# Measure height of rotating laser

Hi,

I’m a new member and neither a native English speaker, nor an arduino native.

I want to measure the height (position) of an rotating laser beam. The beam will
rotate in a horizontal level and will touch the sensor several times per second.
The laser will be emitted by an device like “Bosch Professional GRL 400 H”.

The Arduino should process the data from the sensor and do position-corrections
by a linear actor depending on the measured position.

Do you have experience? I need advice in choosing an appropriate sensor.
Maybe CCD or CIS. The resolution must not be fine. An accuracy of 0.5mm is enough.
But the measuring range should be between 10cm and 15cm.

Would be fine, if only red or green laser output is considered and not normal daylight.
Maybe this could be achieve by a filter in front of the sensor.

What sensor do you suggest?

Best regards,

alex

But the measuring range should be between 10cm and 15cm.

What does this mean? Please post a scale drawing of the entire setup. Image posting guide

OPs image:

Seems easier to mount a laser range finder pointing at the floor right to the unit. Add a correction value to compensate for mounting position and read the height directly.

@jremington: the floor where the vehicle with the sensor moves is not horizontal. But i want to assume, that the difference between the highest and the lowest point will be less than 10cm, maybe 15cm.
So 10cm scale will be good. 15cm will be better. This means, that the length of the sensor has to be between 10cm an 15cm.

@dougp: the floor is not horizontal, therefore it does not make sense to measure the height from the floor.

The sensor could be something like this:
https://www.eureca.de/datasheets/01.xx.xxxx/01.04.xxxx/01.04.0074/TCD1710DG_e.pdf
but this one is too short.

Measurements like "height" require a reference. Do you mean "height above sea level"?

If the sensor is being struck by the laser then I would say the sensor's height is zero, compared to the laser.

Why don't you measure the laser's height at the laser tripod? Run a measuring tape down one leg or all three. Write that number down and move on to the next project.

Hello MorganS,

i think it is a translation problem. Sorry.
The reference is always the horizontal "layer", that the rotating laser draws in the room.

The position of the laser keeps fixed. The laser-layer is always horizontal.

Now i want to figure out with a portable device including the sensor, how the distance between ground
and the laser-layer changes depending on the position of the device. Because the floor is not horizontal.
It has little hills and valleys.

Where is the highest point in the room, where is the lowest? What is the difference?

I only need a suitable sensor.

Commercial laser-grading systems keep the sensor centered on the horizontal beam. They don't need to measure anything other than "too high"/"too low"/"just perfect". The sensor moves up and down relative to the vehicle to stay on the beam.

So now your problem is moving the sensor up and down. 10-15cm is kind of small. Maybe you can find a small linear actuator that will fit. See Firgelli Automation or their related company Acutonix, which does smaller actuators.

Then the problem is measuring the distance between the sensor and the floor. The actuator might have feedback or you could use a Sharp optical distance sensor.

Another out-of-the-box solution might be to use a Pixy camera and have it just watch the red dot on a wooden stick.