Systems, devices and methods of using motion detectors and temperature sensors inside vehicles for activating alarms to protect vehicle occupants that include babies, children, infirm, elderly and pets. Headrest mounted motion detector(s) and a temperature sensor detect both motion and selected temperatures to remotely transmit alarm signals to the vehicle horn that can play an SOS alarm. The detectors and temperature sensor can sound alarms when unsafe cold and warm interior vehicle temperatures are reached. Low battery indicators such as audible alarms, chirp sounds and lights can be used to indicate low battery power supplies.