Twinkle Twinkle Christmas LED Tree Star

Merry Christmas everyone,

My wife found a nice star for our tree, but wanted to have a few lights inside to give it some razzle dazzle root beer.

This is a very simple project to add some happiness in the form of LED's to an otherwise sad Christmas tree star... Sound illuminating?

To start, I decided to place one LED at each of the 5 points of the star, and a larger LED in the centre for a total of 6 lights.
The star was a yellowish colour, so I went with yellow LEDs.
If you wanted to get really fancy, you could incorporate an Arduino and an array of Adafruit NeoPixels or a NeoPixel ring for some really cool lighting effects.
This star is just of the plan ol' "light on" variety though. Next time... :)

I wanted to power it with a battery and since there will be 6 LEDs a 9v battery seemed most sensible.

I also wanted to give the LED's the ability of be dimmed, so I included a 10K Ω rheostat.

A quick sketch of the circuit then onto the breadboard to make sure everything is good to go and won't release any magical blue smoke when powered up.

Since there are 6 LEDs being fed from a single 9v battery, I need to wire them in parallel so each LED receives the same voltage and the current will be divided equally between them.
As an added bonus, if one of the LEDs goes nova, the others will stay illuminated, just increasing slightly in brightness.

The 220 Ω resistor acts as a safety, should the rheostat be set to zero, there is always at least 220 Ω of resistance.

Remember, don't directly mix LEDs of different colours (unless the exact same specs) or you might see the mysterious magical blue smoke. :)

Parts List

- x5 3mm LEDs - YELLOW
- x1 5mm LED - YELLOW
- x1 small prototyping board
- x1 10K Ω rheostat
- x1 220 Ω resistor - 1/4 watt
- x1 9v battery clip
- x1 9v battery
- Yellow wire

An afterthought, adding a small switch to the circuit would have allowed me to turn the lights on/off without having to remove the battery.

Assemble the components on the prototype board, then cut the board to an appropriate length.

I bent the LED leads 90° so the 'top' of the LED would face forward when the star was mounted on the tree (see the finished photo for example).

I then attached the finished circuit board and the LEDs to the star using a high temperature glue gun.

Note: Make sure the star material isn't conductive, or otherwise shorting out your LED leads.

I used yellow wire to connect each LED in parallel back to the 9v battery source.

Once the glue has cooled, place the star in your tree, attach your 9v battery and enjoy the eternal glow of LED Christmas.. or at least until the battery runs out...

Safety First: Make sure that nothing gets hot or could potentially short out, you don't want a heat source on a dry Christmas tree. Major fire hazard.
Always disconnect the battery when not in the room, treat it as you would a real candle.