Long-distance proximity sensor
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@fcwilt Sounds complicated
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@oliof I don't know if the piezo sensor would work with an ABS sheet laminated to an MDF Board they are very heavy.
I don't want to spend this much on an Ultrasonic sensor It will be better to go with a laser one. -
@t3p3tony Yes, I think a laser sensor would be the best choice, and Yes 0.3mm is nothing, I'm using a 5mm nozzle and 4 mm layer height.
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Thank you everyone I really appreciate your help.
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@afllak said in Long-distance proximity sensor:
@t3p3tony Yes, I think a laser sensor would be the best choice, and Yes 0.3mm is nothing, I'm using a 5mm nozzle and 4 mm layer height.
Well glad to hear you may have found a solution.
Frederick
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@fcwilt Thanks, appreciate your help.
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@afllak Take a look at laser interferometers. The commercial/industrial units are expensive, but it might be an opportunity to figure out how to make it cheaply. The resolution is very high- like 5 nm, which you don't need, so cheaper optics might give the needed performance without the high cost.
Example: https://www.keysight.com/us/en/assets/7018-06711/technical-overviews/5964-6190.pdf
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We experimented with a sensor based on two Adafruit TOF (time of flight) laser chips two years ago. Specifically, they were the VL6180X chip.
The lasers were mounted angled on a smooth and level surface parallel to the bed and the average of the two measurements obtained was calculated with and Arduino.
We achieved very good repeatability, but from a distance that was too close for what we needed. Corrections or changes of focus would have to be made in how to apply triangulation, optical elements or other methods, but it was a promising attempt.Perhaps someone will dare to develop it to apply into a reliable "solid state" autolevel, which has a greater distance than current systems.
Currently we make a long probe with a flag with an optoendstop that measures the activation point, and a solenoid to deploy and pick up the probe. But this system is "only" reliable up to 20-25mm of free probe travel.
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I used this for a project a few years ago. Might be worth looking at given the accuracy required and that you could get an initial reading before your first move to inform how you approach the bed for your final measurement.
https://hackaday.com/2014/03/29/hacking-a-laser-tape-measure-in-3-easy-steps/
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@marcossf said in Long-distance proximity sensor:
We experimented with a sensor based on two Adafruit TOF (time of flight) laser chips two years ago. Specifically, they were the VL6180X chip.
I looked at that yesterday. Unfortunately the datasheet indicates there are large variations of the reported range with temperature and supply voltage, up to 5mm AFAIR.
There are better device available but they are not cheap, e.g. https://www.micro-epsilon-shop.com/de/ild1220-25-miniatur-laser-wegsensor/4120261/.
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@dc42 These Epsilon lasers was our inspiration for trying to do some similar but masivelly cheaper. They are very good but outrageously expensive, typical gadget that would be good for hacking.
We tried with two VL6180 chips in oposed angles and know distances to triangular the measures and divide accuracy. Temperature was not the main concern, so we tried to fire from 10cm away the hotend. The best resolution we get was near a milimeter, too much for autolevel or accurate z-offset findings.
At that time we was even talking about this project with researchers from the laser applications laboratory of the UDC University, as they are clients and friends, and they found it interesting and in a way, doable. But we ended up leaving it to focus on more "prosaic" things.
I still keep some on my desk.
