Heart Beat Sensor

Heartbeat sensing technology was developed as an offshoot of a security system developed by a national laboratory to protect nuclear power plants. In that application, security officers set up a station at the plant entrance. There, they attached two sensors called geophones to every vehicle entering or leaving the lab grounds. The geophones measured sounds in the vehicle structure, and software in a portable computer analyzed them to determine whether the vibrations matched the patterns of a human heartbeat. No matter how big the vehicle, these heart pulses set up a distinctive vibration that the sensitive geophones were able to detect. Ford Motor Company engineers and scientists have been able to shrink that military technology to the size needed for commercial applications, using two super-sensitive micro-accelerometers instead of the bulky geophones.
The principle remains the same the sensors measure minute vibrations in the vehicle structure, and matches them against the known sonic pattern of a human heartbeat. It is able to screen out other common vibrations, such as those induced by truck traffic, road construction jackhammers or gusty wind. It is so sensitive that it can detect a person anywhere inside a vehicle. Even someone simply touching the outer skin of the body. Since it doesn't work via line-of-sight, there's literally no hiding from it, which is a major advantage over heat or motion detectors, which leave blind spots in coverage and are vulnerable to defeat.
The system will alert the driver to a child or anyone else left inside the vehicle when it is parked and locked. After a brief delay, the system will sound an alarm if it detects anyone in the car. The system is activated by the lock button on the key fob. This guards against a child being forgotten inside the vehicle on a hot day. It also would sound the alarm if a dog or cat were left inside, since their heartbeats are sufficiently similar.
The system also offers an innovative security feature. In a typical scenario, the driver returns to the parked vehicle after shopping at a large mall. The system allows the driver to "query" the vehicle from a safe distance via the fob. In a few seconds, it scans for vibrations and tells the driver whether anyone is in the car