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DIY RED LASER (first ever for me)

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dylantrevors

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it all started when i watched styropyro's video on youtube.

thanks alot man! this is probably the first electrical project ive done besides putting a killswitch on my guitar. anyways i bought a project case at radioshack and have my battery pack and switch wired up. im still waiting on my aixiz module since its coming form china. i got my diode from what i believe to be a dvd burner on a broken laptop. ive tested the diode and it does work. its pretty bright i might add.

i was just wondering if i do NEED a 100ohm pot for this project. i have a 10k pot but i dont know if that will work.

im just getting into lasers so please help me out.
thanks alot!
 





Zom-B

Zom-B

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You cannot use the 10k pot as it's resistance is 100 times too large.

What you can do is using fixed resistances of 5 ohm and up (less ohm is brighter laser). Also don't forget to short the cap before connecting the laser to it! (fixing the cap to the laser is the safest bet)
 
styropyro

styropyro

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I'm glad you liked the video, but please don't use that tutorial ;D That "driver" I made really isn't good enough to safely power a laser diode. I made that video before I really knew what a proper driver was. For a driver, either build a DDL circuit or buy one from here.

Also, how did you test the laser diode? DON'T just hook it up to 2 AA batteries because that could easily kill it! Was the laser diode from a 16x DVD burner?
 
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dylantrevors

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wel i did actually just hook it up to 2 batteries. :-/ also do you think you could give me a diagram of the circuit so i know what exactly to build?

thanks
i dont think it was from a 16x. i had a laptop in my dads office that i ripped apart and stole the diode out. im pretty sure its at least 75mW.
its extremely bright. :) it lights up the whole office in the dark.
i emailed my local pc repair shop and asked if they had any broken dvd burners that i could have so im waiting on that.
and i dont know what you mean by short the cap.

elaborate?
 
styropyro

styropyro

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dylantrevors said:
wel i did actually just hook it up to 2 batteries. :-/ also do you think you could give me a diagram of the circuit so i know what exactly to build?

thanks
i dont think it was from a 16x. i had a laptop in my dads office that i ripped apart and stole the diode out. im pretty sure its at least 75mW.
its extremely bright. :) it lights up the whole office in the dark.
i emailed my local pc repair shop and asked if they had any broken dvd burners that i could have so im waiting on that.
and i dont know what you mean by short the cap.

elaborate?
Click to expand...
A diagram of a good circuit for driving your diode can be found here. A more simple diagram can be found here. Hooking the laser up to the batteries like that shortens the lifetime of those diodes significantly, most don't last over an hour. Also, it is important to know what type of DVD burner the diode came from (12x, 16x, 20x etc.) because then we will know what current to drive it at.
 
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dylantrevors

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ok i just looked up that specs on the laptop and it writes dvds at 8x. seems pretty weak but its my first laser so im not really complaining. do you think 8x will burn?
 
styropyro

styropyro

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dylantrevors said:
ok i just looked up that specs on the laptop and it writes dvds at 8x. seems pretty weak but its my first laser so im not really complaining. do you think 8x will burn?
Click to expand...
It will burn, but you won't be able to push it that hard. I've never messed with an 8x diode before, but I think something around 90mA-100mA should be a good current. If you want to upgrade you can always get a 16x DVD burner diode for $20 that you can safely push to 200mW from here.
 
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dylantrevors

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ok. i will probably buy a 16x diode later since i have to projects going right now. when you say i should use 90-100mA could you elaborte on how i would go about wiring my circuit?
 
styropyro

styropyro

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dylantrevors said:
ok. i will probably buy a 16x diode later since i have to projects going right now. when you say i should use 90-100mA could you elaborte on how i would go about wiring my circuit?
Click to expand...
For that you can replace the two 10 ohm resistors with two 25 ohm resistors, and if you want you can leave off the pot. Here's a diagram on how to wire your circuit (I changed the values on the circuit and took off the pot on the diagram) Thanks Rog8811 for the pic to edit!
 

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styropyro

styropyro

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dylantrevors said:
great thanks. also i have a bunch of 16v 100uf capacitors are those alright?
Click to expand...
Those will work fine. Make sure you short your capacitor before soldering on the laser diode though! To short the cap just solder a wire across the leads of the capacitor, and after you have soldered on the laser diode, you can take off the wire on the capacitor.
 
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dylantrevors

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alright.
thanks man you really helped me out on this one.

i appreciate everything especially introducing me to lasers :'(
tears of joy! hahaha
 
styropyro

styropyro

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dylantrevors said:
alright.
thanks man you really helped me out on this one.

i appreciate everything especially introducing me to lasers :'(
tears of joy! hahaha
Click to expand...
I'm glad I could help :) Us people at LPF like to help out people ;D Feel free to ask any other questions if you have any while building the circuit.
 
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dylantrevors

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hey i have a question. i ripped open an old cd drive today to see if i could even find a diode. what i found was a strange square shaped chip attached to a ribbon cable. it looked like it had a crystal in it.

is this some other type of diode?
 
styropyro

styropyro

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dylantrevors said:
hey i have a question. i ripped open an old cd drive today to see if i could even find a diode. what i found was a strange square shaped chip attached to a ribbon cable. it looked like it had a crystal in it.

is this some other type of diode?
Click to expand...
In that CD drive there is an invisible 1mW Laser Diode which is basically useless. There should be a diode in there that looks exactly like the one you pulled from the DVD burner.
 
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