Optics: need for a laser sensor... "array" ?

[maestun]

Hi to all,
A friend of mine has one of these devices:


This device has a sensor band (the blue vertical band on the right side) which is able to detect a laser beam in full daylight, even from a big distance (> 100 meters). This used to know if you are aligned with the laser beam, or if the device vertical position is too high / too low.

The laser emitter has to be of the same brand, so I guess it is emitted with a series of pulses of given frequency, which is recognized by the receiver.

The problem: I want to build the same kind of device (with some addons). For this I must know what the laser detection part is, which technology is used, and if I can source the same kind of part and where... And I have no idea where to start !

Could someone explain to me what is the sensor technology used here, and how the laser beam is "separated" from the daylight for the detection ?
Thanks

[rstofer]

Borrow the unit and take it apart!

The beam is probably modulated to make detection easier.  IR remote controls are modulated for the same reason.

[maestun]

Yes, I thought about that (although that might not give me much more info about the sensor), but my friend lives far away and needs his device for his daily job

[Rerouter]

I would imagine a proper sensor at the dead center, the black material spreads the beam wider, and allows them to use cheaper sensors for the rest of the range,

From personal experience i know those things are pretty hard to get tracking unless you overlap the center point while moving about, (for say 25m distance)

[jeremy]

Laser detector arrays == CCD == "digital cameras". I have seen them used many times for laser beam profiling. But I doubt this uses a CCD (or CMOS) detector, it probably just uses two photodiodes. When the signal reaching both is equal you are aligned. When the lower one has more, move up. Etc etc

[maestun]

Hi to all, and thanks for the answers.
I don't think the sensor is made of photodiodes, it seems made from "solar-panel-looalike" stuff. Also, how could be the daylight filtering made ?