Quote Originally Posted by User_Defined View Post
Youd have your input signal with a voltage proportional to what angle the mirror would be.
Next it would go to your amplifier circuit to drive the mirror.
From the mirror you would then have a positional measurement by the magnetoresistive sensor.
The error is defined by where the mirror actually is, and where you wanted it, and this signal is fed back to combine with the original signal to close the loop and subtract away the error. A system like this should auto dampen.
Yes, it would take care of any distortion in actual mirror position due to noise, or vibrations. However, what about the printing material itself? Just because you dampen the mirrors doesn't mean the resin isn't bouncing around. The resin has to be physically dampened somehow. Also, there are plenty of hall effect sensors that can be used in parallel as you are describing and in series with the coils as well. Not entirely sure what's different or special about that particular sensor from Honeywell other than the low power requirements.

Quote Originally Posted by Aztecphoenix View Post
The old ZX Spectrum computers were designed to use any tape deck that you had available rather than a model specific deck and took in the audio signal and converted it into binary code
This is possible, but doesn't really make any sense to do. If you have a sound port on a device that is capable of running the peachy's software, it should have a USB port as well. To go from analog to digital and back to analog you're going to need some sort of "processor". Which means that you honestly might as well just use USB. The problems that arise from different sound cards range from different noise levels to different output levels. Analog is precise, meaning the signal must be exact. Digital allows for a lot of wiggle room. There's no way to build a circuit that will always be compatible with every sound card. Plugging a laptop in will usually produce some noise on the line, resulting in a distortion in AM. Some sound cards that are on-board desktop cards have a significant amount of noise on them as well. If you own a phone that wasn't taken care of as well as it probably should have been it will likely not produce sound without some minor distortion that may be inaudible, but will affect AM.