Feasibility of using a distance sensor in a close diagonal

Projects General Guidance
1

Hi. I'm planning something and would like to know from experts if this is even possible.

Imagem to place a Lidar or Ultrasound meter about 5 or 10cm from the floor pointing down. So this sensor would start to open an arc to front giving the the distance from the floor. The initial distance and this distance are two sides of a triagle, so I know the 3rd side (the one parallels to to the floor, that is the distance from the device base to where the sensor is pointing now).
I would need a precision of 1cm tops and a base distance of about 20cm to 100cm.
The material of the surfaces would be mostly wood and cardboard.

My doubts are:

1- One of this sensors would work ok in this diagonal condition? There is a better one?

2- If so, I need the arc to open to front and to 1 side. There is a best fit servo here?

3- I'll use Node.js to code it up and transfer the results over bluetooth or wifi, probably to an Android app. There is a best fit board here?
(Now I'm not sure if a Yum board would suffice, or couple the board with a Rpi, or maybe cable up it to the Smartphone and let the app control the board would be better.)

Thank you.

2

That's a tough one. Think about how the sensor sends out the beam of detection waves. It's going to look a lot like the beam from a torch (flashlight). The beam spreads out as it gets further away from the emitter. As you get to 2m away, the beam is going to mostly cover a circle 50cm across, maybe. So which part of the floor does it "see" as the distance measurement?

A laser based sensor will use a tighter beam, although there is always some spread, even with a laser. Getting a laser to measure those kinds of distances will be expensive.

  1. Yes a servo would probably work.

  2. No, a basic Arduino can do all of this, including bluetooth.

3

You could look into "laser tape measure", example

This would give you the angle (you know from servo panning) & distance (from laser measurement).
Can it interface with Arduino? I don't know, there are likely others out there that can if this one cannot.
I saw a Stanley unit with 0.05" accuracy too.