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# """""My DIY Red Shoebox Laser"""" question

#### creanzworldd

##### New member
"""""My DIY Red Shoebox Laser"""" question

Going by his circuit board,i believe it is flogger?, how long can the sony16x DVD diode be let on before it will die? [smiley=2vrolijk_08.gif] [smiley=2vrolijk_08.gif] [smiley=2vrolijk_08.gif] [smiley=2vrolijk_08.gif] [smiley=2vrolijk_08.gif] [smiley=2vrolijk_08.gif] [smiley=2vrolijk_08.gif] [smiley=2vrolijk_08.gif] [smiley=2vrolijk_08.gif] [smiley=2vrolijk_08.gif] [smiley=2vrolijk_08.gif] [smiley=2vrolijk_08.gif] [smiley=2vrolijk_08.gif] [smiley=2vrolijk_08.gif]

#### chido

##### New member
Re: """""My DIY Red Shoebox Laser"""" question

His username is flogged. He's using ddl's circuit, and what you're asking is almost imposible to predict. It depends if you're going to use a heatsink, how much current you're planning on powering the diode with, how long you'll keep it on (duty cycle), etc.

#### wooooooolazer

##### New member
Re: """""My DIY Red Shoebox Laser"""" question

it depends, how much current are you going to put into it, and guessing doesnt count you have to measure it with a multimeter by putting it in series wit a sensing resistor (1ohm) then setting it to voltage which will give you the current.

If you set it to 250ma or less the lifetime will be quite a long time, if you go to about 350ma the lifetime would shorten some even if it was heatsinked. Above that the lifespan reduces drasticly and the output power doenst even go up very much.

...lazer... ;D ;D ;D

#### flogged

##### New member
Re: """""My DIY Red Shoebox Laser"""" question

wooooooolazer said:
it depends, how much current are you going to put into it, and guessing doesnt count you have to measure it with a multimeter by putting it in series wit a sensing resistor (1ohm) then setting it to voltage which will give you the current.
That's one way to do it. When I'd finally finished my shoebox laser, before turning it on for the first time, I broke the negative line coming from the battery pack and attached it to my multimeter. My old analog multimeter will only measure up to a quarter amp of current (250 mA), so I set it to that. I then turned the pot ALMOST all the way down. When I flipped the switch the circuit came to life with about 40 mA of current. The diode was still looking like an LED at this point. I then slowly (with trembling fingers) turned the pot up, watching the LD get much brighter, while at the same time watching the amount of current slowly increase on the meter. I stopped around 2205mA. Turned off the pointer, unattached the multimeter, soldered up the wires and it was done. I also marked the pot to note that level.

As to the OPs question.. as noted it's impossible to predict. I'm assuming you're using AixiZ housing. First make certain the back the diode casing is in contact with the case (I'm not familiar with the AZ housing). If you want to be conservative run the laser until the housing feels no more than body temperature warm (40C.. 100F). This can take anywhere from 15-30 seconds to several minutes or more, depending on your setup. Allow at least a couple minutes to cool off before using again.

#### wooooooolazer

##### New member
Re: """""My DIY Red Shoebox Laser"""" question

dont use the multimeter in paralel while measuring current, it will 99% of the time kill he diode, and i think it wouldnt be right seeing as you got a reading of 2205ma, the resistor is by far the easiest way without any risk to your diode to measure the current.

...lazer... ;D ;D ;D

#### Gazoo

##### Active member
Re: """""My DIY Red Shoebox Laser"""" question

wooooooolazer said:
dont use the multimeter in paralel while measuring current, it will 99% of the time kill he diode, and i think it wouldnt be right seeing as you got a reading of 2205ma, the resistor is by far the easiest way without any risk to your diode to measure the current.

...lazer... ;D ;D ;D
Another safe way to measure is between the battery and the circuit. But I still like the 1 ohm resister way of measuring current because it is more accurate and much more convenient.. And I know he meant 225ma's.

#### wooooooolazer

##### New member
Re: """""My DIY Red Shoebox Laser"""" question

oh, in that case nevermind, i thought you were putting it in paralel on the leads of the diode.... :-[

...lazer... ;D ;D ;D

#### creanzworldd

##### New member
Re: """""My DIY Red Shoebox Laser"""" question

alright...what would you guys suggest i set the Ma at, so i have a powerul laser,but not too powerfull so that i will kill it?

#### wooooooolazer

##### New member
Re: """""My DIY Red Shoebox Laser"""" question

about 250ma is good, its a mixture of good burning power but a long life, any past that it will be a better burner but it wont last as long so i would keep with 250ma for now.

...lazer... ;D ;D ;D

#### Hemlock_Mike

##### Well-known member
Re: """""My DIY Red Shoebox Laser"""" question

CW --

Wlaser is telling you right. 250 mA (with good heatsinking) will give you ~175 mW of red. This number comes up all the time here.
If you turn it up to 300 mA, you can get ~200 mW out but power and diode life vary from diode to diode.
At 300 mA, you have reached the knee of the curve, the point of diminishing returns and it's a slippery slope down from there.

Mike

#### creanzworldd

##### New member
Re: """""My DIY Red Shoebox Laser"""" question

alright.tell me if this is good enough for 250ma-a 16x sony dvd burner diode,and the heat sink is from a dealextreme red 5mw module. is the heatsink suitable?

#### Gazoo

##### Active member
Re: """""My DIY Red Shoebox Laser"""" question

I just want to add running SenKat's diode with 160ma's is good for burning. It all depends on what you want to do. If you want to run with 250ma's, the aixiz type module will provide adequate heatsinking as long as you keep your duty cycles short. More important than anything IMO is to use good current regulation, and the LM317 is a good choice provided you understand you need to use 6 nimh or alkaline batteries to power it. Nimh are preferred because they hold up much better.

#### desslok

##### New member
Re: """""My DIY Red Shoebox Laser"""" question

FYI, I wanted mine to engrave black plastic pretty, which means it must start burning pretty much instantly. The threshold where my Senkat diode did this to a spoon from Starbuck's was 267 mA. I know they are all different but this seemed to be the lowest mA where it would burn black plastic immediatley and smoke.

#### creanzworldd

##### New member
Re: """""My DIY Red Shoebox Laser"""" question

alright ill once i buy the doide, ill set it at 250,and c if thats suitable....but im worried if the heatsink i got from dealextreme will stand that ma.

#### chido

##### New member
Re: """""My DIY Red Shoebox Laser"""" question

What heatsink, can you post a link?  :-?

#### creanzworldd

##### New member
Re: """""My DIY Red Shoebox Laser"""" question

no sry not yet...dealextreme(dot)com...then once u r thr,go to the "red lasers"section, then look 4 the "focusable red dot" 5mw module> i think it is like \$4.30?well just go there,find it,and tell me if the little heatsink is ok.