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ArcticMyst Security by Avery

M140 post-mortem: Was this driver a bad choice?

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Jun 16, 2014
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Just so I can picture it. Is this how you have yours wired? And what size capacitor did you use?

Laser Driver Setup.png

I'd eventually like to let picengrave control the laser by the dimmer somehow.

Thanks

Mike
 





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Apr 21, 2014
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@madmike8:

Yes, that schematic describes how I've wired the driver. The cap is 47uf/63V, just something I found in my scrap box, wired close to the driver module. I've got the whole thing mounted onto a large heat sink, probably overkill but it all fit together nicely:
attachment.php


Sorry for the poor focus, my phone camera is having a problem with close focus lately.

Picengrave looks pretty interesting from a quick glance, I'll take a closer look when I get a chance, thanks for the lead.

Cheers,
Joe
 

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I found this. Since I'll be using a arduino anyways I might be able to control laser intensity with this circuit.

arduino 0-10v output.png
 
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I found this. Since I'll be using a arduino anyways I might be able to control laser intensity with this circuit.

I'd be interested to hear how that works out if you try it :)

There's a PDF doc on the PicEngrave site that shows a cool option using a Maxim digital potentiomter. I might try that one out when I get the chance.
 
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We are using a Luxdrive to drive the laser. The 0-10v is to control the Driver's Dim circuit, not the laser.
 
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What a great site!
My experience was very similar to jameadows. Home brew LM350 driver on bench worked fine. I then bought a 2A driver with TTL modulation, also to drive from CNC. All set up on bench and working fine. I then had the great idea of keeping all the electronics adjacent to my PC and CNC driver circuitry and running 6 feet of wire to the LDR..... New M140 ordered.
I assume it was the length of cable that caused its demise?
John
 
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The electronics may not have been the problem . . .

Did you have the black heat sink on the laser diode when you were testing it ??

If not, it could have been overheating that caused the demise.

Even your current setup with metal clamps is not ideal . .

LarryDFW
 
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Hi Larry
I think you are confusing me with another member "jameadows"
My electronics were OK I think. Only change I made was adding 6 feet of twin cable to the LD which was heatsinked.
John
 
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6ft, wow. That would have several
microhenries of inductance at the bare
minimum. Couple that with the self
capacitance and it makes a pretty good
recipe for diode death. The driver should
always be as close to the diode as
possible. If they have to be separated by
more than a few inches, then some
oscilloscope testing is in order. That is
not to say that it could have been
something else. We can't rule out all
possibilities here, and there are many
possibilities. We don't know what driver
you are using.

This should have its own thread, BTW. Next
time start a new thread.
 
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I assume it was the length of cable that caused its demise?
John

That could have been a factor in my case, and also that I'd wired everything together with alligator clips, so there may have been some sporadic connections. After making a clean build it has been working reliably with the same driver. The driver is mounted on the heatsink near the LD. The power cord is about six feet long so I put a filter cap on the power inputs of the driver.

Cheers,
Joe
 
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Dec 20, 2014
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Hi Joe
I have ordered a new LD and the same driver as yours. I have the same requirements as yourself ie etching wood on my CNC.
thanks
John
 
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Hi
Does anyone have any experience of putting a moving coil ammeter in series with the laser diode. (using very short leads) Is this a bad idea?
John
 




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