Why Sound Waves - Why NOT just data?

[JamesCooper]

As you can imagine, the sound card won't be able to play music while it's busy printing (it won't even be plugged into the speakers at the point), but if you want, you can still play your music by using multiple sound cards. You can get a USB sound card for as little as $5. You can also use other devices to play music, such as your smartphone or CD player.

[nka]

JamesCooper: Will the software "take over" the sound card to prevent any sound? Like if you receive an email ?

[JamesCooper]

That's a great question. I don't think that's actually something a program has a choice over -- the OS typically deals with mixing multiple audio streams into a single output. I'll keep in mind to see if there's a way to force exclusive output, but I'm confident that there isn't a portable way to do it -- certainly not with the PortAudio portable audio library I'm currently using. I know Linux and Windows both have relatively simple interfaces for the user to mute other programs and system sounds. You can also programs to play to specific audio devices (not necessarily the default), so a second sound card would again be a way to ensure that isn't a problem.

[Slatye]

Just curious - is there any way to have the Peachy utilise some of the unused channels on most soundcards? Pretty much every soundcard (or mainboard with integrated sound) has at least six channels these days (eight is more common) and yet a lot of people only use two (headphones or standard 2-channel desktop speakers). Could the Peachy just grab some of the channels that are meant to be for surround-sound speakers and leave the main two channels for everything else? That way you could keep using the soundcard while the Peachy was working.

[JamesCooper]

Slatye: It looks like it might be possible in some cases, but not in a general, portable way. Windows seems to give you the option of specifying which channels to use, which would allow you to play on only the rear channels, while programs would normally request only the stereo (front) channels. At the same time, if Windows was configured for 2 speakers, it would copy the front to the rear, defeating the purpose, so people would have to configure their computer appropriately. SDL has support for surround sound, but it doesn't allow using only a subset of channels. I suppose Peachy could just avoid playing on the front channels, though there's still no way to ensure another program isn't writing to those rear channels).

Honestly though, this is much ado about nothing. Expect that the Peachy will require the dedicated attention of the sound card while it is printing. If that's a problem for you, I recommend buying a cheap USB sound card.

[nka]

USB soundcard seems to be the best solution. Or even better with a Microcontroler!

[Anuvin]

Another solution for those running Windows Vista, 7, or 8 is to right click the Volume icon in the taskbar while potential sources of sound are in use (example: watching youtube with your broswer, listening to music with windows media player, etc). From there you can open the Volume Mixer, and adjust an individual program's volume. Just set your browser, video games, music, and flash player to mute, and you are all set to do whatever you want while your system prints.

[Pete]

Really excited to be a part of the Peachy as a beta backer. I'm especially interested in the electronics now it has progressed from a DC coupled soundcard into some circuitry with an AM demodulator and I'm wondering if you've somewhat overestimated the cost and benefits of a complete micro system compared to what you now have....

I've had some previous experience with STM32 micros and I've currently got my eye on the STM32L100R8T6 which is under £1 (+ resistor, linear reg, crystal, a handful of caps and resistors) and would provide you with USB data connection and two 12Bit DACs onboard (I suspect you would want cheap buffer amps to drive the mirrors). It should be relatively easy to get a few 10's of kpoints/s on each DAC channel from USB you would also then get all the device controls via this mechanism; control for laser, drip feedback, calibration storage on device.
This might also offer an easier upgrade path for the basic unit, it would be easy to incorporate on the PCB but not populate a better DAC, SD storage, LCD status, user controls/feedback etc.
This of course could work with Smartphones and Tablets that have USB host capability which are becoming far more common.

[BrockMcKean]

I thought the entire system was dependent on microphone feedback from a capacitive sensor that discharges every time the resin drips through? How will it work well via smart phone if it does not have the separate I/O channels to control the laser and the resin level? I assume it's not needed if the drip reservoir is a specific shape and volume but I thought that was intended to be a separate part and not included with the kit?

[Anuvin]

I think it works by reading a certain part of the 3.5mm phone connector.