car alarm

anyone who knows about car alarm ideas and circuit please inform me imediately

Two excellent alarm circuits on this site.
A simple but effective loop alarm:
https://www.electro-tech-online.com/threads/the-oscilloscope.56/
A more sophisticated modular alarm:
https://www.electro-tech-online.com/threads/audio-perimeter-monitor.57/
Regards.

I looked at https://www.electro-tech-online.com/threads/the-oscilloscope.56/. ElectroMaster, if you read this, you might want to comment, since I'm critiqueing your circuit.
I believe the base resistors are way too large. The LED is going to draw around 7ma. The buzzers that I could find specs on draw at least 5 or 6 ma. That's 12 ma collector current. The base current is about 38 ua. For the transistor to saturate, you will need beta to be over 300. This is not common in a garden-variety transistor, certainly not at low Vce, which is where the operating point is. I would make the base resistors no larger than 22k. 10k would be safer.