DIY Homemade laser diode driver

[troop231]

Hey, Is it necessary to use 1% Tolerance Metal-Film resistors instead of 5% Tolerance Carbon-Film resistors? (standard type). Would the 1% ones be better? Or does it not make a difference? Thanks!

 

[amkdeath]

Hey, Is it necessary to use 1% Tolerance Metal-Film resistors instead of 5% Tolerance Carbon-Film resistors? (standard type). Would the 1% ones be better? Or does it not make a difference? Thanks!

Abray, troops avatar is the pin out.

thanks troop,

amk

 

[jtbarclay]

Just a note for anyone building this circuit, If you're using a pot in your design and a "safety" resistor. Make your safety resistor a little smaller than the suggested.

Example: For my red laser the suggested resistor is 5 ohms, but because the pots never quite reach 0 ohms you will never reach full power. I'm going to go back to my design and use 3 10ohm resistors to come up with 3.33 ohms and then carefully with a meter adjust the pot until I reach 250ma.

 

[amkdeath]

Just a note for anyone building this circuit,  If you're using a pot in your design and a "safety" resistor.  Make your safety resistor a little smaller than the suggested.

Example:  For my red laser the suggested resistor is 5 ohms, but because the pots never quite reach 0 ohms you will never reach full power.  I'm going to go back to my design and use 3 10ohm resistors to come up with 3.33 ohms and then carefully with a meter adjust the pot until I reach 250ma.

the micro sized (bout the size of my pnky nail) 100 ohm pots I sue go to 0.5ohms at minimum. so, 5.5 ohms isnt too bad, I lose liek 10mA or so, but thats not necessarily bad, the less mA, the more life.

but his suggestion is good. go for like 3 ohms, then using a multimeter CAREFULLY mark out 250mA, any more and ull kill the diode.

 

[troop231]

[quote author=troop231 link=1185701612/735#736 date=1199759923]Hey, Is it necessary to use 1% Tolerance Metal-Film resistors instead of 5% Tolerance Carbon-Film resistors? (standard type). Would the 1% ones be better? Or does it not make a difference? Thanks!

Abray, troops avatar is the pin out.

thanks troop,

amk[/quote]

Um, your welcome? lol now how about someone please answering my question about the resistor tolerances. Thanks! ;D

 

[amkdeath]

[quote author=amkdeath link=1185701612/735#737 date=1199760221][quote author=troop231 link=1185701612/735#736 date=1199759923]Hey, Is it necessary to use 1% Tolerance Metal-Film resistors instead of 5% Tolerance Carbon-Film resistors? (standard type). Would the 1% ones be better? Or does it not make a difference? Thanks!

Abray, troops avatar is the pin out.

thanks troop,

amk[/quote]

Um, your welcome? lol now how about someone please  answering my question about the resistor tolerances. Thanks!  ;D[/quote]

its not gonna make too much of a difference, it jsut might me 5% + or - so plus or minus .5 ohms, which shudent be a problem.

thanks,

amk

 

[Abray]

about your question, it just matters about how secure you want your circuit to be. I think the tolerance is how much the resistor actually varies from its set resistance. so a 100 ohm resistor might actually be resisting only 95 or up to 105 at some times. the 1% would be at 99 or 101.

oh and I figured out the pinout, and got my blu-ray working!

its AMAZING!! i'll probably get pictures as soon as I can!

 

[troop231]

about your question, it just matters about how secure you want your circuit to be. I think the tolerance is how much the resistor actually varies from its set resistance. so a 100 ohm resistor might actually be resisting only 95 or up to 105 at some times. the 1% would be at 99 or 101.

somebody correct me if I am wrong

You are correct, but does the tolerance really matter at all in this circuit? I dont want to fry a diode because of the tolerance. Thanks!

 

[Gazoo]

[quote author=Abray link=1185701612/735#742 date=1199764651]about your question, it just matters about how secure you want your circuit to be. I think the tolerance is how much the resistor actually varies from its set resistance. so a 100 ohm resistor might actually be resisting only 95 or up to 105 at some times. the 1% would be at 99 or 101.

somebody correct me if I am wrong

You are correct, but does the tolerance really matter at all in this circuit? I dont want to fry a diode because of the tolerance. Thanks! [/quote]

No it doesn't matter. You can take a multimeter and measure the resistance of the resistor, and I believe you will find it to be what it is rated at. Now a 1 meg resistor might be a different story..

 

[troop231]

Ok, one more thing, what wattage rating of resistors do I need to buy? 1/4 Watts or 1/2 Watts? I know that two 1/4 watts in parallel gives u 1/2 total watts. But is size a big difference also? Thanks!

 

[Gazoo]

The total rating should be 1/2 watts. To figure it out do this:

P = 1.25 X 0.250ma's = 0.3125 watts

The 1.25 is the reference voltage of the LM317..

 

[amkdeath]

can anyone answer my question on what you gotta do to the bluefusion drivers to make em work on bluray?

thanks,

amk

 

[Gazoo]

can anyone answer my question on what you gotta do to the bluefusion drivers to make em work on bluray?

thanks,

amk

I thought that question was answered in the first thread where his GB is.

 

[busterhax]

whered you get that tiny 47uF cap you used in the pic of the breadboard?

 

[troop231]

whered you get that tiny 47uF cap you used in the pic of the breadboard?

You can use a 10uf 16V Cap just the same, in fact others recommend this. But if you truly want the 47uf, then you can buy one at RadioShack (35V, not 16).

 

[amkdeath]

whered you get that tiny 47uF cap you used in the pic of the breadboard?

try digikey, or mouser