I am trying to control the bi-directional spin of motor using a switch.
I have connected this circuit using an Arduino UNO, a SN754410 Motor Controller and a 540 DC Motor sold by TamiyaUSA.
The Circuit and the Arduino Code are found in the following link:
I am using a regulated 5.4 V supply to the motor. I have tried the experiment with 4.8 V and 7.8 V regulated power supply to the motor too.
Now I upload the code to the board. Then, I connect the terminals to the Motor.
First, the motor starts running. Then, it stops. In other instances, the motor starts running. I change the direction of the motor using the switch. Then, it stops.
After it stops, there is a low "krrrrrrrr" sound coming from the motor. If I disconnect the motor terminals and reconnect them, but it doesn't start. However, if I wait for about 10 mins and try it again, it starts and stops all over again. And the sound is still there.
The Motor is not over-heated. None of the circuit elements are over heated (thanks to the heat sink on the regulator).
Also, directly connecting the power source to the motor makes the motor spin (very fast) in one direction without any overheating. So, the there is no damage to the motor.
I have even tried adding a decoupling capacitor of 100 micro Farads across the Motor, but it hasn't changed anything.
Please let me know if I am doing something wrong.
Also, any suggestions on how to make the design more efficient. For tomorrow, I am thinking about adding an Op-Amp voltage follower before the motor terminal. Why? Well, before connecting the power outs from the Motor Controller to the motor terminals I have a +/- 5.4 V across this power out controlled by a switch (for forward and backward motion). But, after I connect the motor to the power outs the voltage difference drops to about 50 to 100 mV.
Also, if you know of a better way of bidirectional motor control using the same elements (atleast the same board and chip), please post.
I thank you all for your interest in advance.
I will check back daily for the next couple months to answer any replies.