Topic: I want to build a DAC for Raspberry Pi 2

[James]

Have you thought about getting the exact same sound device as I use?

Try getting a USB SND8. It has the C-Media 6206 chip inside and I have never gotten one that did not work. I have made probably more than 30 LaserBoy DACs using this device.

http://www.ebay.com/itm/Sabrent-USB-SND8-8Channel-3D-USB-2-0-Ext-7-1-Surround-Sound-Box-/331237914254?hash=item4d1f51768e

James.

[emanuel]

Have you thought about getting the exact same sound device as I use?
>> yes

my soundcard is C8 and has C-Media 6206 chip inside:-(
exact the same, they do not sell, but looks equal:

ADMIN EDIT: LINK REMOVED; reason: way too long! Blowing out the window borders!


*-- SNIP --*

I'm affraid that it is not the soundcard, but what can I do...

[James]

Wait a minute!

The sound device you have pictured here: ...

http://laserboy.org/forum/index.php?topic=619.msg6598#msg6598

is not the same as the link you just posted.

The link you just posted looks to be exactly the same kind of device that I have been using and recommending for years.

http://laserboy.org/forum/index.php?topic=8.msg6336#msg6336

Don't get discouraged. You'll figure it out. You KNOW it has to work somehow!

James.

[emanuel]

is ordered, hope this helps 

[James]

Well, I bet you know how to test the new sound device when it arrives!

Right now I'm trying to build a new Linux machine.

I've got 2 x 4GB RAM and 4 X 500GB HD. It's an AMD-64 system.

I want to do software RAID 10 (striped mirror) but I can't figure out how to do it with Debian or Xubuntu.

I might have to go with something else like CentOS 7.

I don't know why the sound device you have doesn't work. Maybe it's just a bad design with a lot of cross-talk between the channels.

Something else you might want to know is how to adjust the time delay between the color signals and the galvos.

Galvos take some time to follow the input signals to the galvo amps, so you have to delay the color signal information a bit to let the scanners catch up.

You do this in LaserBoy by shifting the color signal wave samples backwards in time.

The default settings in LaserBoy are 5 samples for 48KHz waves.

If the colors are coming on too soon, you'll see flags, lit lines preceding lit segments. If the colors are coming on too late you'll see tails, following lit segments.

You can adjust the timing for each of the channels of a wave made in LaserBoy.

Go into menu b,option 3. You will see that red, green and blue are set to -5 samples.

LaserBoy can re-shift a wave that you have already made without having to make it all over again. It saves the sample offsets in the header of the wave.

James.

[emanuel]

http://www.prontosystems.org/tux/software_raid


(software raid under debian) page is in german, but translating in google works well.

[James]

Thanks. I think I got it.

I'm going to use 5 x 500GB HD in a RAID5.

I made a bootable USB stick Xubuntu. So I can go into live mode and do all the mdadm stuff before I install it.

I just ordered a nice video card that can do 4K.

Pretty soon I'm going to get a 65 inch curved screen 4K monitor.

I'll be able to run LaserBoy at 3840 2160 !!!

That's just SICK!

James.

[emanuel]

I'm gonna Ilda editor newly ...


That's still a python script 

[James]

That's a very interesting methodology you've got there.

Looks good!

Thanks for posting that.

You know you can have your own thread in Laser Software ...

http://laserboy.org/forum/index.php?board=26.0

James.

[emanuel]

Yesterday I tried the new soundcard. What can I say. The spirit rotating effect (here magenta) with blanking lines was even stronger, lighter and even faster than with the old sound card. My first thought: I'm going to have to dig deep into my laser projector, the home power supply ... The first thing I was looking for material in the basement, so I can build me a Wire cable between the amp kit and the laser to achieve single DB25 contacts operation. And I have an old printer cable ~ found 5 meters and an old software dongle. Profit after about 1 hour soldering was a 5m DB25 extension cable. (RGB channels are not soldered to test). Now the red gear to the test. goes well, no more issues. The green gear was I think yellow and blue was magenta and had all blanking to lines. But the rotating effect spirit was gone.


Errors were: channel I was exchanged for a color channel, the amp kit directly connected to the projector without shielded cable has interference (ghost Effect) So I think the other 2V + sound card works just as well. To find the bug without oscilloscope is difficult in such a small fast signals. I tested on the Raspberry, today I have connected the correct cables, and for the first time a reasonably clean image (only tested with default settings in Laserboy)


In the python script I will sometimes try to produce music signals, perhaps going yes.


see:


https://goo.gl/photos/8stdcCFv57FkyE9e9


 

[James]

That does look much better!

It looks like you need to slow down the scanner velocity by lowering the number values of options 3 and 4 in the [Tab] menu.

You might also experiment with the sample shifts between the galvo signals and the color signals.

It looks like the lasers are either coming on too soon or too late.

You can really see the effect of scanner to color time alignment if you make a 10 second still image of frame 14; the star field (lots of white dots).

If your timing is off you will see all kinds of streaked lines.

I bet you could figure out a way to make a frame that would tell you whether your scanners are early or late!

Good work, man!

James.

[emanuel]

Ok, I'll try


-> News about my new beta: see picture, toolbars are ready (hand made, tkinter do not provide by default) 

[James]

That's pretty cool!

You are welcome to start a new thread in the Laser Software section of this forum.

Did you look at any of the LaserBoy code and see how I made all of the classes that make all of this stuff work?

James.

[emanuel]

Yes little bit, but python is very diffrent from C/C++.
I've looked a lot in the effects of lb, and in the ilda specifications (pdf) here in the forum.

[emanuel]

Orange is working (ild file from net) converted by lb.


https://goo.gl/photos/2TKubngAymxaEeVG6


Thank God I've found Laserboy