Let's Make Robots!

problems with L293D + Arduino

I wired up a L293D to my arduino, planning to run 2 motors with it, and just for testing I runned the blinkie program on it changing the LEDpin to the to the digital pin that goes to the l293d but only half of the pin works, like it turns in only one direction. Is it normal ?


It's 4 in the morning so I did not do a lot of trouble shooting, just changed the pins that were on PWM to digital, it didn't changed anything.

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Thanks for your help.

How do you remove the Flux? I've tried with an old toothbrush and it doesn't work, the flux is quite hard.

soap and water, and then a blow dryer afterwards. Takes a bit, but it does come off. Just don't look at some of my old boards, that I forgot to clean.
I've checked Pin 1 and 9 the +5v is getting there, i still have to check the PWM outputs. I'll varnish my table and  will come back to ou with the infos.
I think he said he figured it out and it works now :)!

I said a lot of things ; )


Sorry no updates, I haven't worked on it. I have a lot of thing to do like varnishing a new table for my elctronic workplace that I'll ruin with solder drops, so I maybe update tomorrow I don't know.

Switch the connections from the Arduino to the motor driver. Does this make the other motor work? If so, could be a initialization of the PWM pins that is not occuring, and only one set is actually driving the h-bridge.

Another possibility is that there may not be a good connection between power and pin 1 or pin 9 on the L293. If you have a meter, might be good to test each pin (on the chip side) to see if +5v is getting there. You could also check the PWM pins to see if an output is being generated.

You say that becaus you haven't seen the other side of it. ; )

though, I tought that by making it clean and everything it would have been easier to trouble shoot/modify.

I should have posted a picture of the first one i made too, it was so small, but again it was impossible to modify.


here it is! It's not that ugly I may be a bit anal about my cricuits...


I like how your motor controller is clean :)!

I guess it can be something like:

- your power source isn´t enough to drive 2 motors

- some bad connection

- code


can you post a picture of your setup?