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Peachy Printer - The world's first $100 3D Printer

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Re: Peachy Printer - The world's first $100 3D Printer

#41

Post by oakwhiz »

jlgreco wrote: post #18
kevingadd wrote: post #13

Earlier quoted context omitted.

I'm not referring to 16 bit precision per sample, more to 44khz and the potential for multi-millisecond audio glitches on most modern PC configurations. Glitch-free audio is pretty tough, still.

Perhaps, with slightly more hardware, you could rig it up to kill the power to the laser if the sound level dropped to zero (which is typically how computer audio hiccups manifest). Printing would stop for a moment, but you wouldn't have the laser curing anything it shouldn't.

This doesn't really work, though, because to the 3D printer, 0 volts is a valid signal in the domain of the input. Never use a value in the domain of your input as a null value. Additionally, it is difficult to define what the sound level of a continuous signal really is, since it is usually computed using an averaging, integrating, or low-pass filter (not sure which.) Just like an old-fashioned VU meter, it takes a moment for the needle to fall down to 0. By the time this happens, the glitch is over.

Also, consider that not all audio glitches are of the type that cause zeroes to be emitted. Some audio glitches are known as buffer underruns, where the ring buffer holding audio is not filled up in time, and eventually runs out, causing the same few milliseconds of audio to play over and over again until more audio makes it into the buffer.

Re: Peachy Printer - The world's first $100 3D Printer

#42

Post by beambot »

SwellJoe wrote: post #15

This is the first 3D printer I've been excited about since the very first one I saw maybe a decade ago. The reason is that it is actually a novel approach that I can see is in its very infancy...and it's clever as hell. The reality of 3D printers is that at this stage of their development, they aren't useful for a lot of people; at least not useful enough to make them a cost-effective purchase. This, however, begins…

Those galvos don't look very accurate (at least not without a lot of calibration and low-tolerance manufacturing). But who cares... its a $100 3D printer! I'll buy one -- but only once it's ready to ship.

Re: Peachy Printer - The world's first $100 3D Printer

#43

Post by jlgreco »

oakwhiz wrote: post #41
jlgreco wrote: post #18

Earlier quoted context omitted.

Perhaps, with slightly more hardware, you could rig it up to kill the power to the laser if the sound level dropped to zero (which is typically how computer audio hiccups manifest). Printing would stop for a moment, but you wouldn't have the laser curing anything it shouldn't.

This doesn't really work, though, because to the 3D printer, 0 volts is a valid signal in the domain of the input. Never use a value in the domain of your input as a null value. Additionally, it is difficult to define what the sound level of a continuous signal really is, since it is usually computed using an averaging, integrating, or low-pass filter (not sure which.) Just like an old-fashioned VU meter, it takes a…

I'm thinking you would throw in a cheap microcontroller and basically use it as a modem to control the printer. If the carrier signal is lost, then it stops printing. This would retain most of the benefits of using the audio jack, including being able to re-compute prints and play them back with something like an mp3 player instead of a proper computer.

Re: Peachy Printer - The world's first $100 3D Printer

#44

Post by DerpDerpDerp »

kevingadd wrote: post #30
anigbrowl wrote: post #25

Earlier quoted context omitted.

That's not true at all and hasn't been for a long time. Maybe if you're mixing more than 8 tracks on a low-power CPU, but even a chromebook can do that sort of thing. Even my phone (several years old) can do that. Playing back stereo audio (which all that's required here) is something that can be done from a device that fits on your keyring. What you're arguing hasn't been true since the 90s. Certainly, it would be b…

I'm not talking about 'can you play back audio', I'm talking about 'can you play back audio with zero glitches'. This becomes a problem of scheduling precision, whether or not scheduling will 'stall' if a driver hangs while processing an IRQ, whether or not the graphics driver has a potential to hang due to a rendering operation, etc, etc. These are all a reality on modern desktops even if they're fairly rare (I don'…

People making hardware focused on audio typically use real-time operating system versions, because of the schedule requirements imposed by the audio sampling.

Re: Peachy Printer - The world's first $100 3D Printer

#45

Post by oakwhiz »

jlgreco wrote: post #43
oakwhiz wrote: post #41

Earlier quoted context omitted.

This doesn't really work, though, because to the 3D printer, 0 volts is a valid signal in the domain of the input. Never use a value in the domain of your input as a null value. Additionally, it is difficult to define what the sound level of a continuous signal really is, since it is usually computed using an averaging, integrating, or low-pass filter (not sure which.) Just like an old-fashioned VU meter, it takes a…

I'm thinking you would throw in a cheap microcontroller and basically use it as a modem to control the printer. If the carrier signal is lost, then it stops printing. This would retain most of the benefits of using the audio jack, including being able to re-compute prints and play them back with something like an mp3 player instead of a proper computer.

This does make it a bit more complex though, because the microcontroller, though simple, still needs a board and some kind of power supply, and a reasonably accurate DAC for controlling the galvanometers. The microcontroller would have to spend the time in between DAC timer interrupts to perform the "modem" function. Not too bad since for this project the DAC only needs a frequency of 8kHz or less, but still mildly challenging. You could just use an RS-232 or USB interface instead of trying to create a modem since that would be easier and perhaps more reliable.

Re: Peachy Printer - The world's first $100 3D Printer

#46

Post by reustle »

jlgreco wrote: post #28
scoofy wrote: post #10

This is a bit too good to believe, but at $100 i'll bite. I've been into 3d printing for years now, and my main concern is material. If this resin is durable, and doesn't get soft in the car on a warm day, this design could be really groundbreaking. If not, it'll be a waste of everyone's time. The quality looks pretty decent given how awful low end 3d printers can be without a ton of tinkering. My current printer cos…

It looks like the resin they are using is "Makerjuice" ( http://makerjuice.com/ ). I don't know anything about that resin though.

$40 for one liter of red, that doesn't seem too bad.

Re: Peachy Printer - The world's first $100 3D Printer

#47

Post by SwellJoe »

kevingadd wrote: post #30
anigbrowl wrote: post #25

Earlier quoted context omitted.

That's not true at all and hasn't been for a long time. Maybe if you're mixing more than 8 tracks on a low-power CPU, but even a chromebook can do that sort of thing. Even my phone (several years old) can do that. Playing back stereo audio (which all that's required here) is something that can be done from a device that fits on your keyring. What you're arguing hasn't been true since the 90s. Certainly, it would be b…

I'm not talking about 'can you play back audio', I'm talking about 'can you play back audio with zero glitches'. This becomes a problem of scheduling precision, whether or not scheduling will 'stall' if a driver hangs while processing an IRQ, whether or not the graphics driver has a potential to hang due to a rendering operation, etc, etc. These are all a reality on modern desktops even if they're fairly rare (I don'…

I'm an audio nerd; I went to school for it, and I'm back to working professionally in the field (after a 15 year hiatus where I did it as a hobby). Serious audio problems do still exist on Linux systems, and it is a source of huge annoyance for me that my system still causes my (very expensive) studio monitors to pop when switching between some sound sources in some situations. But, these are mostly to do with the sound server and switching sources rather than with glitches in actual audio.

I still can't use Linux as my primary OS for audiovisual work because there are still issues with getting many channels of low latency, high resolution, audio playing and recording reliably.

But, the issues you describe as they apply to this task are mostly a long solved problem, at least for very simple tasks, like reliably playing 16 bit, 44.1 kHz, stereo audio. Honestly, there's never been a time that I can remember when I couldn't reliably play a stereo 16 bit, 44.1k, file back on a Linux system...going back to 1995, or so, when I first started using Linux. The problems come when you demand a little more of the system.

Once again, errors of the level that exist today (which are completely inaudible to even trained ears in most cases), in terms of latency, jitter, dropouts, etc. are so tiny and insignificant that they would be impossible for the current hardware to replicate. The hardware is so much slower than the input signal that noise from the audio signal will be lost in the much larger noise of the hardware. You can see the hardware noise in the printed objects. It's vastly larger than anything the computer output is going to screw up, and it'll be many generations before that stops being true (and, by then, maybe Linux will finally have its act together on audio).

Windows, BTW, finally does have its act together on audio, and has for five+ years. I can reliably play a couple dozen 96k 24 bit tracks while recording more on slightly high end laptop. Obviously Mac is also solid on this front.

Re: Peachy Printer - The world's first $100 3D Printer

#48

Post by Kliment »

WestCoastJustin wrote: post #8

Kickstarter link @ http://www.kickstarter.com/projects/117421627/the-peachy-pri... This is such a cool concept -- I backed it! I do not want to highjack the conversation, but I think it is worth mentioning, that this is kind of a "grinds my gears" [1, 2] moment when someone links to a summery, which borrows the video and images of a Kickstarter campaign, you are essentially diverting the campaigns traffic, why not ju…

3ders is a summary site. All their articles are on this level. And yes, they are scummy like this with most of them.

Re: Peachy Printer - The world's first $100 3D Printer

#49

Post by rorrr2 »

jlgreco wrote: post #28
scoofy wrote: post #10

This is a bit too good to believe, but at $100 i'll bite. I've been into 3d printing for years now, and my main concern is material. If this resin is durable, and doesn't get soft in the car on a warm day, this design could be really groundbreaking. If not, it'll be a waste of everyone's time. The quality looks pretty decent given how awful low end 3d printers can be without a ton of tinkering. My current printer cos…

It looks like the resin they are using is "Makerjuice" ( http://makerjuice.com/ ). I don't know anything about that resin though.

$40/liter for small prints

$45/liter for large

Not cheap if you want to print anything larg-ish.

Re: Peachy Printer - The world's first $100 3D Printer

#50

Post by bookface »

scotty79 wrote: post #29

Awesome idea. But isn't mirror inertia a problem? Also constant velocity of z-axis movement might pose some inefficiencies because if you want to print a box you have to set the rate of ascend low enough for the laser to create full bottom and you can't speed up when you are building sides of the box.

Just print the box titled a few degrees :-)
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