Help with my direction control

Discussion in 'Homework Help' started by vliang, Mar 9, 2010.

  1. vliang

    Thread Starter New Member

    Mar 9, 2010
    Hi, i am trying to build a radar circuit which track the signal source and i cant build a working direction control for the circuit. My whole set up was an antenna on a DC servo motor. And it is control by a chip where the pin was grounded, the motor turn left and when it is connected to a 5v, it will turn the other way round. And the power level of the antenna is as below and i used a threshold to cut the signal from Antenna into TTL logic input.lets call this A.

    There is also a tachometer attached to the motor which I turned it into a TTL (lets call it T) logic when it is 1, it indicates the motor turning right, vice versa. So i think T is much like a storage of previous 'output'.

    To make sure the antenna point correctly (well, not really accurately, i set a range of dead zone), i want to build a TTL circuit which changes the direction when A =1 and let it continue its direction if A =0. T indicates the previous output.

    I tried to build a design like a show below,
    The truth table will be
    A T output
    0 0 0
    0 1 1
    1 0 1
    1 1 0

    but sadly, the circuit did actually keep changing its state, i guess it is changing between the last 2 due to some time delay.

    can anyone please help me to solve the problem? use synch circuit? or T-flip flop whenever A is 1?