Abstract: A child safety system is described which senses when a child is left alone in an automobile and alerting others. One implementation includes a weight sensor pad for sensing a child's weight applied to an infant car seat, a transmitter to transmit, to an alarm device, an alert signal when a child is in the seat, and a driver door switch. The alarm device generates an alarm signal (e.g., a loud siren noise) if a baby is in the seat after the door switch indicates the driver has left the car.