Locate Object in Space

Hey guys,
I’m working on a new project and would like to get some help before I begin.

I want to locate and object in space, relative to a fixed position. The object itself should be inside a sphere in space with a fixed radius (let’s say 30-40 cm radius) and should be within a 5-10 cm accuracy. (see the picture). For the example’s sake, let’s say that if the object is in the sphere, a green light will turn on. Otherwise, a red light will turn on.

I’m wondering what equipment I should get, how to approach it in the first place and how I should take the fixed sensor in account.


Please display your image(s) in your post so we can see it(them) without downloading it(them). See this Simple Image Guide

Do you mean that the object can move around inside the sphere and you just want to know whereabouts within the sphere it is located?

Is so some ultrasound sensors may be appropriate.

On the other hand if you want to locate the position of the sphere within a large space it will be difficult, expensive or impossible. You have not provided enough information.


Hey Robin,
Thanks for the reply and sorry for the image. I've uploaded again, hope its ok this time.

I want to place a sticker, sensor, etc on an object and check its location in reference of another fixed sensor. After I know the object's location, I want to define an imaginary sphere, which is located at a set distance from the fixed sensor. Every time the object enters the imaginary sphere, I want a green light bulb to light.

I hope this is clear enough, please look at the image, I think it's pretty clear.


You are not going to be able to triangulate the position of an object in 3D space with one sensor.

If the object is distinctive then maybe its position could be determined using cameras.
The Arduino is not particularly suited to image processing.

Pozyx will work.

Is it possible to place a light (LED, perhaps) on the disc and then arrange a directional optical detector (a photo-diode at the bottom of a tube?) which could be traversed to identify the angle at which it sees the light. A bit like taking a bearing from a lighthouse at sea.

I believe Posyx is expensive.


jremington: Pozyx will work.

"How many modules do I need for localization? For 3D localization you need at least 5 modules. One module for which you want to know the position and 4 modules that act as anchors."

idolavi16: should be within a 5-10 cm accuracy.

From the chart it looks like Pozyx will give you better than 25cm accuracy 100% of the time, 10cm accuracy about 75% of the time and 5cm accuracy about 30% of the time.