摘要 |
PURPOSE:To provide a speedometer for bicycles which can correctly measure a running speed without requiring any special sensor. CONSTITUTION:In the speedometer for bicycles which is constituted so as to digitally display a running speed of a bicycle, a waveform of an alternating current output from a hub dynamo 1 for lighting a lamp 10 fixed to the bicycle is converted into a pulse wave by a protecting circuit 12 and a waveform- forming circuit 13. A running speed of the bicycle is measured by a microcomputer 14 based on an interval of the pulse waves and a peripheral length of a wheel stored in an internal RAM beforehand. |