Laser Underwater Beacon

Introduction: Laser Underwater Beacon

About: DIY for underwater.

Do you have to dive ever? Imagine how it can be difficult to navigate under water, come together in the right place, mark an exit point or an interesting place down there. Even during the day and in good visibility is sometimes difficult to find necessary place in the underwater world.

Step 1: We Used:

Step 2:

In the lower part of the case there is a round battery holder with three 18650. A reed switch is glued to the holder body. To rotate the laser beam we used a motor with a reducer. Our motor is rated at 12 volts but it works fine at 3.7 volts. The laser module is installed in the top cover. The cover is made of aluminum and this provides excellent cooling of the laser. A laser beam drops on a rotating lens and a mirror. The lens converts the laser point into a line with an angle of 30 degrees. The rotating mirror causes the laser line to rotate.

Laser beacon switches by rotating a black Velcro ring with a magnet. Because of good cooling laser can work unlimited time without overheating and thanks to 18650 3400 mAh batteries the run time is 20 hours!

Contacts for charging the batteries are pushed through the bottom cover so the laser beacon can be recharged without opening the case.

Seen under water at a great distance up to 70 meters and is very effective attracts attention of divers. We did it just for fun but it proved to be very useful to mark an important place, exit point, etc.

We used a very powerful laser, but since it's not a dot but a line, it does not blind the eyes.
We tried lenses with different angles and chose 30 degrees so that the light spread as far as possible. The green light is better than the other spreads in fresh and salt water.



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    7 Discussions

    Very interesting project, could you add more info about build process? There's no data about o'rings used.


    1 reply

    We used an aluminum pipe with an outer diameter of 50 mm and a transparent acrylic tube with an internal diameter of 56 mm. Between them are installed 4 orings 5 mm thick and inner diameter 48 mm.

    Nice. Does the unit sink and is it self righting so you get a vertical line to help with getting your orientation in the dark? Does the laser light attract or repel fish?

    2 replies

    The unit has a negative buoyancy and is always strictly vertical. We can drop it on the rope from the side of the boat so that divers know where to return. If we dive to a wrack ship along a rope (as often happens on the Red Sea) then the beacon is hung down the rope so that you can quickly find where to return.

    At the ends of the beacon there are fixing hooks to which we often attach a small buoy and lead weight. In this case is convenient to take beacon with you and drop it somewhere if necessary to designate any desired place on the bottom.

    We often use DIY laser pointers for diving. As a rule, both in the river and in the sea the fish does not react to the laser, in most cases it does not react. But sometimes, rarely enough, fish are played with a laser like cats.

    that's pretty sick!
    200mw is dangerous for the eye?

    1 reply

    Yes, as a dot it's very danger but as a line + underwater + rotating = no.

    At a big distance it looks like a very short flash light.