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Questions about operating principle of show lasers

lostbeam488

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Oct 15, 2020
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I'm currently trying to build myself, eventually, an rgb show laser. Currently I've completed an rgb laser module, which at this point I've been using a triple output power supply to control each of the laser diodes, I'm still looking for analog drivers that can do 1.5A. After I get the drivers, my next step will be to buy an xy galvo set, probably the ~$80 ebay ones, but now I'm starting to have more questions and confusion about how the galvos and laser drivers are controlled collectively. So far I understand that in order to control the lasers you need to be able to control 3 analog outputs that go to the 3 analog laser drivers, with high speed and accuracy. I also know that the galvos need an analog signal. Some of the threads I've seen mention a DAC or a sound card to control the galvo driver, are the galvos actually controlled by a soundcard with audio like analog signals? And are the laser driver signals also controlled using a soundcard or DAC? If not, what sends the laser driver signals, how are both the galvos and laser drivers controlled at the same time, what kind of hardware and software do I need to achieve all of this? If anyone knows a thread or website that goes into detail into building all of this, that would be super helpful.
 





kecked

0
Joined
Jun 18, 2012
Messages
949
Points
63
You might do better on Photonlexicon.com

you need show software that drive a dac. The output of the dac gives you the color modulation data and position data for the galvos. I would not skimp on the galvos unless all you plan to do is beams. You want galvos that at a minimum can provide 30kps @8degrees of deflection. I favor the pangolin galvos and software but there is plenty out there. The other software package I have seen do magic is called LSX.

The analog drives for the diodes are available from a lot of sources. X-woisee on eBay was my go to but OptLasers sells nice ones too. I favor ones that have a blanking and bias control plus current control. This lets you set the diode just below the current when it turns on and gives better black. The blanking then jumps directly to the turn on voltage rather than projecting a dim dot that shows upon blanked lines.

hooe that helps some. Honestly you can buy a finished projector so cheap build isn’t worth it and unless you only want to play at home, you need a lot of safety stuff installed and a certification to use it.
 

additude

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Mar 3, 2023
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59
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I only know some conceptual thinking, so if I suggest something dubious, just throw something at me....I'll go away. But I would ask two things of myself, how professional of a unit would I want to make and second, is this something an Arduino or a Hardkernel ODROID could be adapted to be used to control? Just a thought...
 

lostbeam488

New member
Joined
Oct 15, 2020
Messages
9
Points
1
You might do better on Photonlexicon.com

you need show software that drive a dac. The output of the dac gives you the color modulation data and position data for the galvos. I would not skimp on the galvos unless all you plan to do is beams. You want galvos that at a minimum can provide 30kps @8degrees of deflection. I favor the pangolin galvos and software but there is plenty out there. The other software package I have seen do magic is called LSX.

The analog drives for the diodes are available from a lot of sources. X-woisee on eBay was my go to but OptLasers sells nice ones too. I favor ones that have a blanking and bias control plus current control. This lets you set the diode just below the current when it turns on and gives better black. The blanking then jumps directly to the turn on voltage rather than projecting a dim dot that shows upon blanked lines.

hooe that helps some. Honestly you can buy a finished projector so cheap build isn’t worth it and unless you only want to play at home, you need a lot of safety stuff installed and a certification to use it.
This was very helpful, thanks! You cleared up the confusion for me about the signals. How does the dac output both of the signals at the same time? Is there one singular output that has both the galvo and color controls, or does it output two signals? And I’ve looked at the optlaser drivers, they look good but they are expensive, so I’m trying to reverse engineer them, as I know the components for a single board have to be no more than a couple bucks.
 

kecked

0
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Jun 18, 2012
Messages
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63
The dac spits out color and position at the same time from software. lookup ilda connector pinout
 

OldNo7

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Nov 13, 2012
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79
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8
If you go the sound card route you need one that does 5.1 surround sound. Each speaker output is hooked up to either the analog in of a laser driver or an analog input on the galvo driver.
 

kecked

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Buy a dac and proper software or you’ll be making nothing more than squiggle lines for life.
 

lostbeam488

New member
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Oct 15, 2020
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If you go the sound card route you need one that does 5.1 surround sound. Each speaker output is hooked up to either the analog in of a laser driver or an analog input on the galvo driver.
If I go this route, how do I make sure the galvo signals are +5/-5v output and max, and for the rgb outputs how would I make it so that the outputs are 0 to 5v max? Is there a software that can output all of this through the sound card?
 

kecked

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Any show laser dac combination should do this for you. There is a standard called the ilda connector
 





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