Wednesday, December 7, 2016

Starry Sky Troubleshooting

Starry Sky is a holiday light projector which projects patterns of red and green laser wherever you point it... assuming it works.

Projection similar to the one the Starry Sky product creates.

I purchased one of these through Amazon, and it didn't take long at all to see why this particular product is no longer available. Just one night after setting it up in my front yard, the green light disappeared, leaving just the red. Picking it up and shaking gently yielded a disconcerting rattling inside. 
I carefully disassembled it and took stock of the design (no photos, so I'll try to describe as best I can). Inside is a DC motor, with a gear that's linked to two other gears on spindles linked to each laser. The spindles each have a tiny, square plastic filter which splits the laser beam into various patterns as the gears rotate. 

Beneath each spindle, the lasers are each enclosed in a cylindrical aluminum heat sink to dissipate heat, and the heat sinks mate with the spindles and, in turn, the gears, with a threaded connection. The problem I encountered is that in operation, the green laser decided to unscrew and fall away from its mounting.

The solution was pretty easy, apply some Loctite thread locker to the threads and screw the green laser's heat sink back into its spindle. After this the device seemed to work normally.

In case you don't care for the ever-changing patterns of red and green, there's a simple fix. First off, the wiring to power the DC motor runs to a small molex type connector (pictured below); simply disconnect the motor so it no longer receives power.

Then, undo the screw holding the motor's gear in place and carefully lift the gear away; now note the lasers' spindles spin freely. Next, connect the plug to a convenient electrical outlet and of course keeping the lasers safely away from your eyes, rotate the red and green gears to alter the scatter pattern of each laser until there's a satisfactory balance of red and green. Once that's the case, replace the motor's gear and screw it back on so it stays fixed.

It may take some trial and error to ensure a satisfactory brightness and pattern are emitted, so don't firmly tighten all the screws right away; just tighten one so things are reasonably in place, then test it wherever you plan to place the projector.

Review products carefully and pick one that does what you want it to do but isn't rife with poor quality control as demonstrated here.

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