High precision (~0.1mm) short distance (1 - 15cm) sensor

Hi all, as stated in the title I'm struggling to find some high precision (~0.1mm) short distance (1 - 15cm) sensors. Not sure if I'm searching wrong or such things are not really common. The only one I found so far is this:

but I'm either blind or they don't share what's the accuracy of this thing and I don't understand how can you not include that info for a distance sensor??

Any other recommendations? To give you a bit more context, I am working on a hobby project and I want to measure the distance of a car from the ground to the bumper so ideally, the sensor should be fine for outdoor use (but I can build a case for it as well so not that hard requirement) and ideally it should be fine to measure the distance constantly on a moving car. Also are how would optical sensor (IR like the one above) behave on a wet day? Meaning measuring the distance from a bumper to a wet road? Would it still work, not at all or would give false readings?

As you already mentioned there are several parameters that affect accuracy, repeatability etc. Most prominent is temperature, in detail in your environment.

The output is a voltage, i.e. you can detect small deviations quite well but not necessarily in absolute units. It's also up to you to find an ADC of the required resolution and accuracy.

If you search for automotive sensors and compare prices then you may know why such cheap sensors don't come with sensitive data.

Do you mean resolution of 0.1mm, or accuracy, two different things?

Any major reason for 0.1mm resolution?
You also need to realize that if the surface you are measuring to is moving not just towards and away from the sensor, but across its field, you could have an effect on your reading.
It uses triangulation, so if the surface is not smooth, then irregularites may cause beam deflection issues.

You may have to bite the bullet and buy one and get down and dirty and do some real world experimenting.
You may have to develop an algorithm in your measurement code to cater for real world effects.

If you read the spec sheet, these devices are used for object avoidance in cleaning equipment, not precision measurement down to 0.1mm.

Tom... :smiley: :+1: :coffee: :australia:

Well, a resolution actually. What I really care about is to know if a car is 5 or 6cm from the ground. 1cm accuracy wouldn't really cover that because I could sometimes see 5cm where it's actually 4cm or 6cm, right? So I don't really need to know that it's exactly 4.3cm or 4.2cm, I just want to be 100% sure that 5cm is actually 5cm and not 5cm +/- 1cm.

I want to play with some pot hole detection systems. So again, 1cm accuracy wouldn't really tell me much about small potholes (or other road defects).

Yes, definitely, I am aware of that. In the docs of that sensor, I linked they recommended mounting it perpendicularly to the surface movement for better accuracy if the surface is moving.

Sure, I could, but 1. I hoped to get some idea of the accuracy of that sensor I mentioned (in many other sensors they provide accuracy in the datasheet, so I'm just not sure why this one doesn't show). 2. Can't really do real word testing at normal driving speeds, can I? I'd have to either have a second accurate sensor to compare data or something.

Have a rotating wheel simulate a road surface.



If I was you I would buy one (two incase one fails during testing) and get experimenting, that way you will have some sort of performance base to work your research on.

If you are looking at "pothole" detection, you will need an array across the vehicle front.
Use a calibrated road surface with calibrated potholes, that will be the simplest way to test your application.
What action will take place when you detect a pothole?

At first it sounded like a model car application, now it sounds like a full size car?
Which is it?

Tom... :smiley: :+1: :coffee: :australia:
PS, I would say this item has been made for a specific "cheap" solution to work in a mass produced consumer items.
Would we have "cheap" IMU's and microcontrollers if it wasn't for Xbox, Wii, PS1,2,3,4,5,6 and phones?

Appreciate your ideas but I'm just trying to have fun with electronics that's it. There is no need for complicated experimenting and reinventing the wheel. If what I'm trying to do is not visible/too difficult then I just won't do it. For now, I have two simple questions, one about the accuracy of the sensor I linked and two about suggestions of other sensors which meet my criteria. If I'd be building a million-dollar product for a company then I could go down the road of experimenting and doing my own measurements but it's just my personal project I was thinking about :slight_smile:

I guess same as above. I'm happy doing experiments but I'd rather know the accuracy of the sensor and experiment on my actual solution rather than experimenting to check to figure out the sensor characteristics myself. I just seem to me like it's the same as buying a car a figuring out yourself the max speed because manufacturer doesn't share it.

At first nothing :slight_smile: my goal, for now, is again, just to have fun. If that works out I was thinking of playing with automatic suspension adjustments (soften or poor road, harden on smooth) and maybe also having that as an input for my air suspension. I know that for both of these use cases I could use different sensors (accelerometer for detecting poor road and potentiometer mounted to the control arms for air suspension). But again, I just want to learn more about distance sensors.

Full size car.

P.S. And I didn't say I need a cheap sensor. If there is more expensive accurate, short distance sensor I'm open for suggestions.

It sounds like something Lotus and then other F1 car were doing last century for ground effects and corning stability controlled.

Tom... :smiley: :+1: :coffee: :australia:

Did you try googling with words that reflect your proposed use? Such as...

laser ride height sensor
industrial lidar distance sensor for automotive suspension


One of the first hits sounds very promising...

"The AR500 ride height laser is a compact, metal housed sensor that is capable of measuring up to 1000mm. With sampling speeds up 9,400 Hz, resolution of 0.01% of range, analog or digital output capability, and linearity 0.15% of the range, the AR500 sensor provides a ride height measuring tool elite to other methods."

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