lasers power supply problem

[camilozk]

Hi!

I have 48 lasers connected in parallel as shown in the attached image. the lasers datasheet is in the the following link: http://media.laserfuchs.de/datasheets/LFD650-1-3(6x17).pdf

I am using a 3volts - 1amp power supply, and my problem is that the lasers connected to the grids B and C are sensibly weaker than the ones connected to A and D.

How can I properly correct this problem?

thanks!

 

[Martaine2005]

Hello,
Try putting jumper wires to the opposite corner. Sounds like you're getting a voltage drop.
48 lasers from a poor little 3v!!

Martin

 

[cjdelphi]

My money is on it drawing more current than it should and you're hitting 1amp+

Got a multimeter handy? Measure the current draw.... ?

 

[camilozk]

they should be using 720mA. 1A should be enough. I will measure it right away.

martin. jumper wires between what and what?

thanks!

 

[Martaine2005]

they should be using 720mA. 1A should be enough. I will measure it right away.

martin. jumper wires between what and what?

thanks!

720 mA is assuming maximum 15 mA.. 480mA @ 10mA... 1 Amp should be plenty.

Jumpers as in, another positive and negative to the side where voltage drops.

Martin

 

[camilozk]

ok. I connected another positive and negative from the same power supply and it improved just a little bit. they are still not performing at their best.

 

[Martaine2005]

Did you check the current as @cjdelphi suggested?
Also, what wire are you using? and length? It might be high resistance too.
But you are expecting a lot from such a small supply.

Martin

 

[camilozk]

I still couldnt check the current. The set up is part of an installation that is working at the moment.

the square has 2mts per side and I am using recycled telephone cable, but I tried the same set up in different locations and I actually had no problems...

when you say that I am expecting too much, this means that I should use a power supply with higher amperage?

thanks for the support!

 

[Martaine2005]

Not higher amperage, rather constant current. Lasers are current driven like Leds.
What have you done differently from when it worked and now? Power supply?

Martin

 

[camilozk]

same power supply. just different location.

I have an atx computer power supply and I was thinking to try this one out, but since it provides 3.3volts, and the datasheet from the lasers says that 3.3volts is the maximum, I am afraid to burn the lasers... I wouldnt like to burn them since it is 300€ material. what do you think?

 

[Martaine2005]

Personally, I don't think a diode would mind an extra 0.3v. But that's just my opinion.
I have never played with lasers so I can't even wire one up and tell you at what voltage it explodes!!

If you have the same setup, different location and different results, it must be something to do with the location.
You really need to check the current as cjdelphi suggested. Without that , we can talk all night and get nowhere..

Martin

 

[cjdelphi]

You can buy bags full of 1-5mw laser modules (resistor based) for a few bucks on ebay...

Lasers tend to be less forgiving than LEDS, they get bright and wham very dull quickly..

Telephone cable? How long? (Voltage drop issue?)

And when tested in another location it works? (Is that a different cable?)

 

[James Louis]

Increase your power supply, this may be the best solution. Everything is looking fine and you need to change the power supply as suggested by other members

 

[camilozk]

ey guys. thanks for your opinion.

I sorted it out. I was stupudly using a much longer cable than usual between the power supply and the system. I cut it and it got much better. anyway I am happy to experience these stupid issues since they help me learning.

I know about the bag of lasers from ebay, but since I am working in public installations I need to have certified lasers, which do not cost a bunch of bucks.

I measured the current and it was around 400ma...

thanks everybody to help me find the problem!

 

[cjdelphi]

Certified lasers?

Chinese made lasers, shipped out to a small company who then checks to make sure they work before reselling them at 10x the price?

So it was the cable length.. suspected that after you said it worked in a different location with the same supply...

Now it makes sense

 

[camilozk]

yup...

about lasers, yes, this is how it works, and unfortunately I am asked about the laser´s certification often and sometimes people come to measure the power of the lasers. I live in a country where they take this seriously, regardless how ridiculous sounds...

 

[Martaine2005]

My money is on it drawing more current than it should and you're hitting 1amp+

Hey cjdelphi......Shall I pm my paypal to you?

About those lasers...We also have strict laws on 1mw max lasers.
And the law takes it very seriously!
Some Ebay lazers, labelled as 1mw have been checked and found to be 10 to 100 times more powerful!.
Kids/teenagers have been arrested for pointing them at aircraft!..
Glad you eventually figured it out.

Martin

 

[cjdelphi]

They can't touch you ebay away .... they are not prohibited by customs unless they're marked 1+mw and these ones are not... I had a 5mw pointer taken off me by customs but in the same package just the laser / module no case no spring ... and because there was no markings on the 80mw laser they let it through keeping the 5mw!

 

[Martaine2005]

I couldn't possibly argue with that. I don't know about non-labelled lasers.
But I am sure the UK has a law for all pen-type, pointers etc to be 1mw.
Modules are different of course. Used for machinery, cutting etc..
I watched a series of Fake Britain, and lasers were one of the subjects.
I will see if I can find it and link it here.

Martin

 

[Martaine2005]

I found this..But the volume is low!

Martin