Z axis calibration idea

[Aztecphoenix]

this got me thinking, if we can get real time feedback for the Z axis, what if we used a laser rangefinder type system to identify how far the print head is from the base of your build area and then by adding small photosensors, one at each corner and one in the middle of your build area, in theory wouldn't we be able to make the Peachy "self calibrating"?

so, the laser would shine and the range finder would count how long the light takes to reach it, then the laser would scan to find the center photosensor establishing that as zero, it would then move to each corner measuring it's travel distance on the X and Y, after locating the corner it would return to center and repeat for the other three corners, it could then take those measurements to determine the X and Y build area and by having the real time Z axis feedback calculating the entire build volume would no longer be required and the machine would be able to calibrate itself prior to each build.

the main reason I am looking into this is I plan to use different sized build resivoirs for different prints ( no need to use a three cubic foot resivoir for a print that only takes up five cubic inches)

[harpo99999]

unfortunatley the speed of light vs speed of electricity in wires is light is several times faster, partly due to the resistance of the wire, so using the laser to calibrate the distance would not be effective or reliable

[Aztecphoenix]

unfortunatley the speed of light vs speed of electricity in wires is light is several times faster, partly due to the resistance of the wire, so using the laser to calibrate the distance would not be effective or reliable

some kind of range finder be it laser or sonic, I'm more curious about the feasibility of the overall concept

[Anuvin]

Well sure it's possible to use a laser rangefinder. The code's in python, open and easy to learn and change. Problem is that I don't think you can get either method of detection and still get a printer out for under $100.

[Aztecphoenix]

Well sure it's possible to use a laser rangefinder. The code's in python, open and easy to learn and change. Problem is that I don't think you can get either method of detection and still get a printer out for under $100.

I'm just talking about after market mods, if they want they can add it to the pro version for a slightly higher pricetag (you pay more for the pro as it is)

[mike_biddell]

Refining the optical mouse idea, it is much simpler to use a strip of textured plastic about 1/2 inches wide, 1/10 inch thick and an appropriate length. Attach this to a small polystyrene float. Mount the mouse circuitry in a static position at the top of the tank, so that the float strip moves paste the mouse window (feed the strip thru a slot by the mouse read window), as the depth in the tank increases. This would definitely work and give excellent Z resolution at a very cheap price.

[Aztecphoenix]

Refining the optical mouse idea, it is much simpler to use a strip of textured plastic about 1/2 inches wide, 1/10 inch thick and an appropriate length. Attach this to a small polystyrene float. Mount the mouse circuitry in a static position at the top of the tank, so that the float strip moves paste the mouse window (feed the strip thru a slot by the mouse read window), as the depth in the tank increases. This would definitely work and give excellent Z resolution at a very cheap price.

the only downside is you have to have as much clear space above your build reservoir as the actual depth of the reservoir so the gauge can have full travel.

[mike_biddell]

not necessarily..... u cud have the upper tank offset by 1 inch or so and have a scale slot on the side of that too !!!!

[Aztecphoenix]

on further reflection, a separate tank off to the side of the whole machine attached with an umbilical to the build tank, that way the water would displace both at an equal rate, it just might work.

this setup could also be used as an overflow cut off switch, the gauge has a contact on top and an adjustable slide with the second contact, this way as the gauge floats up when the top reaches the slide it can activate a solenoid valve to stop the drip flow.

[Anuvin]

This thread is super awesome. I hope someone tries this and reports back!