RGB Lasers LP2000 & DAC/Software.

[simondavidbond]

Hi everyone,
I'm new here, so sorry if I've put this in the wrong forum!

I have just bought an ex -demo LP2000, but I don't have any way of controlling it via the ILDA port. In time I will be using my Arduino Due & some external op amps for basic beam effects.

But until then please can anyone advise me the options regarding 'Soundcard DACs'. I found much info from about 8 or 9 years ago, so I'm unsure if you can still get those CMedia external USB soundcards?

Also, are there any circuit diagrams available for the 'Correction Amp'? Not sure but is this a set of analogue/linear components which take the X, Y & Modulation outputs from the soundcard & convert into the differential signals needed?

I guess I'm asking if there is any advice on how I could build a correction Amp from its circuit, & exactly where to connect wires on a specific soundcard??

A bit of a big ask, but I'm hoping you will be able to help me.

Thank you,

Si Bond.

 

[Grix]

Sound card DACs are generally not a good option anymore, you can get normal DACs for pretty much as cheap and with much less hassle. For example Helios: http://pages.bitlasers.com/helios/

EDIT: I saw your post on photonlexicon too so it seems you already know about it.
You mention the arduino due, I actually used that as a prototype board when I developed the helios, so you should be able to modify the helios firmware to run on it if you want to try: https://github.com/Grix/helios_dac/tree/master/firmware
The github repo also contains circuits for an external DAC and correction amps that can be used with the arduino due.

ILDA spec is here: www.laserist.org/StandardsDocs/ILDA_ISP99_rev002.pdf
color channels are similar to XY, but unipolar instead of bipolar, basically one line goes from 5V to 0V instead of 5V to -5V like for the position signals.

 

[simondavidbond]

Thank you so much,
I'm saving up for your Helios DAC, but it will take me a while, as I'm unable to work at mo as I'm recovering from a spinal problem. But lasers are keeping me sane. I need to check that that the laser works thru the ILDA port. I was thinking of a quick test using 3 potentiometers across a +5v & 0v supply for the R, G & B level inputs & the X & Y pots of a joystick across a +10v & - 10v supply to manually steer a static beam. Just briefly & safely to check if all is well. But unsure how the differential inputs of the laser will react!?

Thanks for your help with your External DACs & correction amps.resources. I wasn't able to see them in the files you mentioned. I will have a proper look next time I can use a laptop.
But thank you, & I will let you know how I get on.
Best regards,
Simon B.

 

[diachi]

Looks like Grix has you sorted out! Have fun!

 

[Grix]

I need to check that that the laser works thru the ILDA port. I was thinking of a quick test using 3 potentiometers across a +5v & 0v supply for the R, G & B level inputs & the X & Y pots of a joystick across a +10v & - 10v supply to manually steer a static beam. Just briefly & safely to check if all is well. But unsure how the differential inputs of the laser will react!?

For the colors it should work, you can just keep the - line at 0V and vary the + line from 0 to 5V.

For XY it should also work in theory, as the inputs are differential it doesn't really matter what the absolute voltages are, only the voltage differences. But just in case the projector is not designed to handle absolute voltages of 10V you can try to vary from -5V to 5V instead. This will only give you half the scanning width, but it will let you know if the projector works fine like you said.

 

[simondavidbond]

Thanks for your advice. I shall limit the test voltages to +-5v. I think I might use +-3v first & measure the Galvo deflection angles, as the RGB Lasers LP2000 user manual indicates the ILDA Galvo signals are 3v. Unless it's a typo, I shall enquire with RGB themselves.

I wonder how I would use your Helios DAC if indeed the voltages are that low? Unless there is an adjustment somewhere? Thing is the manufacturer calls it an 'ILDA Port' or interface. You'd think they'd conform to the ILDA Standard. Otherwise different DACs could potentially overdrive certain projectors!
I don't really want to have to make voltage translators with even more op amps!

Thanks for your help.

Simon B.

 

[Grix]

I highly doubt they use different voltages for the ilda port than the spec allows, that would be pretty ridiculous. Maybe it converts the voltage at the port to a different one for the galvos inside the projector

 

[10fenny]

Isn't the point of ilda is to be standerdized?

 

[simondavidbond]

Hi,

Just had this from RGB:

"Hello Simon,

Modulation is analog 0 – 5V the scanners are ( I believe they are CT6210 ) +/- 2.5V"

I'm so glad I didn't just connect Standard ILDA 10v levels!! I can build a resistive attenuator, or maybe use op amps.

How strange! One assumes connecting ILDA levels to an ILDA port would be straightforward.

I will let you all know how I get on.

Thanks,
Simon B.

 

[Grix]

Hi,

Just had this from RGB:

"Hello Simon,

Modulation is analog 0 – 5V the scanners are ( I believe they are CT6210 ) +/- 2.5V"

I'm so glad I didn't just connect Standard ILDA 10v levels!! I can build a resistive attenuator, or maybe use op amps.

How strange! One assumes connecting ILDA levels to an ILDA port would be straightforward.

I will let you all know how I get on.

Thanks,
Simon B.

Are you sure they are talking about the levels at the ILDA port and not the scanners internally?