2009
Messages
3,136
Points
63
I have a question or two, if you do not mind. If my source voltage is 8.4 and I'm driving a red diode, this would be regulated until around Vf+2.5V. What does it do after that, just decrease the current as the battery runs out? My other question, when my source voltage is 8.4V and the voltage dropped by the 317 and diode is ~5V, what happens to the other 3.4V? Does it get turned into heat at the 317 chip, and if so, would a sink the size of a pen or flashlight torch host be sufficient?
 
Joined
Feb 5, 2008
Messages
6,252
Points
83
I have a question or two, if you do not mind. If my source voltage is 8.4 and I'm driving a red diode, this would be regulated until around Vf+2.5V. What does it do after that, just decrease the current as the battery runs out? My other question, when my source voltage is 8.4V and the voltage dropped by the 317 and diode is ~5V, what happens to the other 3.4V? Does it get turned into heat at the 317 chip, and if so, would a sink the size of a pen or flashlight torch host be sufficient?
1) Current starts to decrease slowly as the batteries run out, and eventually cuts out. You will notice when your laser can't burn as good as it did before.

2)The excess voltage supplied is turned into heat, yes. That is why no more that 9 V input is reccomended , as the IC heats a LOT.
At 300mA of current, if 9V is supplied, you have a total if 3 W of power consumtion of entire laser.
If the diode takes only 1 W, (3V at 300mA, aprox), you have 2W of heat to dissipate on a LM317 circuit. If you do not have any kind of heatsink mounted on it, it could be fatal.
 
Joined
Mar 30, 2010
Messages
67
Points
0
Hey Eudaimonium,

So I could hook up a 9V but no more, otherwise, this will be fatal as you said ?

And for 6V, would two flat 3V batteries work ???
 
Joined
Feb 5, 2008
Messages
6,252
Points
83
Hey Eudaimonium,

So I could hook up a 9V but no more, otherwise, this will be fatal as you said ?

And for 6V, would two flat 3V batteries work ???
'Fatal' would be overstatement, as though prolonged heat up on the driver, LM317 chip thermal protection kicks in and cuts off the power at 120°C .

But don't let that happen to you. You never know what could happen to the driver, perhaps some minor defects occur and make your expensive LD into expensive LED.
Not worth the risk.
 




Top