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FrozenGate by Avery

Laser scanner help

Joined
Jan 26, 2009
Messages
16
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Hello everyone,

I will start off by saying I am a software engineer, and do not have much experience with electronics or embedded software. I did manage to get a working 405nm build in a flashlight host exclusively thanks to the great people of the laserpointerforums community. It worked for a while, then I accidentally left the clicky cap on for a few hours (I thought it was off) which killed it....

I wanted to try my hand at working with laser scanners, more specifically through the ILDA port using custom software I will write.


I am not sure I have a full understanding of all the parts required though.

Galvo System
20KPPS Hightspeed Galvo Scanning System MAX35KPPS Including Show Card | eBay
Laser Module
150mW 532nm Green Laser Module with Heatsink | eBay
DAC
????????

Do I need any other parts to make this work?

The link to the galvo system I posted claims to have a showcard, is this the DAC? Can I modify the card to connect through USB to my computer? I saw some existing USB DAC products but they were unbelievably expensive, can someone tell me why? I also saw that a popular method was to hack a usb soundcard to perform as the DAC but this method seems to be difficult to maintain and prone to errors. I don't want to pay an arm and a leg for a device that simply converts my digital signal to a voltage. Am I missing something here, or is that technology normally expensive?


Assuming I could get it all connected together I should then be able to write a driver for the usb DAC, as well as a programming interface which uses the driver.


I am pretty sure some of my understanding is incorrect for certain things, please correct me where I am wrong.


Thanks a lot!
 





There is arguably a DAC in the showcard, but it isn't usable for anything except the patterns stored on the board as far as I know. The DACs for laser show use aren't expensive because of the hardware. As you say, all they really do is convert a digital signal to a voltage. They're expensive because they come with software. If you're looking to write your own, I suggest going the soundcard DAC route.
 
I'd suggest the soundcard DAC route as well. It's a pretty high-speed multi-channel DAC and you can control it directly with a computer as a sound output. It'll be a good place to start. The DACs on most MCU boards (e.g. Arduino, Beagleboard, etc.) are usually too slow, and you'd have to wire up a DAC that interfaces with the SPI output to make something decent.

Alternatively, you could buy something like a dedicated laser DAC that has a public API and try programming that. It'll cost substantially more than a soundcard DAC.
 
You can buy iShow, the cheapest and crummiest software one can buy with a DAC. You could then use the ILDA port to direct drive, so to speak, the galvos.

But, with the switches set properly, it may power up and start walking through patterns, which you can see in the servos. If you get that far, meaning, getting that much working WITHOUT the laser, you are them ready to add the laser and see what you can see it do.
 
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You could try Lasershark. It's an opensource laser DAC. The only drivers so far are for OpenLase. Openlase is a open source library built on the Jack audio connection kit. I've got mine up and running with 1 color so far. The next step for me is adding 2 more lasers and then replacing all the TTL drivers with analog.

I've read many times not to waste your time with iShow.

Edit: Added pictures
Sorry for the glare it only showed up in the pictures. It was a little to close when I took them.
7813-made-tracing-video-using-openlase-playvid.png

7815-a.png

7811-a.png
 
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