Photocell reflector + Arduino

Hi all,

I'm interested in connecting arduino board with a photocell reflector, something like this ( I know that exist other options like ultrasonic sensor, but the problem with this sensor is the angle (15°), because I need a directive line of vision around 2 or 3 meters. That's why I'm thinking of photocell reflectors.

I found this option (, but if I would like to detect objects in more distance than 1 meter, then I need the photocell.

The main question is how to connect arduino with the photocell reflector, because I am not sure if this is possible.

Thanks a lot guys! :slight_smile:

So you are looking for a light beam detector. The easiest way is to use a laser (readily available on eBay but you need to be careful to find one designed for continuous operation, which means it needs a proper heatsink) and a photocell mounted at the end of a piece of black tubing. For retroreflectors you can use those designed for marking street-side objects.

A LDR can simply be connected between an Arduino input and ground with INPUT_PULLUP mode enabled.

Thank you very much for the reply.

The problem of using lasers is that maybe are dangerous for the eyes (especially if there are childrens), that's why I'm looking for an infrared sensor like a photocells reflector.

But, I cannot find any infrared sensor that can be connected to arduino board and it creates a line vision around 2 or 3 meters (like a laser).

I know that is difficult to find a solution for this problem. The idea is:

Can we do a barrier sensor like there are in parkings with photocells or something using arduino?

Because the ultrasonic sensor is not working properly in this scenario (angle 15 degree more or less) and the lasers are maybe dangerous for the eyes... so I think the solution is an infrared sensor.

What do you think?


Can use a commercial PIR, they have relay closure output that arduino can read.

Thanks so much! That's exactly what I was looking for.

So, can I connect this sensor directly in the digital output on the arduino board?

Excuse me for the question (I'm newbie), but, what does it mean relay closure output? Is that the sensor returns true or false if there is an object or not in the zone detection?

In this case, I only need to do a simply program that it counts when the variable is not zero and it does nothing when is zero (idle state)

Thanks! ^^