Design of Infrared Digital Tachometer

Conference paper
Part of the Lecture Notes in Electrical Engineering book series (LNEE, volume 246)


This paper introduces the design of the non-contact method to measure the rotational speed. Compared with the traditional mechanical method and magnetic method, more convenient and efficient for future speed measurement is of great significance with measure the rotational speed of the object with a photoelectric. The design circuit includes photoelectric conversion circuit, 1 s pulse generation circuit, 60 s frequency multiplication circuit, counting latch circuit and decoding display circuit. Pulse waveforms is produced by photoelectric conversion circuit, after a Schmitt trigger wave shaping, the pulse waveform excite latch working, by the circuit latch, decoding, display, finally the mechanical speed will dynamic display on the common cathode 7-segment digital tube.


Photoelectric conversion 1 s Pulse generating circuit 60 s Timing and latching circuit Decoding and displaying circuit 



This research was supported by the Tianjin natural science fund (13JCYBJC15800).


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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  • Jingrui Sun
    • 1
  • Mingcheng Liu
    • 1
  • Jincheng Wu
    • 1
  • Li Zhou
    • 1
  1. 1.College of Electronic and Communication EngineeringTianjin Normal UniversityTianjinChina

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