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Lasers from Scrounged Star Shower

Lasers

We bought 3 Star Shower Christmas lights to use around the home. These devices cast a grid of sparkly "stars" and look awesome on trees as the tree moves in the wind.  The "stars" are creating using a red and green lasers passed through a diffraction film.

Only one survived the rain.  The other two found there way to my bench for laser extraction.  I found several items to use in future projects.

Power Supply

First the power supply is a 5VDC wall wart. Both failed. One is outputting about 7VDC unloaded, probably why that unit failed.  The other is just dead. I tore into the totally dead supply and found a lot more parts then I expected. I did save a couple of electronic parts but I don’t recommend you bother.  Check the supply to see if it’s working. If not, cut the cord and keep it.   The connector is a great thing to have in your parts collection.

Main Unit – lasers

You have to get into the package but there are four rubber grommets covering Phillips screws. Careful not to press the grommets into the case!  The screws are all the way down inside. You will need a long #2 screw driver to reach them.  I just used a big screw driver and tore though the plastic. Was a huge mess and dangerous.  For the second one, I will find a screwdriver that works.

Inside, mounted to rear cover is a small PCB, again with many more parts then I expected. I saved none of those, just pull or cut all those connections. It’s surprising that each of the internal parts are connected to the PCB with connectors. They must have needed these due to the way the device is assembled.  Just not used to seeing connectors inside this kind of low cost device.

Once the rear is open, remove the screws that hold on the front cover, all the way down inside the unit.  The front cover slips off to reveal more screws.  Take those out to release a large heat-sink with lasers..  This block has a 4-Ohm heating resistor and a thermisistor as well as two laser modules. Once you have the heat-sink out, remove the two small screws holding the lasers and push them out of the block with a screwdriver.

There is also a CCDS light sensor on the cover worth saving. I also kept the thumb screw and matching nut from the mounting stake.

Testing the Lasers

Both worked fine although the Red laser is wired backwards from expected.  Both lasers have a red and black wire. In the electronics world (not the electricians world!) black is commonly used for ground or negative. This was true for the green laser but not the red. I pulled the red laser out of the trash to double check it, sure enough, red was negative.

The green laser powers up at a bit more then 2V and is super bright at 2.4. The current draw was around 250mA.

The red laser powers up at about 2.5V and pulls about 125mA.  I’d guess they both are meant to operate at 2.5V but I could be wrong.  While the current goes up sharply on the green laser after about 2.3 volts, I don’t notice the brightness being a lot more above that.

So the tally is.

  • Bright Green Laser
  • Bright Red Laser
  • CCDS light sensor with lead wires
  • Waterproof power connector (nice)
  • Thumb screw and nut, useful in an upcoming 3D printed project.

Summary

I am surprised at the amount of electronic components inside both the device and it’s power supply.  I believe the first unit, the one I scrounged, failed due to the power supply even though there was drops of water inside the device.

One idea I have is to use these parts to make my own "star" projector. 3D print an enclosure etc..  Maybe have the lights trigger on motion or sound, pointing into the woods behind my house…  Any other ideas?

I could capture some pictures of the guts next time if there is interest. Let me know in the comments.

Posted in Discovering, Hacks, Parts, Projects, Scrounging, Scrounging Parts.

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4 Responses

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  1. uCHobby says

    @h Yea, stupid question.. I’ll take pictures of the second one when I tear it down

  2. uCHobby says

    @Jose Yes, normally you would expect a supply to output high when unloaded but this is a regulated 5VDC supply. Lots of parts inside. I’ll try loading it but given that the device has failed I expect the supply has as well.

  3. h says

    You really have to ask if we want pictures of the guts? 🙂 Want pics of the lasers in the trees too, though I’m guessing they might have to be long exposures…

  4. José Xavier says

    There are a lot power supplies that output more than 5v unloaded. Try to connect a led and see if it output 5v.