The oil exchange warning apparatus which uses number of revolution of the engine crank shaft

摘要

Disclosed is an apparatus for warning of an oil exchange time using RPM of an engine. The apparatus comprises: an amplifier configured to amplify a voltage of a pulse waveform produced from a power supply according to revolution of an engine as a signal having a desired size; a comparator configured to compare the signal received from the amplifier with a reference voltage and convert the signal into a digital value; a counter configured to count RPM of an engine based on the signal outputted from the comparator and count the RPM of the engine accumulated until a reset operation is performed; and a display configured to display the oil exchange time using the RPM of the engine counted by the counter.