Raspberry Pi

[james]

Oops!

Just found a bug in the previous release.

http://laserboy.org/code/LaserBoy_2013_04_16.zip

I think this fixes it.

James.

[james]

Update:

I plugged in my LaserBoy DAC, aka C-Media 6206 based USB sound device modified for DC coupled output. (plugged into my Raspberry Pi)

At first, I didn't think it was working correctly, but then I realized that the channel assignment is different from Windows. Channels 5 & 6 are swapped for channels 7 & 8. So when I played a standard 6 channel LaserBoy wave, I had no blue or monochrome signals. But then I switched the wires coming from the sound card, going into the correction amp and now I have everything right where it should be!

Now the only problem is that I see quite a bit of clipping on the galvo signals. When I play a wave of a circle that fills the display area, it's quite out-of-shape. I tried backing down the levels of the front left and right audio channels using alsamixer, but that doesn't fix it. It just makes the distorted circle smaller. If I crank the levels up beyond a certain threshold, it gets much more clipped into a big square.

If I display regular graphics that don't take up the whole display area they look fine!

So at least I have that.

I also notice that moving the mouse in X causes glitches in the laser display.

I think I need to look into shutting down every service that is not absolutely necessary.

James.

[JohnYayas]

Update:

I plugged in my LaserBoy DAC, aka C-Media 6206 based USB sound device modified for DC coupled output. (plugged into my Raspberry Pi)

At first, I didn't think it was working correctly, but then I realized that the channel assignment is different from Windows. Channels 5 & 6 are swapped for channels 7 & 8. So when I played a standard 6 channel LaserBoy wave, I had no blue or monochrome signals. But then I switched the wires coming from the sound card, going into the correction amp and now I have everything right where it should be!

Now the only problem is that I see quite a bit of clipping on the galvo signals. When I play a wave of a circle that fills the display area, it's quite out-of-shape. I tried backing down the levels of the front left and right audio channels using alsamixer, but that doesn't fix it. It just makes the distorted circle smaller. If I crank the levels up beyond a certain threshold, it gets much more clipped into a big square.

If I display regular graphics that don't take up the whole display area they look fine!

So at least I have that.

I also notice that moving the mouse in X causes glitches in the laser display.

I think I need to look into shutting down every service that is not absolutely necessary.

James.

I heard that if there is a problem with the output of the soundcard DAC it is because the user doesn't know how to use it.

[james]

I would imagine that is absolutely true. With Linux there is always a way.

At the moment, I have no way to tweak the device driver. This distribution of Raspbian Wheezy does not come with the Linux kernel headers or module code.

I'll figure it out. I think moving the whole project to a dual or quad core running at 1.2 to 1.8GHz with 2GB of RAM would make a huge difference.

James.

[JohnYayas]

I would imagine that is absolutely true. With Linux there is always a way.

At the moment, I have no way to tweak the device driver. This distribution of Raspbian Wheezy does not come with the Linux kernel headers or module code.

I'll figure it out. I think moving the whole project to a dual or quad core running at 1.2 to 1.8GHz with 2GB of RAM would make a huge difference.

James.

On Linux all devices are files so just open a file and send the data to it. I can't imagine it is any harder than that.

[james]

Again, that is basically true. However there are some IO control calls that need to be made to the file that set up the driver for things like data type, sample rate, number of channels, and the individual output levels of the channels.

I just got it to work today. I'll fine tune it.

Thanks for paying attention Gary. Maybe you should get into Linux so you could actually see all of this for yourself.

James.

[polishedball]

Steve if ADAT is useless I'd be happy to buy your stash of old ADAT show tapes.

[Bradfo69]

^^What he said. I have two modded ADAT machines ready to go, and have never even seen a tape in person.

[james]

Did you mod both the ins and the outs?

If you modded the ins, you can record the output of any laser DAC. Get a computer sound device that takes ADAT LightPipe. Then you can transcribe your recordings to hard drive and make them into multi-channel waves. Those waves will open as full color vector art in LaserBoy!

[james]

Briefly looked at this thing. Should be able to make a hell of a DAC out of this thing. Might be the first DAC you can plug a keyboard, mouse, and a monitor into and surf the web while projecting laser images.

Hey Gary!

You started this thread and you now have exactly what you predicted.

Have some fun with it.

James.