A simple but nice LED ornamental mobilé to hang into a window.

Supplies

Tools:

Materials:

Brasswire 0.8mm thickness (2.5m ~ 8')
Yellow LEDs (4)
Thin Plywood (4mm ~ 1/8")
String (1m ~ 3')
2 Core Wire (1.5m ~ 5') or 1 Core Wire (3m ~ 10')
9V Battery
9V Battery Connector
Shrink Tube

Step 1: Cut and Twist Brass Wire

Cut the brass wire in length of about 60cm ~ 2'. Lock one end in the chuck of a drill and hold the other end with the pliers, pull the wire tight and twist it about 1-2 per cm ~ 3-5 per inch. This work hardens the wire and makes it easier to work with and a bit more resilient / springy.

Step 2: Form the Wire Ornament

Start the forming with a double loop matching the LED diameter, it should fit tightly around the LED.
Then using your fingers and the round nose pliers create an ornamental spiral, that suits your liking. On loose spirals I like to return the end back to the top and solder it to a place near the top, to have no free end and give the spiral some more rigidity.

Step 3: Create the Housing

I cut a triangle with about 120mm side length from thin plywood and 3 side pieces about 25mm in height. Thin plywood can easily be cut with a utility knife. Make sure the side pieces fit around the center piece, then secure 2 corners of the side pieces with masking tape. Spread woodglue on all touching sides and fasten all pieces in place with clamps or rubberbands. Let it dry for at least 30 minutes.

Step 4: Assemble LEDs

Cut all LED pins short, keep the anodes a tad longer. Cut the wire to different lengths between 20cm and 40cm. If using single core wires like me, twist the pairs using the method from step 1. Strip the wire ends and apply some solder to them, then solder them to the pins. Make sure that there is a safe air gap between the uninsulated parts and keep the pairing the same (in my case blue/red wire is always on the anode).

Step 5: Assemble Circuit

After sanding (and finishing) the housing drill 4 holes 3mm ~ 1/8". One in each corner and one dead center.

Pass the LED wires through the holes use some paper clips to keep them assembled. Make sure u are happy with the composition of the wire length, if you want to shorten or reorder them this is the time.

Solder the LEDs in series anode to cathode, insulate all connections with shrink tubing. Solder the 9V battery connector into the series (red wire to anodes).

Test the circuit with a 9V battery.

Step 6: Attach Strings

Cut the string into 3 equal parts. Use superglue or hotglue to attach a string to each corner. Lift the mobilé up by the strings, make sure the housing hangs level, twist the strings together and tie a knot in the center and another at the common end.

Now connect the battery, put it in the housing and hang it in your window.