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1 mm accuracy IC sensor

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SiliconWizard:

--- Quote from: Marco on February 20, 2020, 01:11:07 pm ---Without going to MHz range it's hard to keep a tight beam with ultrasonics. Also you'll need temperature compensation.

--- End quote ---

Agreed. And even so... keeping 1mm accuracy over 100mm with ultrasonics will not be that easy, and will never fit within the volume the OP was aiming for.


--- Quote from: Marco on February 20, 2020, 01:11:07 pm ---Though the ST solutions hardly seems temperature insensitive either.

--- End quote ---

The ST proximity sensors will not give you nearly the accuracy the OP is looking for. They are typically used as proximity sensors for mobile phones/tablets just to estimate how close you are to them... Just take a look at the graphs in the datasheets. You won't get any better than +/-5mm or worse even on the shortest range model. You may be able to partially overcome this with frequent calibration, but I wouldn't count on that. Or that may make the solution very cumbersome to use in the field.

Knowing more about the application may help think of an alternative. What is the typical environment? Is the distance going to be always measured in open air? What material is going to be the object to measure the distance from? What's the typical operating temperature range?

If the object is conductive, one possible approach could be to combine an inductive or capacitive proximity sensor (for the short distances, such as < 20mm) and ultrasonic or ToF sensor for the rest of the range. The 1mm accuracy over the full range would still be hard to get, and the overall size... much larger than expected.

AndyC_772:
What is it that you're trying to detect, and what's the end application?

Klemken:
Basically i will measure distance from sensor to a wall covered by different color and materials of fabric. That is why i am sticking with ToF technology. There will be several sensors at 1cm space beetwen each to wor kas a simplified lidar system. They will be all mounted on a rotating pcb, that will rotate with 20RPM (smooth bldc motor rotating in, no jerky step motor).

SiliconWizard:
Ouch, so to make things even easier, the sensors are going to move! :-BROKE

Why do you need it to work at such a short min distance (1mm)? That would mean that your sensors are rotating at 1mm from the wall, sounds pretty risky on top of that, unless I missed something.

Gyro:

--- Quote from: Klemken on February 20, 2020, 02:45:20 pm ---Basically i will measure distance from sensor to a wall covered by different color and materials of fabric. That is why i am sticking with ToF technology. There will be several sensors at 1cm space beetwen each to wor kas a simplified lidar system. They will be all mounted on a rotating pcb, that will rotate with 20RPM (smooth bldc motor rotating in, no jerky step motor).

--- End quote ---

It's important to put major requirements like that in your OP, so you don't waste peoples' time.

If you want ToF then Ultrasonic will have more resolution (not accuracy) at very short distances but the sensors will be bigger than your footprint and spacing requirement (fabric might be an issue too).

Maybe you can do something with small reflective opto detectors rather than ToF, but again varying surface reflectivity is an issue. 1cm spacing sounds unachievable when you take into account motors and slip rings/couplers though. [EDIT: Ah you maybe mean 1cm vertically stacked on a a single PCB] I can't see a Laser ToF system being that compact either.

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