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Can anyone help me with the connections of the below shown Dual H-bridge L293D motor driver with the Raspberry pi 3 to drive DC motors?

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I don't have much experience in Electronics as I am a CS student.

The website doesn't show any details like pins etc

TI L293D Datasheet

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    Is there no information on the website? Have you got a photo which shows the pin labels so they can all be seen and read? – joan Oct 11 '16 at 15:56
  • The scribd document is behind a paywall which not many will be prepared to pay to pass. I dislike the scribd site. – joan Oct 12 '16 at 7:44
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It's two full bridges. You put the left motor between AL and BL, and the right motor between AR and BR.

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Without documentation (or someone who has one which is working) you are going to have to experiment AT YOUR OWN RISK.

I would feed motor power in via the green power block. It should be marked +ve and -ve or Vcc and ground.

I would connect the two motor leads to the left motor block at the top right. One lead to AL and the other to BL.

I would connect two Pi GPIO to the two pins marked (I think) left motor at the top left of the board.

I would connect a Pi ground pin to one of the GND pins above Vcc and BL at the top right of the board.

I would then offer a prayer to your God(s).

Set the two GPIO you are using as LOW outputs (i.e. write 0).

Then set one GPIO high and leave the other LOW. The motor should turn.

Change which GPIO is high and low and the motor should turn in the other direction.

  • If this is a single layer PCB (which I think it is) it should be easy enough for the OP to follow the traces from the pins you mention to the respective pins on the L293 chip. With the datasheet of the chip they should then be able to verify your proposed wiring without putting the Pi at risk. – Ghanima Oct 11 '16 at 19:16
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    I agree, depending on the OP's level of knowledge. Personally I'd just stick the L293D into a breadboard, it looks like it is socketed. – joan Oct 11 '16 at 19:43
  • The bottom picture clearly shows connecting the motor to the 'left motor'/'right motor' connections of the board, and if you connect the 'two Pi GPIO to the two pins marked (I think) left motor at the top left of the board.' you will fry the pi. – Pete Kirkham Mar 9 '18 at 15:23
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The guide you posted tells you where to supply power (DC jack or Wago connector, 'Description..' section 2), and to connect the motors ('two output connectors' 'Description..' section 3, 'two pin motor output connector' under 'H Bridge motor interfacing')

As the chip is four half-bridges, each half bridge is controlled by an input (). I would imagine that the inputs labelled AL and BL are the half bridge inputs for the left motor and AR/BR the inputs for the right motor. They do not seem to have exposed the two EN inputs, so you won't be able to do free-wheeling PWM control, only switch between 'run' and 'brake'.

On this assumption, the effect of the inputs should be:

A   B   result
0   0   brake ( motor outputs both connected to ground )
1   0   forward ( one output at +ve, the other connected to ground )
0   1   reverse ( one output at +ve, the other connected to ground, opposite way round to above )
1   1   not used ( motor outputs both connected to +ve, should also brake )

You can PWM by switching between forward and brake, but it will result in more heating in the chip than PWM using the enable pin would. This is probably not a problem if the motor isn't close to the rating of the driver.

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