Moving head lighting fixture control by the use of PIR sensors (DMX Pan/Tilt)

Projects General Guidance
1

Hey everyone,

The idea for my project is to create an algorithm that will take information from 4 PIR sensors placed in every corner of a rectangular area. This data will be converted into coordinates by the use of an algorithm (any ideas?). The idea is to then use a DMX shield for the Arduino to connect it to a moving head light fixture , and translate the coordinates somehow into DMX language, controlling the pan and tilt of the moving head. This way a the light will follow the person.

my questions are:

  • what kind of PIR sensors would you recommend? From my understanding, the measuring angle has to be at least 90 degrees and they have to be able to detect a person up to 4 or 5 metres.
    -How would you assign the pan/tilt to the output of the sensors? Imagine the area that is made by the sensors to be a 2 dimensional rectangle on the x and y axises of the Cartesian plane, would it be possible to assign the pan to the x axis and the tilt to the y axis?

I am sorry if I am being unclear, I am doing my best.
Any help would be much appreciated!

Tom

2

A PIR is 2-state device... Either it detects movement or not.

The best you can do is point toward the corner where movement is picked-up or half-way between two sensors if movement is picked-up by two sensors, etc.

3

@DVDdoug

In that case, a PIR sensor is either detecting movement or not, it does not print any serial data like ultrasonic sensors? (0-1000?) Would you use ultrasonic sensors instead?

4

Since you brought it up - personally, I like using the ultra-sonic sensor for tracking. I used one mounted to a stepper motor to track me; setting the operational distance made it nice. All works well unless the moving object and a stationary object (wall) are too close to each other; hence, the perimeter scan will need to have a shortened distance. Once it locks to the target, perform small angle adjustments, left and right, to maintain the strongest reflection and track the best reflection. Once the moving object is outside of the predetermined settings, begin a continuous 360 or 180 scan- depending on your needs.