ILDA standard question

[bubble and tweak]

HI,

I'm new here so hello to you all!

I have made some simple lissajous patterns using a 35mw green laser, and 2/3 computer fans with mirrors attached to the front at a slight angle, with pots controlling the speed, but now I wanna get a bit more advanced!

So I've found out about xy Galvo's, points per second and ILDA test aptterns, but what i'm having trouble understanding is how you send the signals to the galvo drivers, is the ILDA test pattern a patch that you upload to a micro controller that outputs the vector points?

I'm getting a little lost so any help or shove in the right direction would be really useful.

Cheers,

Rich

[andythemechanic]

Hi Rich,

and welcome at PL! As you maybe know already Lasers and Galvoscanners use an analog signal for control of their brightness and position. In computer controlled systems this signal is generated by a digital-to-analog converter (DAC) usually at a fixed rate of points per second (pps). The DAC is usually a micro controller which communicates with the computer. It receives a frame (= a number of points), stores it in its own memory and outputs the point info of this frame repeatedly until it receives another one. Communication is done via USB, LPT port or Ethernet. The ILDA file format is a standardized binary format to store the frames on the computer. See for example here:
http://www.acm.uiuc.edu/projects/Las...ILDAFileFormat
and here
http://local.wasp.uwa.edu.au/~pbourke/dataformats/ilda/
To display a file in the ILDA format you need an ILDA compatible software for Laser display. There are a lot of different programs out there, just search the forum a bit.
ILDA also defines a standard how to connect the DAC to the lasers and galvo scanners.
Hope that helps.

Greetings
Andreas

[Doc]

You need to buy a DAC (Digital to Analogue Controller) and a suitable software package.

Alternatively you could build a DAC and use one of the developer software packages (search "Soundcard DAC")

[bubble and tweak]

Hey guys,

Thanks for the fast reply

I am familiar with the Arduino it's an 8 bit micro controller, has pwm outs, and analog in's, so would be useful for blanking.

Would that be any use or would I need higher quality dac's, alternately you did say about the sound card which definitely has good enough dac's 24 bit 96k, would it be then a case of sending out different freq's at different decibel levels to stimulate the position of the galvos.

Or could I control a galvo through it's driver board, and just end up sending out pwm signals as well to that?

I really am sorry for my lack of knowledge, does anyone know of any decent books that might help?


Ohh and thanks again!

[bubble and tweak]

...
To display a file in the ILDA format you need an ILDA compatible software for Laser display. There are a lot of different programs out there, just search the forum a bit...

Are you talking about mamba black, and phoenix and stuff like that?

[andythemechanic]

Are you talking about mamba black, and phoenix and stuff like that?

Exactly! There are also some opensource players arround. LFI Player for example.

[andythemechanic]

Hey guys,

I really am sorry for my lack of knowledge, does anyone know of any decent books that might help?

Ohh and thanks again!

No need to be sorry, just browse the forum a bit . Most of the things you ask have been covered in numerous topics here, so if you want to learn this is the right place.

[bubble and tweak]

Hey,

I was looking at this, would this need a digital to analog converter to control the galvo's?

http://cgi.ebay.co.uk/30Kpps-Scanner...#ht_2203wt_941

I looked at a RIYA show controller, and had a look at the soundcard DAC thread on here, but not really sure still!

Do you then need a software program to send out the ild files to the micro controller?

[Pangolin]

Hi Bubble and Tweak.

Welcome to PL!

To help you understand how it all fits together, you might take a look at this article about Projector Connections:
http://www.pangolin.com/resguide12.htm

The article tells you how to make a projector that will be compatible with the ILDA Standard Projector (ISP) specification. The article doesn't give a laundry list of what you need in order to build a laser projector, but such a laundry list can be deduced from reading it, as the article tells you how to connect everything together (assuming you had everything to begin with).

If you don't have much money and you do have a lot of computer skill, you can consider creating your own software to drive it, using hardware similar to the RIYA hardware you already mentioned. If you've got more money than time, you might consider something like QuickShow, as it is a complete software and hardware package and is very easy to use:
http://www.pangolin.com/QS/index.html

Best regards,

William Benner

[ElektroFreak]

Hey,

I was looking at this, would this need a digital to analog converter to control the galvo's?

http://cgi.ebay.co.uk/30Kpps-Scanner...#ht_2203wt_941

I looked at a RIYA show controller, and had a look at the soundcard DAC thread on here, but not really sure still!

Do you then need a software program to send out the ild files to the micro controller?

A DAC allows direct computer control of the laser, which is the only way to go if you want quality imagery. Those galvos will work, but all galvos still need a signal source, which is the computer, via the DAC.

There are at least three software options for the soundcard DAC currently. Spaghetti, which is not free, but very powerful and very compatible, LFI player, which is free, plays many kinds of ILDA frames, has an awesome abstract generator and gives very smooth output, and HE Laserscan, which I find to be a bit difficult, but does work once you get the hang of it.

The soundcard DAC is a low-cost DIY option that provides 16 bit resolution on all channels, comparable to many professional DACs, analog blanking and up to 48 kpps output for galvos. It is very simple to build, also. It's intended to run around the $100-125US range including the cost of buying the software if it isn't free. It is actually very powerful, and the existing software is very capable but it is not as capable as the better commercial stuff. It lacks an easy to use live-control interface, so doing live shows is a bit difficult. If you plan to do live shows where you don't know the music or program ahead of time you'll want something like a Pangolin product as mentioned above, the Flashback 3 being an affordable and powerful option.

I don't know where the RIYA stands in terms of live control, but I do know that there is software that supprts the RIYA, including Spaghetti and LFI Player.

A tutorial for a soundcard DAC is here if you would like more information.