user76957: I want to try measuring the orientation of an object by measuring the distance between a "flat" surface to the surface of the rotated object. The problem I assume is that if the surface being measured is at an angle to the distance sensors, the beamed lights from laser or infrared proximity sensors, for example, would be reflected at an angle and not return to the sensors at all.

Would this actually happen, or am I misunderstanding some properties of these sensors? Which sensors would work in this kind of application, and which sensors would not work for sure (I read from another post that ultrasonic sensors would definitely not work in this case)?
(Added a crude sketch of the problem I think is going to happen)

user76969: Using ultrasonic sensors would be a very sensible solution in your use case.
I am currently working on a similar project with a company in Denmark, where the objective is to detect cars on parking spaces. For this task, I used two of these ultrasonic sensors from DFRobot for the prototype:
https://www.dfrobot.com/product-1935.html
They were very easy and simple to setup on an Arduino UNO and worked perfectly fine even when two were sensing at once.
Though I have to mention, that they need a serial connection each, but this can be worked around using a multiplexer or a developer board with more serial connections.
I also found that the ultrasonic sensors work better than time of flight sensors in outdoor conditions. They are very robust and wont be as affected by dirt for instance.
A little speck on the lens of a ToF sensor and it will be rendered useless.
Ultrasonic sensors are also widely used in the car industry for parking aid solutions where they have to detect lots of different surfaces and be very precise in doing so.
Ultrasonic sensors are great. And yes, they can interfere with each other, but as long as you dont put them on top of one another, it should not be an issue.
You should be able to detect the distance to a trailer in two different places using ultrasonic sensors as long as the trailer is within the sensors range.

76957: <p>I want to try measuring the orientation of an object by measuring the distance between a &quot;flat&quot; surface to the surface of the rotated object. The problem I assume is that if the surface being measured is at an angle to the distance sensors, the beamed lights from laser or infrared proximity sensors, for example, would be reflected at an angle and not return to the sensors at all.
<a href="https://i.stack.imgur.com/1KoTZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1KoTZ.png" alt="enter image description here" /></a>
Would this actually happen, or am I misunderstanding some properties of these sensors? Which sensors would work in this kind of application, and which sensors would not work for sure (I read from another post that ultrasonic sensors would definitely not work in this case)?</p>
<p>(Added a crude sketch of the problem I think is going to happen)</p>
 76969: <p>Using ultrasonic sensors would be a very sensible solution in your use case.</p>
<p>I am currently working on a similar project with a company in Denmark, where the objective is to detect cars on parking spaces. For this task, I used two of these ultrasonic sensors from DFRobot for the prototype:</p>
<p><a href="https://www.dfrobot.com/product-1935.html" rel="nofollow noreferrer">https://www.dfrobot.com/product-1935.html</a></p>
<p>They were very easy and simple to setup on an Arduino UNO and worked perfectly fine even when two were sensing at once.
Though I have to mention, that they need a serial connection each, but this can be worked around using a multiplexer or a developer board with more serial connections.</p>
<p>I also found that the ultrasonic sensors work better than time of flight sensors in outdoor conditions. They are very robust and wont be as affected by dirt for instance.
A little speck on the lens of a ToF sensor and it will be rendered useless.</p>
<p>Ultrasonic sensors are also widely used in the car industry for parking aid solutions where they have to detect lots of different surfaces and be very precise in doing so.</p>
<p>Ultrasonic sensors are great. And yes, they can interfere with each other, but as long as you dont put them on top of one another, it should not be an issue.</p>
<p>You should be able to detect the distance to a trailer in two different places using ultrasonic sensors as long as the trailer is within the sensors range.</p>
