Day 17: Controlling a DC motor

I bought this car in a second-hand-stuff shop. Originally it was remote-controlled but when I bought it, it no longer had the remote control. I don’t know the motor specification. This car has five AA batteries (7.5V), so I think it is safe to use my 5V power source. I put it on a box to avoid it to run away.

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This time I used the L293D attached to GPIO 18 and 23 in a way I can make the motor run forwards or backwards.

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I used the Servo Blaster library as presented on Day 14. In order to run the motor forwards, I kept one signal at zero and changed the other one.


echo "2=0" > /dev/servoblaster

echo "5=500" > /dev/servoblaster

To run backwards, I inverted the signals:


echo "5=0" > /dev/servoblaster

echo "2=500" > /dev/servoblaster

It worked with values from 300 to 2000.

When the motor runs forwards, the white LED is on. The LED is connected after the L293D.

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When the motor runs backwards, the green LED is on. The LED is connected before the L293D.

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