@adrien That should still be possible with the script method described in 5.1. Instead of the power lines for the controller board of the LCD you use the cables that lead to your backlight.

I don’t know what LCD you have. Some have an extra inverter or LED driver board. You can take the cables from there. Some have a 40 pin LVDS cable (instead of 30 pin), so you have to check the datasheet which wires are for the backlight. I’d take the VCC wire for the backlight, snip it and connect both lose ends to the relay. That should work.

Keep in mind that with this method the LCD is always on, only the backlight is off.

@adrien check out this forum thread. cruunnerr explains different methods on how to turn on/off your screen. He helped me setting up my system which uses a relay and PIR-sensor to power on/off my LCD. I think that’s what you’re looking for.

@striiker Could it be the screensaver? Have you tried updating to 2.5.0 or downgrading to 2.3.x? I am pretty sure I didn’t have the problem with 2.3. In my case it’s enough to reload the MM only once a day. Also I had noticed that my Pi was reeeeeeeaaaaaaallllllyyyyyyy slow when connecting via shh after the screen blanked. Slow to the point I thought it crashed. Pretty sure it was a memory leak or so.

I haven’t updated to 2.5 yet as I want to wait and see what problems other users experience

Never got it to display anything. Page could not load or something like that. Not on the Pi0 and also not remotely on another PC. After many attemps and long hours of troubleshooting and reading I finally gave up on it.

I really would love to get it working though as I’d like to make another cheap mirror for my brother as a present. Still have a two-way-mirror lying around…

Why are you running the update command with sudo?
Does your mirror work but it blanks the screen after some hours or is it always black?

@graham-rich to update your MM installation you have to enter your MM directory and run git pull && npm install. Looks like you tried to update npm instead.

@striiker 0 6 * * * pm2 reload mm
It reloads my mm.sh script every day at 6am. Working perfectly fine for quite some time now.

@teitlebot Of course. Just wanted to show a possible “cheapest” way. It always depends on your budget and skills/age of your students.

No need to go for the LCD controller board path if you get working screens.

I think you have to be lucky to get an old eeePC for just $11. Let alone multiple of those. Have a look into RasPi alternatives like Orange Pi. They are a bit cheaper and I think there’s a forum thread here somewhere of people running MM on it. The Pi0 would be probably the cheapest alternative but I’ve never managed to run MM on it…

Of course a cheap laptop is the easiest way to go if you can get enough for cheap. An old laptop for $25 is still cheaper than a RasPi and already comes with power supply and screen.

I just felt like setting something up and take a picture to visualize the whole thing better.

For my actual mirror I use a V59 controller board which is great but it costs more. The board I linked above can control a large number of screens that run on either 3.3V or 5V. It can’t handle 12V panels, though. AFAIK 12V panels are mainly used in larger screens like TVs. Regular computer screens should use 5V. Anyway, always look for the data sheets before connecting the board to the LCD.

The LED driver for the LCD backlight generally needs 9-30V input. Since the LCD controller board only provides 5V I am drawing 12V directly from the power supply.

Somehow can’t add pictures so just click here!

For the LCD you can ask at your local recycling center if they have a bunch of old monitors they’d be willing to donate to the school. Otherwise try places like Craigslist or so. You should find old 17" LCD screens for around 5 bucks. If they are not working, but the LCD panel looks ok, you can buy very cheap universal LCD controller boards like this.
The board runs on 5V so you also need a power supply. Try to find cheap 12V power supplies. Those to drive LEDs are generally very inexpensive. 25W should be enough per MagicMirror, but it greatly depends on the number and size of the CCFLs of the LCD. Use a 12V-to5V DC-DC buck converter. I have this one and I can also use it to power my RaspPi.
You’ll also need either an inverter or LED driver for the backlight. I am not linking a product here because it depends on the number of CCFL’s/LED strips but they should generally be less than 2 bucks a piece.

You’ll also need a HDMI to VGA adapter and if you don’t have a VGA cable, something like this.

That’s my input from the LCD side of the project. Let me know if you need help or have any questions. I only posted AliExpress links but you can check any other places of course. Check out eBay, Banggood.com, Gearbest and so on. Make sure you do some searching to always get the best price! Especially if it has to be as cheap as possible.

Edit: fixed mainly typos.