Fade-in Background LED Lights for TV

I have always admired Philips Ambilight tecnology. Not only because it is cool but it is illuminating the TV from behind. This means that looking at the TV in total darkness is not such a strain on your eyes.

I have had LED strips from Ikea glued to the back of the TV for years now. It was time to add a couple more strips and to pimp up the system at the same time.

I bought a pack of DIODER LEDs from Ikea.

http://www.ikea.com/fi/fi/catalog/products/6011654...

They don´t cost much and in the package is everything included. My old strips were cold white and these new are warm white. Much cozier color.

I connected the four strips in series and glued them with hot glue on the back of the TV. Piece of cake!

The power distribution setup to the TV is as follows: Master/slave power switch (TV is master, PS3 and LEDs... are slave). When turning on the TV there is a surge which causes the LEDs to blink one time rapidly. This did not look good so something had to be made. Also the turning on of the lights is a shock for the eyes.

Below is a video of the blinking.

I used a very basic transistor + capacitor circuit to fade in the LEDs. There are a couple previous projects from me which are using basically the same circuit. You only need 2x resistor, one transistor and one capacitor.

Components list:

- 2x BC318A transistor is series (to double maximum power)

- 1x 1000 uF, 35V capacitor

- 2x 3k resistor (R1 and R2 in the link below)

The circuit has also the nice feature that it prevents the first surge from reaching the LEDs. So the circuit achieves everything that was planned.

The downside is that the transistor has to be in active mode instead of saturation. If it would be saturated, the first voltage spike would still get through and the LEDs would blink. So the LEDs are not at their full brightness but it does not matter. This problem could of course be sorted out but I do not see the urge to do that.

Here is a good link describing the circuit. I used the first circuit with the delay "problem".

http://pcbheaven.com/circuitpages/LED_Fade_In_Fade...

I have a 3D printer so it was obvious that it had to be used to make an enclosure for the circuit board. It is drawn with Fusion360 and sliced with Simplify3D. Printer is Flash forge creator pro. Material used is Octofiber red PETG. Print time about one hour.

This was a very easy and fun project to do. It costs basically nothing and you get so much out of the small circuit. In the video are the LEDs behind the circuit. The video is taken from the test phase. You can see under the TV the flashing of one strip that is not connected to the fade in circuit. In the final version all strips go through the circuit.