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.

Tuesday, December 6, 2016

Sunday, November 27, 2016

Foscam AC Adapter Teardown

I still own a couple of Foscam wireless IP cameras. 

I'm done with that brand in favor of Amcrest (sort of a spinoff of Foscam with far superior design and usability aside from the marginally unusable mobile app), but I believe firmly in using a product up to and beyond its predicted life span if it's able. Up until just weeks ago they were performing satisfactorily, then I stopped receiving motion detection alerts from first one, then the other. Could've been a power surge, though the UPS I have my desktop PC hooked into reported no recent events.

Both had curiously similar symptoms. The older camera, an FI8918W, presented with its ring of infra-red (IR) LEDs all blinking simultaneously, with a red indicator LED in the rear constantly flashing and a faint clicking in time with them. The newer one, an FI9821W, didn't have any IR LED activity, just the flashing indicator LED and clicking.

I happened to have a nonfunctional unit of the latter in my closet at home and decided, after some research on Foscam's forums, to simply try swapping the AC adapter. That worked; the camera came back to life and began happily firing off motion alerts.

It would appear that in addition to various other problems with Foscam cameras, the FI9821W in particular, we can add AC adapter failure to the list. Out of curiosity I took the seemingly defective one and tore it down for inspection.

Foscam FI9821W AC adapter with label indicating specifications.

The top of the circuit board showed no obvious signs of failure; no scorch marks, no bulging or burst electrolytic capacitors (see here for more details), no melted or burnt electronics.

Cover removed to reveal the top of the circuit board and components.

The bottom of the circuit board revealed some clues. Multiple areas show telltale signs of melted solder flux, which could indicate overheating. Given that the camera expects a fairly consistent, specific voltage and current, overheating of the AC adapter components over extended periods could've bumped its output outside the tolerances the camera requires to operate normally.

Bottom of the circuit board. Note areas of solder flux showing evidence of possible overheating.

On the brighter side, replacement Foscam AC adapters are inexpensive and available online. If your Foscam wireless IP camera happens to die suddenly and exhibit some of the signs indicated previously, try swapping out its AC adapter and you might have a quick and easy fix. If you're feeling adventurous, it might be worth it to carefully drill some holes in the AC adapter casing to allow for airflow; in operation the AC adapter is quite warm to the touch.

A better long-term fix might be to invest in an Amcrest camera, given its better web UI usability, night vision, and better HD resolution, at least in the one unit I've had set up for a couple of months now.

One wonders if someone more business-savvy among Foscam's leadership actually wanted to invest time and energy into creating a camera that would actually deliver on features, usability, and quality in the form of Amcrest. So far my experience with it has been far superior to my trials and tribulations with Foscam, but we shall see.

Saturday, October 29, 2016

Samurai Sith

Lately I've been indulging myself in building a presence on Twitter. Part of this has involved creating an alter ego in the form of a Sith in the Star Wars universe with origins hearkening back to the samurai of some ancient time in a galaxy far, far away.

To this end, I wanted to set up a profile suited to such a character, an individual serving the Galactic Empire and the Dark side of the Force, yet at the same time having embraced the life of a samurai to some extent. I found my fictional muse in Yojimbo, a disenfranchised samurai (or ronin) played by the inimitable (though Nathaniel Lees of The Matrix: Revolutions fame comes close with his character aptly named Captain Mifune) Toshiro Mifune.
Movie poster for Yohimbo (1961).

I decided to create a representation of Jojimbo, the character, in a fictionalized alternative universe where, say, the political mastermind Emperor Palpatine managed to take hold of the formidable propaganda of the Empire and insinuate it into popular culture. To this end, I wanted to alter the original movie poster to give it a distinctive Imperial flavor, and hint that my Twitter persona aligned with this fictional manifestation of a great, individualistic, disenfranchised samurai.

There are certain physical attributes that make a Sith stand out from the inferior, frumpy Jedi. Being wracked by the powers of the Dark side, Sith experience increasingly drastic physical as well as mental changes. The irises of their eyes acquire an angry yellow glow; over time their flesh might wrinkle and fester thanks to their intimate embrace with the darkness.

Importantly, the weapon of Sith and Jedi alike, the lightsaber, acquires unique characteristics depending upon the user. TheStupendousWave provides a great explanation of the canon surrounding lightsabers and how the color those glowing weapons emit relates to their wielder. In the case of the Sith, they forego crystals found and refined from natural sources in favor of synthetic ones, which result in an angry red blade rather than the more tranquil-seeming blue or green typical of the Jedi.

To exemplify this in my version of the poster, I wanted to give my Yojimbo an angry red lightsaber blade, yet still have it retain the shape of the katana, the traditional weapon of the samurai. Further, I wanted to give his katana a hamon, a characteristic pattern along the leading edge of the blade. This site (natively in French) gives a number of examples of the different hamon in ancient Japan, some of which are depicted below.

Here (using Paint.NET, a great and free Photoshop alternative) all that needs to happen is to pick your hamon of choice (here I pick the Sukehiro hamon as it has a relatively tight and distinctive pattern), and crop it so just the blade remains:
Cropping the katana blade and copying it to the clipboard.

Then I paste it into the image as a new layer:

Pasting the katana as a new layer onto the poster, then rotating it to take the place of the original.

Finally, I paste another copy of the blade as another new layer into the image, and use levels to adjust the coloration of the layers along with glow effects and blend modes between layers to add a glow effect to this katana-slash-lightsaber. Of course, I use the superior, synthetic red glow of the Sith lightsaber here; use other, inferior colors at your peril!

The end result, with a few added elements (our glorious Emperor Palpatine, the Imperial logo, and the Sith's distinctive yellow irises) to make the poster a bit more relevant to the Star Wars universe, turned out nicely.

Nice addition to my Twitter profile, and perhaps speaks of an alternate reality where perhaps the Galactic Empire visited our world, insinuated itself into our culture, and happened to create a film about a Sith (with appropriate Imperial propaganda added to the mix, of course). 😈