RGB LED Light

[paulca]

My temporary, WIP LED monitor backlight began to fail after about 3 years.  It's looking like the power brick has gone bye bye, cutting out every few minutes.  5V, 10Amp, been running 16 hours a day for 3 years at 3.6Amps.  Cost me £30.  Seems like a rip off.

Anyway, I liked it.  I liked it so much I want to do another one and better this time.  Longer and just as bright.  Less temporarily permanent.

To that aim the plan is to basically double it.  But to move up to 12V WS2811bs.  I don't need individual pixel accuracy for an indirect light!  Groups of 3 will be fine.  That will save me from playing games with 5V DC bricks with "stupid amps".

So, 144 pixels per meter, 2 meter length.  Glued to an aluminium strip of the same length.  Along the back of the strip will run 16AWG wire such that the strip can be powered at both ends.

The 1m 5V strip pulled 3.6A at full bright white.  Regardless of what the scary theoretical draw is (9 amps).  A direct conversion to 12V should mean it pulls 1.2A (based on 3 in series) or 1.5A based on voltage scale alone.  Doubling the length brings that up to 2.4A.  So I am going to pick a 12V, 5Amp brick and spend a few quid on it as it will be in use 16 hours a day.  12V @ 2.4/3.0A ~= 30-36W which sounds about right at full whack for what I need.

For "Digital control" I have a few Aurora dongles which take 5-12V power in one end and put out the 3 pin WS2811 signal.  They run WLED.  This WILL NOT take more than about 2 amps through it before its soft fuse cuts out.  However with a little modification I can supply the 12V directly to the LED rails with 16AWG cable and run the digital only on a branch.  Not even connecting the + and - outputs from the dongle.

The purpose of this light, I should have started here.  It runs along the back of my monitor panels, yes they are long enough to hide 2 meters of LED strip.  They shine up the wall and onto the cieling and provide the only ambient light in the room.  The fact they can be switched to odd mood colours and even do animations like water rippling is just a bonus.

A further bonus use is that the strip controller has a REST API.  I can, from software alone, signal things via these lights.  Alerts for example like motion at the front door when a parcel arrives etc.  I can "blink" the strip red for 250ms for one thing and green for another.

[ahsrabrifat]

Since your setup will run 16 hours daily, a high-quality 12V, 5A (or slightly higher) power supply will be a good choice.