Digital Bike Tachometer Circuit


Posted on Feb 6, 2014

This digital DIY tachometer for bikes uses two reed switches to get the speed information of the bicycle. The reed switches are installed near the rim of the wheel where permanent magnets pass by. The permanent magnets are attached to the wheelspokes and activate the reed switches everytime they pass by it. The speed is digitally displayed. The ta


Digital Bike Tachometer Circuit
Click here to download the full size of the above Circuit.

chometer circuit works according to this principle; the pulses created by the reed contacts are counted within a certain time interval. The resulting count is then displayed and represents the speed of the bike. Two 4026 ICs are used to count the pulses, decode the counter and control two 7-segment LED display. RS flip-flops U3 and U4 function as anti-bounce. The pulses arrive at the counter`s input through gate U7. The measuring period is determined by monostable multivibrator U5/U6 and can be adjusted through potentiometer P1 so that the tacho can be calibrated. The circuit U1/U2 resets the counters. Since batteries are used to power the circuit, it is not practical to support the continous display of speed information. This circuit is not continously active. The circuit is activated only after a button is pressed. At least three permanent magnets must be installed on the wheel. The circuit can be calibrated with the help of another precalibrated tachometer.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Soft Start For Amps
    Logic probe
    Design and making of the stabilized voltage supply of switch
    PWM Speed Control Circuit Using Forward-Reverse and Regenerative Braking
    Ultrasonic parking sonar circuit design project
    Switchable Output Crystal Oscillator
    ds1820 interfacing with avr primer
    Fade or gradually eliminate style lighting controller circuit
    Based NJM2701 3D surround audio circuit
    Lamp remote control circuit
    Automatic washing machine motor driver schematic



    Top