For a professional project, I have to find a distance sensor which can measure distances from 50 mm to 250 mm minimum with a resolution below 1mm like 0.5mm.
I've been looking everywhere and the resolution is never below 1mm for low quality sensors that are often used in arduino projects.
The only ones I found are from OMRON like E3Z LS83-2M which seems to have a great resolution but I can't find a value. The thing is that even if it is called distance sensor, I have doubts for it to just be a proximity sensor.
So do you guys have a reference of a sensor below 200$ that can do it or can you validate my choice of the OMRON sensor pls?
Thank you for your answer!
The sensor looks perfect but the price can't be found without asking a quotation.
I'll do so but the sensor may be really expensive.
I asked my manager to determine the maximum price that we can spend.
I found a lot at 10-40$ with 1mm resolution but almost impossible to find below so it seems that we will have to pay the price...
I'm still hoping to find a 200$ with 0.5mm resolution.
Try one, and average some number of readings to see if that improves precision. Let us know what you find.
A very rough rule of thumb with sensors is that for each guaranteed factor of 10 improvement in precision, the price goes up by a factor of more than 10.
After some tinkering, this fellow found that "Using phase, the HC-SR04 can reliably resolve distance changes less than 1 mm." (You won't get that with an out-of-the-box HC-SR04: you have to modify it like he did.)
Even if his findings are true, I'm NOT saying that incredibly cheap sensor is for you. And there are many selection criteria you haven't mentioned.
But I'd be surprised if you can't find a commercial/industrial sensor that can do what you need. For example, these guys have ultrasonic sensors that appear to be in your ballpark, cost-wise and "accuracy"-wise:
BTW, I have found that calling vendors on the PHONE and TALKING to a Real Live Person is often the best way to find what I'm looking for. Even if they don't have what I need, they may know a company that does, or can suggest an alternative approach. (And phone calls usually work much better for this than email.)
The key here is that distance changes are being measured, not absolute distance.
As the article points out, measurements of phase changes are limited to one wavelength (8 mm at 40 kHz) total, or about 4 mm of there and back travel. To get absolute distances to that accuracy, you have to accurately count the number of carrier crests to the reflecting object, plus the fraction, which seems difficult to impossible with the HC-SR04. Nice work, though!
Yes, it is nice work, and the article does include a formula for absolute distance which includes time and phase, and is said to be accurate to about 1 mm. Not exactly what the OP needs, but if the OP has more time than money or good sense, it may be fun to try.
You would think that a time-of-flight optical rangefinger thing would exist (ultrasonic is not the most accurate and have a spread), and it should not be terribly expensive, especially if he is willing to put a small reflective surface on the other end.
It's like an industrialized, short-ranged and accurized version of the hand-held measurement thingy that contractors use to take measurements of your house.
For $30 you can measure up to 20 meters with accuracy of within 2mm, along with a screen, battery, software and everything.
I'm amazed you have had so many useful suggestions on such little information. You havent told us ANYTHING about what you are trying to measure the distance TO.
Is it a flat surface? Is it reflective? Is it conductive? Hard or soft? Solid or liquid? Is it moving? What are its dimensions - is it like a wall, a wire, or a bullet?
For this project, I need to measure the 4 corners of a solar panel while being docked into it's storage structure. The goal is to tilt the solar panel if it's not totally vertical to avoid damages.
Unfortunately, it is a proximity sensor and I need to measure distances!
And the second sensor has a range from 20 cm to 5m so it won't work
This might be a solution if I don't find a better sensor thanks!
This sensors seem to fit with the requirements but they are about 400-500$ so it might not be validated by my manager. I will contact them to ask some questions about the compatibility with an Arduino or another cards!
It's not that simple ^^
The system will be used in a clean room with large satellite wings so we can't measure the level by using a contact sensor put on it ! It has to be contactless.
Probably best if you draw a diagram of what you want to achieve. I suspect there are better solutions than trying to get accuracy above spec on sensors. Eg a laser and sensor positioned appropriately will detect pinpoint accuracy of alignment.
