Cozy Bedroom Lighting 2 (Star LED Curtain)

To add some smooth consistent light of the flickering Lanterns of my last Instructable, i decided to create an LED curtain in a star pattern, to cover the whole ceiling.

Since i really liked how it turned out and i discoverd a few stumbeling blocks, i decided to create a step by step guide, so you can avoid my mistakes.

Supplies

Materials:

LED Curtain (i used the yellow version of this curtain)
Full Bridge Rectifier (GBPC5008, 50A/800V)
Resistor(~470KΩ)
300V 100μf Capacitor
Housing (I 3D Printed this)
Fasteners (i used small hooks)
heat shrink tubing (or other means of isolation)

Tools:

Soldering Iron
wire cutter
superglue
3D Printer (optional)

Step 1: Analysing the Circuit

It is important to note, that this Instructable only works with the LED curtain i used - or a different curtain, that uses the same circuitry.

You can determine if your curtain will work, if the voltage used to drive the LEDs is approximately 230v. The circuit will therefore contain no transformer or other kind of power conversion. If your circuit operates at a different voltage, skip the "rectifier" step in this Instructable and connect an appropriate powersupply instead.

Step 2: Prepairing the Strands

use the wire cutter separate all 16 Strands form the curtain and identify the + and - leads. This can be done by using a multimeter. The resistance in the wrong direction should be close to infinity.

Now take 4 Strands and connect them in series by soldering the positive lead of the previous strand to the negative lead of the subsequent one.

Make sure you isolate all your solder joints appropriately - I used heat shrink tubing.

You should end up with 4 bundles of strands (4 strands connected together in each bundle).

Now connect all bundles in parallel.

Each bundle should have one unconnected positive lead and one unconnected negative lead. Connect all 4 of those positive leads and all 4 of those negative leads together. Do not isolate those 2 joints jet, as they will be needed to connect the strands to the rectifier.

Step 3: Building the Rectifyer

The rectifying circuitry is used to convert the 230v ac signal into a 230v dc signal.

It consists of a full bridge rectifier (a diode arrangement that converts the AC sine wave into dc halve waves), a capacitor to smooth those halve waves into a continuous signal (this removes flickering) and a bleeding resistor.

The Resistor has two different purpuoses. It ensures the capacitor gets fully discharged when the device is unused and it bleeds small amounts of charge that might accumulate due to capacitive coupling of the wiring, even if the light is toggled off. (this manifests as a faint continuous glow of the LED strands)

Since the used capacitor has a high capacitance, the rectifier needs to be able to withstand a high power draw for a short amount of time, as the capacitor will draw a lot of current during its first chargeup. I therefore used a beefy prebuild rectifier that is rated for high current.

The actual creation of the powersupply is quite trivial.

The negative lead of the capacitor (the marked side) needs to be connected to the negative terminal of the prebuild rectifier - the positive side to the positive terminal.

The bleeding resistor will be added across the terminals of the capacitor.

to finalize the electronics, connect two cables to the input terminals of the prebuild rectifier (they will be connected to mains) and connect your led strand assembly to the corresponding outputs.

Step 4: The Housing

i designed and printed this housing. If you don't have access to a 3d printer, you may want to use a small project box or something similar. If you are using the 3d printed enclosure, you can prepare your cables while the enclosure is printing:

Start by separating all 4 bundled of strands again.

Use zip ties to hold the cables of each bundle together.

Now arrange those four bundles into a large bundle and use zip ties again to hold everything together.

The pre separation is done, because it arranges the different strands in a more fitting position to hang them later on. (i tried it without before and it was a mess).

Place everything inside your enclosure and test fit.

If you tug on the strands, the force should be transfered by the zip ties to the housing.

If this is not the case, place another zip tie on the bundle of cables further down and test again.

If you are happy with the fit, apply a small bead of cyanoacrylate (superglue) along the edges and press the enclosure together.

Check the alignment and hold everything in place using painters tape.

When the glue has set, remove the tape.

If you nave any spots where the glue has smeared, you may try to remove them using aceton.

Step 5: Application

The application strongly depends on the type of your ceiling. Please ensure you use appropriate fasteners. I went with regular wood screws.

Connect the lamp to your mains wiring.

If you also have the Lanterns from my last Instructable, connect them too. -

The enclosure has enough space too also hold their powersupply.

Now push the enclosure upwards and ensure everything is tugged in nicely.

If you have a wood ceiling, you can now screw Everything in. If it is made out if concrete, you will need to mark and drill holes first.
once the enclosure is secured, you can place the fasteners for the strands. I used 1 hook per strand and screwed them in with an equal distance to the wall.

This causes the strands to hang at different heights in the end, since the room is square and the strands will effectively form a circle.

I placed 1 strand in each corner and spaced the rest of them evenly.

Once the hooks are screwed in, the strands can be slippend over them with the desired amount of tension. A higher tension will hold the strands more firmly and closer to the ceiling. Less tension will allow the strands to form arks.