DC motor not spinning with L293D motor shield

[okbro]

I am making a bluetooth car using arduino and L293D motor shield which is shown in the picture below. I applied various power sources, like wall socket with 9V adapter, 12V from lithium ion batteries etc, I get connected to the bluetooth but the motors are not spinning. I have another car which justs works fine, that is, which uses geared motors and 12V from lithium ion batteries. So I know the code is fine and the connections are also fine. Do I need to use geared motors? All others aspect is the same for the two cars(working and non-working).

Thanks

 

[rjenkinsgb]

Do the motors spin if you hold it clear of the ground?

If the problem is just too little torque (due to them not being geared) they should work when not loaded.

If they still do not turn, it's an electrical / wiring / software problem.
If they do turn without load, it's because they do not have gearing and are not powerful enough without it.

 

[alec_t]

Without gearing the starting current of the motors will be greater. Perhaps some over-current protection feature is kicking in?

 

[okbro]

I tested and reported here with wheels clear above the ground and they did not turn on at all. The same program code works with my another car with geared motor.

how to check whether this is over-current protection feature problem?

thanks all

 

[Nigel Goodwin]

Just measure the voltages - is there power from the L293D feeding to the motor?, is there power actually feeding the L293D?, and are all the control signals in place?.

It's a very simple circuit, and easy to fault find - get a voltmeter round it.

Write some simple code to spin one motor in one direction permanently, and trace voltages for that L293D/motor.

 

[tepalia02]

Test the motor separately. See if that is really functional or not.