DIGITAL DC MOTOR CONTROL
ELECTRONIC PROJECT
This simple circuit lets you run a DCmotor in
clockwise or anti-clockwise direction and stop it using a single his simple
circuit lets you run a DC switch. It provides a constant voltage for proper
operation of the motor. The glowing of LED1 through LED3 indicates that the
motor is in stop, forward rotation and reverse conditions, respectively.
Here, timer IC1 is
wired as a monostable multivibrator to avoid false triggering of the motor
while pressing switch S1. Its time period is approximately 500 milliseconds
(ms). Suppose, initially, the circuit is in reset condition with Q0 output of
IC2 being high. Since Q1 and Q3 outputs of IC2 are low, the outputs of IC3 and
IC4 are high and the motor doesn’t rotate. LED1 glows to indicate that the
motor is in stop condition.
When you momentarily press switch S1, timer 555 (IC1) provides a pulse
to decade counter CD4017 (IC2), which advances its output by one and its high
state shifts from Q0 to Q1. When Q1 goes high, the output of IC3 at pin 3 goes
low, so the motor starts running in clockwise (forward) direction. LED2 glows
to indicate that the motor is running in forward direction. Now if you press S1
again, the high output of IC2 shifts from Q1 to Q2. The low Q1 output of IC2
makes pin 3 of IC3 high and the motor doesn’t rotate. LED1 glows (via diode D2)
to indicate that the motor is in stop condition. Pressing switch S1 once again
shifts the high output of IC2 from Q2 to Q3. The high Q3 output of IC2 makes
pin 3 of IC4 low and the motor starts running in anti-clockwise (reverse)
direction. LED3 glows to indicate that the motor is running in reverse
direction. If you press S1 again, the high output of IC2 shifts from Q3 to Q4.
Since Q4 is connected to reset pin 15, it resets decade counter CD4017 and its
Q0 output goes high, so the motor does not rotate. LED1 glows via diode D1 to
indicate that the motor is in stop condition.
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Thereafter, the cycle repeats. If you don’t
want to operate the motor in reverse direction, remove timer IC4 along with
resistors R5 and R7 and LED3. And connect ‘b’ terminal of the motor to +Vcc.
Similarly, if you don’t want to run the motor in forward direction, remove
timer IC3 along with resistors R4 and R6 and LED2. And connect ‘a’ terminal of
the motor to +Vcc. The circuit works off a 9V regulated power supply for a 9V
DC motor. Use a 6V regulated power supply for a 6V DC motor.
