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.

I wouldn’t know how to program it but you could try playing around with a photo resistor like this or this. But I think that will only work if you have constant light conditions. Maybe an IR light barrier with a reflector on the other side would work better.

No idea if what you want is possible but that would be an awesome project.

@mykle1 Pretty much the same as yours. Before was around 62-65°C and now I am around 41-42°C under pretty much the same conditions. And for the noise: You can barely hear the fan if you put your ear right next to it. I am pretty pleased with the result, especially for the price.

@sdetweil
That didn’t help in my case, hence the work-around with the cronjob. But it’s true that everybody should first try to disable the update module in their config.

I finally received my heat sinks and had the time to play with my second Pi (3b+, not my mirror-Pi, which is just a 3b).

The heat sink is fixed to the CPU via heat conducting double-sided adhesive. It’s a small surface but it holds well. The 30mm 12V fan is connected to the 5V and GND of the Pi. That’s enough to get it running and it’s totally silent. The airflow is enough to keep everything cool.

To fix the fan to the heat sink I just used some wood screws. Didn’t have any nicer looking ones…

Costs:

• list itemFan 1.17€ from Aliexpress
• list itemHeat sink: 1.16€ (for 5 pieces) from Aliexpress, You can also buy just once but I will use the others for other projects.
• list itemHeat conducting adhesive: 1.08€ for 48 pieces (25x25mm). You can buy less but I also use it for other projects…

I have the same problem. A Ctrl-R helped getting the modules back but I didn’t like doing it at least once a day. Therefore I created a cronjob that reloads the MagicMirror everyday at 6am. Haven’t seen a black screen since then.

Not a fix but a work-around.

One if the cleanest setups I have seen so far. Well done!

Make sure your location ID still exists. I had to change mine a couple of times since January this year.

Maybe contact the guy from here (Goldjunge_Chriz). In his post it says the max size is 120x80cm to ship to the UK. Maybe you can ask him if he can make an exception.
It’s not cheap (way too expensive for my taste) but the results look spectacular. Additional to that it is thin and therefore light.

Maybe he’s able to ship to the UK if you pay extra. Should be still below 500€ altogether.

That’s why I run mine from a cheap SSD (Kingston A400, 120GB iirc). Much faster and no risk of corrupting it. I paid 27€ for my SSD. At this price I think it is worth considering buying one.