Testing laser output

**laserLips** · 06-26-2014, 12:57

Hi
When testing laser output for a single laser module, what would you say is a fair test pattern to run while testing the power?

Do you simply have a frame with a dot in it?
Do you have a huge squiggle?
Do you have a dot that you've pressed many times to creat more power?

Which frame do you use to test a module fairly?

Graham

**jbinks** · 06-27-2014, 03:16

Hey Graham

I'm by no means an expert but I'm pretty sure you need to be mindful of the way in which your software actually creates it's output. For example, just having a frame with a single point may not actually produce a constant beam due to the way the software "scans" the overall scene.

I understand that the only way to get a true constant beam in QS is to use the QuickBeams and only to use a single beam with all other output disabled.

Personally, if I wanted to get a proper measurement I would probably be more inclined to "hotwire" the module driver with a constant 5v (?) supply and defeat the projector's interlock system (obviously.... be careful doing this!!). Note that this method would not require any ILDA connection. Just remove the existing modulated input from the driver and substitute a constant +5v respective to the projector's ground, stick in one of those "interlock bypass" dongles you get with new projectors, turn the key and off you go.

Like I said, I'm no expert, but I'm trying to learn as much as possible so if I'm wrong on any points then I'm more than happy for someone to shoot me down and give a better answer!

Cheers,
John

**norty303** · 06-27-2014, 03:51

If you are testing using a DAC, then be aware you will not get full power on a lot of them (the FB3 certainly has a little 'off time' each cycle for 'housekeeping')
I use the Lasermedia test pattern (the 45 degree rotated square within a square) as this is fairly well regarded as having the most 'on' time. I then shrink the size to zero, or just measure before the scanners.

In testing, I found that using the Lasermedia gets me at least 95% of the power that a constant 5V signal does. So I can do the adjustments in my head. It is much easier for me to use the Lasermedia test than it is to rig up the 5V supply, so i tend to use this most. When you're dealing with multiple watts of power, 50mW here or there isn't really too relevant.

**buffo** · 07-01-2014, 06:43

If you have Pangolin's LD2000, according to Bill Benner the *best* way to get a solid, full-power beam is to load up the abstract generator, make a white circle, and then shrink the size down to zero. Something about the way the abstract generator works ends up reducing (if not eliminating) the blanking interrupts between frames, so you end up with as close to continuous output as you'll ever get on a controller.

Adam