1. The document describes a vehicle theft prevention system that uses a GSM modem. When an unauthorized person tries to unlock the vehicle door, a microcontroller detects the event and orders the GSM modem to send an alert SMS to the owner's phone number.
2. If the owner replies with the text "stop the engine", the microcontroller activates a relay that disconnects the vehicle's ignition, stopping it. This system aims to stop vehicle theft using wireless technology instead of GPS tracking.
3. The system was tested and found to successfully send an SMS alert to the owner when unauthorized access was detected, allowing the owner to remotely stop the vehicle if it is being stolen.