“Essentially it is about the same idea like in my previous instructable:
https://www.instructables.com/id/Home-Security-With…
The only change is use of Orange Pi board (my choice was PC2) and one 4050 level shifter to protect boards IOs.
To sum up - a cheap home security system that sends you emails with pictures of your possessions when someone visits your appartment unexpectedly. A system which is easily armed and disarmed the more conservative way than you could expect - a switch and a RFID tag. Sorry, I like it a lot ;-)
You can get an Orange Pi for 10$ , a USB camera maybe 2$ (actually I use two clumsy junk ones!), the rest maybe 30$ all together.
To be more specific about what you need - an OPi board, its power supply, 74HC4050 level shifter, one or more PIR motion sensor, a RFID reader, a momentary switch, two LEDs, 2x 220Ohm + 1x 10kOhm resistors, a breadboard and cables for connecting all together, and USB cameras of course. “