He has already worked on something very similar, however I don't think that he has gotten a super cheap and easy to make valve to work well yet. I could be wrong though.
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If the point is to keep the cost as low as possible and it's reasonable to do something that would decrease the cost I don't see why it shouldn't be done. If the mirrors truly operate on AM, FM should not affect them at all. But if we did want to add a filter before it, it would guarantee that no FM would ever reach the laser assembly. Adding somethign like that will cost basically nothing, pennies. Placing a low pass filter before the peachy's mirror/coils would completely isolate it. Using an op-amp to, connected to the 5V for DC bias, and passing the frequency from the audio jack, the coil can be controlled directly. I guess it sounds a little complicated, but I assure you things like this (using multiple and separate modulation schema) are done all the time in many electronic devices.
Yes I know that using multiple modulation is common and relatively simple. However I am skeptical here that this will not cause issues by trying to do too much at once. Very little can throw off things when stuff is controlled directly by varying voltage levels as the mirrors are. Also if USBs are already used for power, why can't they just control this too? I think using the USB would be cheaper anyway. I am still not totally clear on the details of how everything is powered, but yeah I think using the USB is the way to go.
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Yes, I agree. It shouldn't stay open. This means we need a switch between 5V DC and Ground, or some way of using the AC signal directly from the audio output that will result in the desired movement. Maybe we can use PWM over USB instead if we are going to use it for a DC bias directly from the device anyway. This would probably be easier and certainly separate if it can be achieved at the correct voltage/current level on the data line USB data line.
Exactly. Although it doesn't have to be pulse width modulation necessarily, just a pulse whenever it wants! Although I assume this is what you mean. As for the voltage and current I am very confident this can be made to work.
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Unless the magnetic field is on the entire time and the desecent of the magnet is forced and controlled, there's no way to guarantee that freefall will not result in the magnet ending up lop-sided, assuming there is pressure above the magnet still. However, if it has some sort of guiding rod to prevent it from turning to that kind of angle that extends from the magnet up/down the drip a bit it should be no problem.
I disagree. I think this is a non-issue for multiple reasons. First if the solenoid gets pulsed for a tiny amount of time then the magnet rubber ball object plug won't have time to rotate. However let's say that instead it is pulsed for a long period of time, like in the videos that I showed. Say then downstream of that a narrow opening is used so that the tubing still has drops come out. In this case there still will not be an issue because the rotation forces caused from asymmetries of the water passing through the valve will not be enough to rotate it, even will some pressure. Also if there is minor rotation this is fine. The ball is a sphere of course, so even if it is rotated some it will still plug the hole the same way. If you are still worried about it then if the magnet/iron is thick enough and close in diameter to the PVC adapters inner diameter it won't be able to rotate. And in addition to this if there was still problems then people could figure out what is causing crazing rotational forces and maybe have the solenoid semi powered when the magnet/iron is falling. So yeah there are a lot of reasons this is not worth worrying about.
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Yes, but then you also have to worry about the reservoir's resin level. I'm not really sure how the drip works now exactly (at all really), but any resin below the valve would have to be pumped to the valve somehow or the reservoir would have to mechanically change to deliver the resin. So if this is not a problem it should be placed as high as possible.
I should have been more clear here. When I said "as high up as possible" I meant taking this into account. If the salt water is dripped in then the valve will have to be below any water that it going to be dripped in eventually. If the salt water is slowly dripped out (as would be done if the salt water + resin + fresh water printing method is used) then the pump will have to be below the lowest point that the resin gets when the print is finished (which is when the resin is in its lowest point).
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If the drip governor can only move to one position we're limited to altering the period for variability, which is fine and probably the best approach. However, the dynamic range will then be determined by the minimum amount of time we can open the valve. Accuracy is not a problem here, but if we want to be economical about it, the software should take the drips into account and calculate the resin level without measuring afterwards (because the drip resolution and number of drips are known, the entire volume is known). This would require using a well defined right rectangular prism as a reservoir (all opposing sides parallel, all adjacent sides perpendicular) so that the area for each level is identical. I'm not sure if that's part of the peachy's design right now or not to use some sort of level measuring method, but calculating it this way would be much less invasive and not disturb the print surface/material in any way and would allow for more printable volume.
I think that measuring after the fact is pretty important. I am skeptical that only counting drips will ever be that accurate (at least with low cost equipment). Drip sizes vary some. It is pretty hard to get around that. Now if you don't care about print accuracy this can be fine. For example you could print some object that is real detailed but is ten percent too tall and it may still look great. However for other applications very high accuracy is needed. Gears would be a very clear example of that.
I submitted a video in a different thread using a caliper I took apart to measure the water level with up to 0.02mm accuracy: http://3dprintboard.com/showthread.p...on-idea/page11 Check out the improved video, the first is really bad!
It is quite cheap. Unfortunately the video may not do much to calm your worries that it will take up space, since I used a huge sheet of styrofoam. However I assure you this is not at all necessary. With a properly designed float it can have almost no effect on the maximum size of the print. Additionally, a slightly bigger container for the printer could always be used! Also it will not cause an ripples. The float steadily rises with the liquid if built properly (which laser cut parts would be). As I stated on that thread this with a Kalman filter will allow for very very high accuracy and resolution in the Z-axis. The USB can be used to receive the data here too! haha