Abstract: A speedometer capable of providing real-time speed signals, that can be combined with different functional devices and speed control units, to facilitate the automatic recording and controlling of the speed, thereby forming a multifunctional automatic monitoring and controlling device for vehicles. Photoelectric sensors are disposed in the conventional mechanical magnet-type speedometer, and a LED is mounted on the speed indicating needle shaft. The ON and OFF states of the LED can be controlled by a signal from within or from external of the vehicle. The output of the photosensors are connected to a multichannel photoelectric converter.