ILDA standard question

[Experimentonomen]

Another good budget dac is the norm´s usb dac, search for norm´s laser show on google, look for "FrameStreamer Express II"

[bubble and tweak]

Hey guys,

Now I'm looking into the hacked soundcard method and wondering if 5v analog blanking is different to ttl blanking.

Cheeers

[Experimentonomen]

Analog is like a dimmer while ttl is like a switch.

[ElektroFreak]

Analog modulation is superior to TTL, but it is only useful if your laser(s) also support it. If you're using TTL lasers with an analog DAC, they still behave like TTL (on/off only). Since analog allows for precise(ish) output power control, it is possible to smoothly blend colors and/or perform fades in or out. In a full color RGB system, the difference between TTL and analog blanking means the difference between 7 color possibilities and up to 16.7 million color possibilities.

[bubble and tweak]

Analog modulation is superior to TTL, but it is only useful if your laser(s) also support it. If you're using TTL lasers with an analog DAC, they still behave like TTL (on/off only). Since analog allows for precise(ish) output power control, it is possible to smoothly blend colors and/or perform fades in or out. In a full color RGB system, the difference between TTL and analog blanking means the difference between 7 color possibilities and up to 16.7 million color possibilities.

Holy niagras!

That is cool, I am no where near that sort of stage, I just want one laser and a bit of graphics.

In the ILDA format it must contain x and y information for each point that is projected, is this done by sending out different voltages?

[ElektroFreak]

That's exactly right. The galvos use signals not entirely different from audio speakers, and if the waveforms are just right, shapes and forms can be created. Galvos are analog, but they incorporate feedback so that they always move around a center point. This allows the galvos to collectively plot points in x/y space based on each one's position relative to center.

[bubble and tweak]

That's exactly right. The galvos use signals not entirely different from audio speakers, and if the waveforms are just right, shapes and forms can be created. Galvos are analog, but they incorporate feedback so that they always move around a center point. This allows the galvos to collectively plot points in x/y space based on each one's position relative to center.

Right so let me get this straight:

Computer outputs data through the serial port --> DAC then converts into Eq Voltages for each channel --> Fed into Amplifier -->> Amp to Galvo drivers -->> Drivers to Galvos.

Is that the setup usually used?

I am getting confused with all the boards that are out there and my inability to work out what amp is needed to drive the buggers.

I looked at spaghetti and it states a few boards that it is compatible with one being:

http://www.usbmicro.com/products.html

Is that product essentially used as a DAC, is this what you can connect to your computer and fire the ILDA data into, which then goes to an amp?

[ElektroFreak]

Your breakdown is pretty much correct except that initially the computer outputs data via a USB port rather than serial.

You shouldn't need anything like those USB development tools, no. The soundcard DAC has USB connectivity built in if you use the suggested USB sound card. Commercial DACs will either have USB or network connectivity, or they can also be a card that goes directly in the computer.

If you buy a commercial DAC, you don't have to worry about any amplifiers since the galvo amps come with the galvos when you buy them and you only need a "correction amp" board if you're building a soundcard DAC. A commercial DAC is simpler to use than the soundcard DAC, but also more expensive.

Basically it goes like this:

Computer => DAC => Galvo amps and lasers. In the case of the soundcard DAC, the correction amp is part of the DAC itself and is not necessary at all if you're not using a soundcard DAC. If you look at the soundcard DAC tutorial I linked to there is a wiring diagram. You can see where each output goes in that diagram. Every DAC available, whether it's DIY or commercial, has these same outputs.

The whole thing can be pretty confusing even with commercial DACs, but with time and questions will come understanding..

[bubble and tweak]

Your breakdown is pretty much correct except that initially the computer outputs data via a USB port rather than serial.

You shouldn't need anything like those USB development tools, no. The soundcard DAC has USB connectivity built in if you use the suggested USB sound card. Commercial DACs will either have USB or network connectivity, or they can also be a card that goes directly in the computer.

If you buy a commercial DAC, you don't have to worry about any amplifiers since the galvo amps come with the galvos when you buy them and you only need a "correction amp" board if you're building a soundcard DAC. A commercial DAC is simpler to use than the soundcard DAC, but also more expensive.

Basically it goes like this:

Computer => DAC => Galvo amps and lasers. In the case of the soundcard DAC, the correction amp is part of the DAC itself and is not necessary at all if you're not using a soundcard DAC. If you look at the soundcard DAC tutorial I linked to there is a wiring diagram. You can see where each output goes in that diagram. Every DAC available, whether it's DIY or commercial, has these same outputs.

The whole thing can be pretty confusing even with commercial DACs, but with time and questions will come understanding..

You sir are an absolute legend, I'm sorry i was refering to usb when I said serial, as I thought it was a universal serial bus, and in the arduino that's what you say when you want to send data out ie Serial.print

I think I am going to go along with the method you suggested, get it all working then try and work out how to build my own dac.

btw what correction amp did you use for your project?*

sorry found it on the page... erm I'm a moron sometimes!