Why Sound Waves - Why NOT just data?

[Compro01]

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?

Ever notice how some of the earphones included with smartphones has a microphone in it? Most smartphone "headphone" jacks are actually TRRS connectors. They function as both headphone jacks and microphone jack.

[Slatye]

Hmm, I wonder whether you could use the phone's camera instead. Just mark the container at, say, 10mm increments (for calibration), and then point the phone at it. Easy to use a threshold to detect the resin (assuming it's one of the brighter colours), and that gives you both the water level (bottom of the resin layer) and resin volume remaining (total height of the resin layer). The advantage would be that it provides an absolute height - whereas the microphone method is an integral and may or may not suffer from drift.

[BrockMcKean]

@Compro01. Ah! I see. I wasn't aware of this. I don't know very much about peripherals of these kinds of handheld devices, but I guess it makes perfect sense with products like Square's card reader and PaypalHere. I wonder if the noise is approximately the same on phones, and from phone to phone? I know in many laptops the output and input can be very noisey depending on whether it is plugged into a charger or not. If this is a real concern, to print identical objects with identical resolution from multiple devices, more hardware and a filter would be necessary.

@Slayte. Using the phone's camera would largely depend on several things that would be basically impossible to configure identically. Consider the following:
1) Position of the lens is not identical across most phones. You would have to have a way of ensuring the camera was positioned identically every time you began a print. This would mean a physical device to ensure it is physically some defined distance from the printer and oriented identically as well, probably orthogonally. You could attempt to account for the differences in position and orientation through software, but it may not be possible depending on the distance and orientation of the camera. Some extreme examples would be if it was pressed directly to the print area so that the entire reservoir was outside the scope of the image, or if it was turned away. Even neglecting these rather macroscopic concerns, if the resolution of the printer are to approach several hundred micrometers, this is tenths of a millimeter. 200 um = .2mm, so your 10mm markings would have to turn into 0.1mm markings.

2) Quality of the image and/or video is not the same. Most newer smart phones are ~20MP, but not all are this quality and some regular cellular phones are significantly lower. I'm not going to go into a physics and geometry explanation of this particular problem, but basically MP is a measurement of how many millions of pixels a camera produces in a single image. For a given object at a given distance with a given number of MP, you have a resulting actual size pixel dimension. This means, one phone may see 0.1mm where another phone may see 0.2mm depending on all of these things, assuming it is even high enough resolution to see 0.1mm markings and when liquid rises beyond it. The same problem of reading a beaker or graduated cylinder (the miniscus) would be present here as well. The surface tension of the resin would cause the mixture to cling to the sides and this would likely make it very hard to read in 0.1mm increments.

3) Lighting changes reflective properties of objects, especially liquids. As you noted, you may have to use a colored resin for this kind of approach. What if your resin is red and the background is red? What if the lighting is such that the surface of the liquid is very very hard to see? For example, in ultra low light conditions when you turn your lights off and the print continued?

There are too may design problems to correct with this method, in my opinion. Not to mention the same phone, and nearly all phones use this same TRRS connection Compro mentioned. The prints would be wildly unreliable and differ greatly for each camera device used.

[Geoff]

I actualy thought about this just right now,
Will we be able to use speakers to listen to music as its printing? (Even tho we have 2 3.5mm audio jacks.)
I am guessing not? ^^

You know it's going to sound like your commodore64 tapes loading!

[Compro01]

I actualy thought about this just right now,
Will we be able to use speakers to listen to music as its printing? (Even tho we have 2 3.5mm audio jacks.)
I am guessing not? ^^

Just hook up a Y connector.

[nka]

Y wont work.. you can't play music while printing, except if you have a 2nd sound card, like a USB SoundCard.

[Compro01]

Y wont work.. you can't play music while printing, except if you have a 2nd sound card, like a USB SoundCard.

Nevermind. I was misreading what Dr. Luigi was saying as a result of what Geoff said. I was thinking Luigi was saying something about listening to the sounds the printer is operating off or something.

[nka]

Oh!

But with a Y, you could print 2 time the same things at the same time!

[Slatye]

I've been uploading a bunch of videos of my Makibox printing, and YouTube keeps taking them down because apparently they sound like copyrighted music. Maybe the Peachy will be the same, but it's even easier to record the music it produces!

It'd be an interesting bit of steganography - who can design an object that results in the Peachy software generating music? Can the object be banned for copyright infringement?

[rylangrayston]

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.

Very well worded, infact our instructions will say exactly this!