PIR motion sensors

Hey guys new guy here! I am doing a project where I am making a crawler out of trash and I want to use PIR motion sensors to detect someone within its range and approach them. My teacher told me that a problem I may run into was that the sensors may begin to read objects in the environment and cause the bot to stop. I was wondering if this was the case even though the PIR sensors are going to be these http://www.miniinthebox.com/human-body-infrared-sensor-module_p406976.html#prod_description. Please lend me knowledge! :stuck_out_tongue_closed_eyes:

You'll probably want to put a 'collar' around them to narrow their field of view, perhaps even remove the fresnel lens (which is there because it gives the sensor a wider angle view). The ones you indicated are adjustable sensitivity so you will be able to adjust the detection range somewhat.

What's going to be a problem is they sense motion -- really, an abrupt change in IR radiation. You'll have problems if the people aren't moving, and even if they are, the sensor may not allow you to respond quickly enough or discriminate well enough to find a person to move to.

But being a purely academic exercise, that's probably OK.

It's probably way beyond the scope of your project to rig up a stepper motor to pan the sensor left/right and thus give you more opportunity to see IR sources 'move' (due to the sensor doing the moving) and estimate a target's position from the angle.