@hoofta Couldn’t you use a relay (like me) but instead of disconnecting the power you just trigger the power on/off button?

https://www.ebay.com/itm/1PCS-DC-DC-LM2596-power-Supply-Buck-Converter-step-down-module-NEW-CA/142147326064?hash=item2118a41070:g:L1kAAOSwvzRXzOBg
or
https://www.ebay.com/itm/DC-DC-Buck-Step-down-Regulator-Converter-4-2-23v-to-3V-3-3V-5V-9V-12V-24V-Module/112472493337?hash=item1a2fe20d19:g:dCsAAOSwdd9aVjD6
should do. They are adjustable via a potentiometer. Iam using the latter one for a Pi Zero but the 3A are enough to power a Pi3 easily. You should check aliexpress.com since most of the low priced parts already come from China. They will be even cheaper and are the very same product.

Don’t be afraid to ask…

Pic says more than a thousand words…

You can solder the wires together but that’s not really needed.

Just use luster terminals.

You split the 12V output of your power supply. One set of wires (plus and Gnd) goes to your LCD controller board (check polarity!) and one set to your step-down-converter, which is regulated to 5.1V for the Pi.

That should be enough for all if you don’t have more than the LCD, Raspberry Pi and the step-down module. You should check the power consumption of the LED strips, if you’re planning to use some. If not, you should be good with 30W.

Yeah, I saw after I replied. I checked the datasheet and if I do not misunderstand the information, your screen should be at around 10W (max.). The board will probably take some, too. But you should be more than fine with a 30W power supply.

Here’s an example from my LCD that I am going to use for my mirror

The M240HW01 V.D. is the LCD model and AU Optronics is the manufacturer.
Btw, for the future: A V56 or V59 controller board are already available for less than 8€ incl. shipping and the firmware can be changed easily by USB. It has other disadvantages though, like not waking up automatically once the HDMI port is re-activated.

Ah ok, I also of one of these to fire an old Laptop LCD for a digital picture frame.Now we need to know the type of the LCD. You can write it when you’re back home and I’ll look at it asap. Probably tomorrow since it’s already 7pm here.

I can’t open that link because it links to your personal order details.

Edit: If it’s a universal LCD controller board (like the V29, V56, or V59), then it also depends what LCD panel you’re using? Can you give me the panel number? Should be a sticker on the back of it. I’ll have a look at the datasheet.