Jun 9, 2020, 1:16 PM
Post #1 of 1
Switch TV backlight on/off to save energy
I am new to this forum but found your advice very helpful in the past, so thank you first of all!
I would like to build a MagicMirror using a TV.
To save energy, I try to utilize a PIR sensor to turn on the backlight of my TV whenever someone walks by. The LCD panel however will always be on and emitting the HDMI-signal from my RaspberryPi. This solution should allow me to have a TV picture that's instantly on and does neither need to boot nor show the TV logo nor show the input source.
This problem has already been discussed but does not really help me to much since my hardware setup is different.
What I did so far:
My screen has an integrated LED driver on the power board (BN44-00460A). I tried the following:
1. Unplugging the LED backlight (Connector: CNL802).
Result: The TV reboots in a continuos loop
2. Disconnecting the "BLU on/off" pin on the power board (Connector: CNM803) that controls the backlight unit from the main board (Connector: CN201).
Result: The backlight is always on
Where I need help:
* Does someone know another way of maybe tricking the software of my board to think the LED's are on without them being on? I thought of utilizing a resistor but this does not really save me energy.
* Any other ideas?
* Worst case, I need a new used TV: Does someone know which TV (32" or bigger) has a separate LED driver or allows the backlight to be manually switched on or off. I could do this using a relay or via a 5V pin as proposed in the related issue described above.
Thanks a lot in advance, I greatly appreciate it!