L293D - Motor Driver Walkthrough

In this walkthrough I will show one simple way to use L293D H-Bridge, and build a basic Motor Driver for Arduino. I only tried this with Arduino Diecimila and it works well.

There may be other ways to do this, but since this works for me and feeds my needs, I assume this might be useful for more people.

NOTES:

- 9V little batteries are good to power the Arduino, LED´s and one or another sensor, but not so good to power DC motors or servos;
- If you want to have more devices, like another motor, servos, sensors, it is better to have a stronger power supply like an RC Car battery pack, or, AA batteries together with 9V battery and in this case you should connect both GROUNDS;
- be very carefull when dealing with power supplies, sometimes small mistakes may cause short circuits and damage your MCU, sensors, motors.. and you don´t want that!
- If you see something wrong with your motor, like stop, stall, or erratic behavior maybe your battery needs to be recharged, or your battery is not supplying enough power to your motors. Always use your batteries fully recharged;
- If you see erratic behavior in your servo, like going into one direction and staying there, or becoming noisy maybe it needs more current to operate, or your battery needs to be recharged.

So let´s start:

L293D gives you the possibility to control two motors in both directions - datasheet

Pins 1, 8, 9, 16 - POWER           Pins 4, 5, 12, 13 - GROUND
Pins 2, 7 - Input 1                     Pins 3, 6 - Output 1
Pins 10, 15 - Input 2                 Pins 11, 14 - Output 2

The picture shows:
- one motor connected to IC pins 11 and 14.
- IC pins 10 and 15 connect to the Arduino PWM pins 5 and 6. Using PWM you are able to set different motor speeds.
- The Arduino is being powered from USB. Note the jumper next to the USB plug is set to USB Power mode.

CODE Sample

Here we have a different setup:

- Note the jumper next to the USB plug is set to EXTERNAL power supply.
- The batteries pictures are symbolic. You should design your power setup regarding the MCU, motors and servos current needs. Ask in the forum what best fits your hardware.

Breadboard example:

The L293D only drives motors. Servos are driven by the MCU or Servo Drivers.

Below are some examples of custom made motor drivers assembled in prototype boards:

This board can control one motor, supply power for Arduino, and one servo.

This board can control two motors, supply power for Arduino, and two servos.

This board can control two motors, supply power for Arduino, and two servos.
I also added female headers to supply power for other components (ex: sensors, …)