How to make a light-tree from a piece of tree and a lot of LEDs.

This make combines both natural materials and the very much synthetic. I like copper on wood, I don't like PCBs.

The video shows what you can do by twiddling the "Dial-a-LED" controller, otherwise there are 10 fixed configurations, and 2 off-positions.

Step 1: Materials & Tools

A piece of wood (Hawthorn) from the woods.
Some local stones
A copper ornament / tourist souvenir
An unusual Japanese telephone
A USB cable (for a camera, from before card-readers were common)
Red micro LEDs 10x from the slider-bars of an old stereo
Yellow 5mm LEDs 8X from old Christmas-tree lights
Green 5mm LEDs 8X from old Christmas-tree lights
Violet/UV LED (bought)
Solid-core bell-wire
Solid-core mains cable (30A)
Some capacitors from an old stereo

A drill
A soldering-iron
Screwdriver
Scissors / knife
2-part epoxy glue
Car body filler (styrene / polyester resin)

Step 2: LED Assembly

Simply drill holes in the wood to accommodate the LED "legs".
In this sequence I've drilled holes for 10 tiny red LEDs, one hole for each pin. Friction was enough to secure these, although glue could have been added.
Wire the LEDs in series pairs with bell-wire (see schematic)
The leads to the left are for the +ve supply, the leads on the right for the ground (-ve).
Later the GND leads will connect to a big copper bus-bar, the +ve wires will be guided down to the base and secured.

Step 3: Power-bus Assembly

Strip the insulation from heavy mains cable to release the copper core.
Bend to shape
Drill holes in the wood to accommodate.
The copper "object" was blasted with a heatgun to melt the solder that held it together and a of the few pieces were used to join the bus-bar together at junction points
The images show the ground (-ve) metalwork, the +ve power buses were made from bell-wire.
The copper is all friction-fitted, no glue required.

Step 4: Continue

Drill more holes, add more LEDs.
Connect the LEDs to the ground (-ve) bus bar, and run the positive supply down the wood with bell-wire.
At the bottom of the of the wood, terminals were fashioned from copper "pegs" inserted into drilled-holes. The copper was cut from the mains cable to ~¹/₄", and friction-fitted.

This is quite good fun, as you build the design around the material. Where your wires go is something of a natural development.

In most cases the LEDs were secured by friction, or attachment to metalwork, but a few were secured with glue.

Where +ve supplies were run under the GND bus, a small amount of glue was added as precautionary insulation.

Step 5: The Base

The piece was lightly-screwed to a small piece of hardboard, then secured with filler.
Some stones were added, pressing into the filler while sticky, for weight and aesthetics.
The screws were removed when the filler had hardened.
The stone adds plenty enough weight to keep this upright.

Step 6: "Dial-a-LED" Controller

The odd phone I found on the market was based around a double-pole 12-position switch.
I removed the switch and connected the LEDs as shown in the schematic
Some capacitors were added to soften the switch-offs, and some low value resistors to restrict current.
The outputs were soldered to a cable connector from an old video, allowing the tree to be unplugged easily
An old USB cable was stripped, the ground connection connected to the ground (-ve) copper bus, and the (red) +5V wire fed to the rotary switch via a second switch (just because it was there)

Step 7: Schematic

The violet LED is running at about 10mA it's fine. I've applied a green design with fluorescent marker-pen on the wood, but it's not possible to photograph it (not with my camera anyway)
The micro LEDs run just fine too.
The green and yellow LEDs were originally restricted with 39 Ohm resistors, but were a little underpowered so these were removed. This is why there are 0 Ohm resistors in the schematic.

I've represented the two parts of the switch side by side, they are on top of each other, and each have a rotating arm connecting the centres to the outer terminals.