I've been working on a security project which contains an Arduino Uno, LCD display, Alarm and a 433Mhz receiver.
It all used to work fine until I needed 12V for my alarm. I use a 12V power supply and use that throughout the project. My electronics skills are really limited and so please excuse any plain mistakes or poor explanation.
I've created a diagram in fritzing and attached it to this post. At first it works fine (several seconds) but than the LCD starts to act weird and the 433Mhz receiver doesn't work anymore.
Could you please take a look at the diagram and check if you see any obvious faults? I'm not sure about the 12V and 5V lines with the common GND. Do I need to create separate circuits?