Let's Make Robots!

L293N Motor Controller

I'm trying to build a DC motor driver for my new Adruino and i'm very new to all of this. I'm going to use the L293N motor driver and I'm trying to figure it all out with this tutorial.



I'm going to be running two geared 143:1 gear motors which can be found here



I would like to solder everything to a PCB board similar to the one in the tutorial. I have quiet a few questions and many of them I feel embarrassed to ask.


1.  I'm pretty confused with what is positive and what is negative.  The diagram shows only one line which directs the current.  Obviously that is not right.  I understand that pins 1 and 9 need a negative charge and pins 8 and 16 need a positive charge.  Please correct me if i'm wrong.  It must have more than one wire where is shows just one red line right?

2. The diagram shows the micro-controller and the motor driver being power by the same power supply.  I thought this was a bad thing to do.  We do have the 5v regulator in place, so that makes it okay right.  I just don't want to fry my chip.

3. What is the the black power out regulated thing for?  Is the two pronged thing to power the microcontroller?

4. What are the blue things called for for the power in and the two motors?  Also what is the two pronged power out regulated thing called.  I just need some names as i start to look up parts to purchase.


Any help would greatly be appreciated.  Thank you so much. 


Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Pins 1,8,9 and 16 are positive

pins 4,5,12 and 13 are gnd

A shared power source will be ok for small motors. The schematic assumes that you have added the needed parts to the regulator --i.e. the caps and wiring (the diagram does not show a gnd on the regulator for example). Your arduino board probably has a regulator on it, if it has a jack for a power cord, it has a regulator.

What is the the black power out regulated thing for?  Is the two pronged thing to power the microcontroller?

This one is a little tougher. The 2 strips, upper left -below the red led, are for 5v regulated power out as is the 2-pin white connector on the right edge of the board. If you scroll down on the post, everything on the board is labled. There is also a picture of an arduino plugged in to the motor driver chip.

Screw terminals are the blue things. --Be sure to buy .1" pitch.

I can't remember what the white connectors are called. J-connectors maybe? I dunno. Just look under connectors anywhere you shop and you will find them


Now, with these kinda questions, you might want to simply make a board for just the motor driver and skip the regulator. If the arduino board has one, there is no need for another. You will need to decide what type of power source is right for you. I know some arduinos use 9v batts, but these are not good for motor run time. 3 or 4 AA's would be better. I can't say much more without knowing what you want to do.

Also, I would suggest to build this on a breadboard instead of soldering it. Radio shack even sells PCB's with traces that match the set-up of a breadboard -- this makes it very easy when you want to finalize what you are doing.


You say:

Pins 1,8,9 and 16 are positive

pins 4,5,12 and 13 are gnd

I'm still confused on what is negative and what is positve.  I have no experience with circuts and i'm just not sure how it will hook up with the battery.  If 1 8 9 and 16 are positive what does the negative part of the battery connect too?  Sorry for the really stupid question.

I probably going to put it all on a breadboard first to make sure i get it working and then to a PCB.  My power supply will consist of a 4 x AAA battery holder.  I'll just do a 2 pronged power out to power my microcontroller. 

I found this 100uf/16v capacitor, but digikey had a TON of different ones.  Does it really matter which one i use?



Thanks Always!

Start with something simple, as you have no idea what to do.


pins 4,5,12 and 13 are gnd (ground)

In terms of what capacitor to buy. I'm not sure which cap you are refering to. I would say that you should get your caps and resistors from Radio Shack --R.S. has sort of a limited supply thus they sorta carry only "standard" parts. Just be sure to get the right value and note if it is polarized or not.





I don't want to hold you back from your projects but I have to say that if you didn't know that gnd (ground) on a circuit like this notes negitive, you may want to start with a simpler project to get you going. The standard is to get your microcontroller to blink a LED as a first step.

well now i know i guess.  I've done the easy stuff with my microcontroller like making the lights blinks etc... I'm guess i'm going head first into this because i don't have very much money and can't spend much on other experiments.  I'll try looking around for some cheap and easy things for building some basic circuts.  I appreciate the help.