Laser pointer discussion. Read/write reviews of laser pointers and laser pointer companies. Learn about all types of laser pointers and lasers

 Welcome to Laser Pointer Forums! If you are looking for a laser pointer or want to compare different laser pointer companies, you may want to check out the LPF Laser Pointer Company Database. The link will open in a new window for your convenience.

One laser store meets all your needs

 Laser Pointer Forums - Discuss Laser Pointers DIY driver problem

LPF List of Laser Pointer Companies (link opens new window)

09-12-2010, 03:54 AM #1
 Class 2 Laser Join Date: Dec 2008 Location: Spokane, WA Posts: 417 Rep Power: 16
Gata
Class 2 Laser

Join Date: Dec 2008
Location: Spokane, WA
Posts: 417
Rep Power: 16
DIY driver problem

Problem solved. I feel as dumb as I did after watching kipkay's video.

__________________
Cogito, ergo sum

Last edited by Gata; 09-12-2010 at 04:34 AM.

LPF List of Laser Pointer Companies (link opens new window)

09-12-2010, 04:06 AM #2
 Class 2 Laser Join Date: Feb 2010 Location: Australia Posts: 443 Rep Power: 11
hugo999999
Class 2 Laser

Join Date: Feb 2010
Location: Australia
Posts: 443
Rep Power: 11
Re: DIY driver problem

use the rule V= I * R
where r is ohms and I amperes, and voltage the constant of 1.25 for the LM317

so, 1.25/0.8= 1.56 ohms needed

there is also the other equation (R1*R2) / (R1+R2) = total resistance (this is for 2 resistors soldered in parallel).
__________________
<300mw red 660nm labby

<10mw green dx
<100mw 405nm phr803t
<200mw GGW-H20L
4 mirror RG spirograph
<5mw and <150mw 780nm
>900mw 445nm labby

Last edited by hugo999999; 09-12-2010 at 04:10 AM.

09-12-2010, 04:16 AM #3
 Class 2 Laser Join Date: Dec 2008 Location: Spokane, WA Posts: 417 Rep Power: 16
Gata
Class 2 Laser

Join Date: Dec 2008
Location: Spokane, WA
Posts: 417
Rep Power: 16
Re: DIY driver problem

So only 1.56 ohms is needed to get .8A?
__________________
Cogito, ergo sum

Last edited by Gata; 09-12-2010 at 04:20 AM.

09-12-2010, 05:00 AM #4
 Class 2 Laser Join Date: Feb 2010 Location: Australia Posts: 443 Rep Power: 11
hugo999999
Class 2 Laser

Join Date: Feb 2010
Location: Australia
Posts: 443
Rep Power: 11
Re: DIY driver problem

yes a 1.5 ohm resistor would work fine. note it will need to be about 3W
__________________
<300mw red 660nm labby

<10mw green dx
<100mw 405nm phr803t
<200mw GGW-H20L
4 mirror RG spirograph
<5mw and <150mw 780nm
>900mw 445nm labby

09-12-2010, 05:22 AM #5
 Class 2 Laser Join Date: Dec 2008 Location: Spokane, WA Posts: 417 Rep Power: 16
Gata
Class 2 Laser

Join Date: Dec 2008
Location: Spokane, WA
Posts: 417
Rep Power: 16
Re: DIY driver problem

The only ones I got on hand are 1/4W. What is the 3W needed for?
__________________
Cogito, ergo sum

09-12-2010, 06:29 AM #6
 Class 2 Laser Join Date: Feb 2010 Location: Australia Posts: 443 Rep Power: 11
hugo999999
Class 2 Laser

Join Date: Feb 2010
Location: Australia
Posts: 443
Rep Power: 11
Re: DIY driver problem

3W of electricity are going through it... if you try with a 1/4W its gonna end up in flames lol
__________________
<300mw red 660nm labby

<10mw green dx
<100mw 405nm phr803t
<200mw GGW-H20L
4 mirror RG spirograph
<5mw and <150mw 780nm
>900mw 445nm labby

09-12-2010, 06:42 AM #7
 Class 2 Laser Join Date: Dec 2008 Location: Spokane, WA Posts: 417 Rep Power: 16
Gata
Class 2 Laser

Join Date: Dec 2008
Location: Spokane, WA
Posts: 417
Rep Power: 16
Re: DIY driver problem

I ran the driver with a test load for about 3 minutes just to see how hot the LM317 got and the resistors seemed fine. But I will replace them when I get the chance to a higher wattage just to be safe.
__________________
Cogito, ergo sum

09-12-2010, 06:43 AM #8
 Class 3R Laser Join Date: Aug 2010 Posts: 1,249 Rep Power: 0
Toaster
Class 3R Laser

Join Date: Aug 2010
Posts: 1,249
Rep Power: 0
Re: DIY driver problem

So the watt rating on a resistance is only the upper limit of the resistor? The watt rating has always confused me.

09-12-2010, 07:00 AM #9
 Class 2 Laser Join Date: Dec 2008 Location: Spokane, WA Posts: 417 Rep Power: 16
Gata
Class 2 Laser

Join Date: Dec 2008
Location: Spokane, WA
Posts: 417
Rep Power: 16
Re: DIY driver problem

I have never professionally worked with electronics such as these, only in hobby projects and such, and I have never had a problem with different watt resistors. But with lasers things need to be precise and you have to do things a bit more carefully, so to be on the safe side I am not gonna plug in my 445 diode until I get some tougher resistors.
__________________
Cogito, ergo sum

09-12-2010, 07:16 AM #10
 Class 2 Laser Join Date: Feb 2010 Location: Australia Posts: 443 Rep Power: 11
hugo999999
Class 2 Laser

Join Date: Feb 2010
Location: Australia
Posts: 443
Rep Power: 11
Re: DIY driver problem

i once used a 1/4W resistor in a build using even less current then this. a few seconds later it got so hot it desoldered itself from the bread board lol
__________________
<300mw red 660nm labby

<10mw green dx
<100mw 405nm phr803t
<200mw GGW-H20L
4 mirror RG spirograph
<5mw and <150mw 780nm
>900mw 445nm labby

09-12-2010, 10:37 AM #11
 Class 2 Laser Join Date: Feb 2010 Location: Madrid, Spain Posts: 437 Rep Power: 16
Rafa
Class 2 Laser

Join Date: Feb 2010
Posts: 437
Rep Power: 16
Re: DIY driver problem

For .8A you will need 1.6Ohm with a rating of 1W or more.

Resistor rating is how much the resistor can dissipate itself, if too much power is passing thru it, it will ovearheat, and eventually burn, just like laser diodes.
__________________
Lasers:
~100mW 405nm from Erdabyz (L) akshakj <- Died once, working again. vid 1 vid 2(repaired)
~980mW 445nm in Ehgemus RPL style host, thanks to MR. DAGUIN vid
~25mW 532nm (potmoded) from DX (dead now, switch died and repair failed...)not moded vid
~50mW 532nm "star cap" style found in the bus. Yeah, lol.
~6mW 635nm diode laser pic 1 pic 2
~250mW 650nm extracted from 20x DVD burner. <- dead vid 1 vid 2
~130mW 650nm extracted from 16X DVD burner. <\$15 to make! LPF thread

~100mW 780mn extracted from 52x CD burner. <- dead cremation vid

09-12-2010, 11:28 AM #12
 Class 2 Laser Join Date: Feb 2010 Location: Australia Posts: 443 Rep Power: 11
hugo999999
Class 2 Laser

Join Date: Feb 2010
Location: Australia
Posts: 443
Rep Power: 11
Re: DIY driver problem

Quote:
 Originally Posted by Rafa For .8A you will need 1.6Ohm with a rating of 1W or more. Resistor rating is how much the resistor can dissipate itself, if too much power is passing thru it, it will ovearheat, and eventually burn, just like laser diodes.
1W is still not enough.
about 3W of electricity will be going through the resistor (4Vx0.8A=3.2W).
to be safe i would go with a 3W resistor, using anything less is asking for trouble (even a 1W, it would work for a while but eventually burn out).
__________________
<300mw red 660nm labby

<10mw green dx
<100mw 405nm phr803t
<200mw GGW-H20L
4 mirror RG spirograph
<5mw and <150mw 780nm
>900mw 445nm labby

09-12-2010, 12:39 PM #13
 Class 2 Laser Join Date: Apr 2009 Location: London Posts: 482 Rep Power: 24
jaycey
Class 2 Laser

Join Date: Apr 2009
Location: London
Posts: 482
Rep Power: 24
Re: DIY driver problem

Just upgraded the resistor on my 445nm driver to a 1 watt 0.5 ohm resistor.

Anyone tell me the max output, because thats what it is running at now

Just tested it on the Mrs (she didnt know LOL) and at 15metres she thought a wasp had stung her...after about 3 seconds Double LOL!

09-12-2010, 01:11 PM #14
 Class 2M Laser Join Date: Jun 2010 Location: DFW, TX Posts: 718 Rep Power: 38
jib77
Class 2M Laser

Join Date: Jun 2010
Location: DFW, TX
Posts: 718
Rep Power: 38
Re: DIY driver problem

I thought it was [Voltage drop across the resistor X Current = W] in the case of LM317 the regulator will always maintain a 1.25 voltage drop across the resistor so that is 1.25 x .8 = 1 Watt.
__________________

50mW O-Like New Pocket Greenie OLCGL50

100mW+ PHR/MicroBoost V1/Jayrob Chrome Pocket Mini (140mA)
445nm, Flexdrive V5, Ehgemus 18650 Polished Host (Murdered )
445nm, JibDrive 1.2A, Ehgemus 1x26650 Alien Host
LCC Red 200mW in Custom Ehgemus CR123A Host

FS - My cheap LM1117 driver: >>LINK<<

レイセーたちはすごいですよ。

Last edited by jib77; 09-12-2010 at 08:50 PM.

09-12-2010, 04:09 PM #15
 Class 2 Laser Join Date: Feb 2010 Location: Madrid, Spain Posts: 437 Rep Power: 16
Rafa
Class 2 Laser

Join Date: Feb 2010
Posts: 437
Rep Power: 16
Re: DIY driver problem

Quote:
 Originally Posted by jib77 I thought it was [Voltage drop across the resistor X Current = W] in the case of LM317 the regulator will always maintain a 1.25 voltage drop across the resistor so that is 1.25 x .08 = 1 Watt.
Thats right.
__________________
Lasers:
~100mW 405nm from Erdabyz (L) akshakj <- Died once, working again. vid 1 vid 2(repaired)
~980mW 445nm in Ehgemus RPL style host, thanks to MR. DAGUIN vid
~25mW 532nm (potmoded) from DX (dead now, switch died and repair failed...)not moded vid
~50mW 532nm "star cap" style found in the bus. Yeah, lol.
~6mW 635nm diode laser pic 1 pic 2
~250mW 650nm extracted from 20x DVD burner. <- dead vid 1 vid 2
~130mW 650nm extracted from 16X DVD burner. <\$15 to make! LPF thread

~100mW 780mn extracted from 52x CD burner. <- dead cremation vid

09-12-2010, 04:47 PM #16
 Class 2 Laser Join Date: Dec 2008 Location: Spokane, WA Posts: 417 Rep Power: 16
Gata
Class 2 Laser

Join Date: Dec 2008
Location: Spokane, WA
Posts: 417
Rep Power: 16
Re: DIY driver problem

Quote:
 Originally Posted by jaycey Just upgraded the resistor on my 445nm driver to a 1 watt 0.5 ohm resistor. Anyone tell me the max output, because thats what it is running at now Just tested it on the Mrs (she didnt know LOL) and at 15metres she thought a wasp had stung her...after about 3 seconds Double LOL!
What regulator are you using? LM317? If so then your max out put would be around 1.5A, the max that the LM317 can put out.

When I lived at home I did that to my brother all the time on the back of the neck, he always though something was stinging him.
__________________
Cogito, ergo sum

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

All times are GMT. The time now is 10:40 PM.

 -- DarkShadows V5 -- Responsive LPF -2562016 -- Default Style Contact Us - Laser Pointer Forums - Archive - Top