Week 10: Research on L293D IC

For this week progression I am now mainly focus on how to control the two DC motors for the prototype. As I have mentions the H-bridge for a few time in my previous blog. For this blog update I will focus on how the L293D actually work.

Image from: http://commons.wikimedia.org/wiki/File:L293D_Motor_Driver.jpg , accessed 17 May 2013

L293D is a H-bridge or motor driver use to control motor direction, enable and disable motor rotation.

  Motor drivers act as current amplifiers since they take a low-current control signal and provide a higher-current signal. This higher current signal is used to driver the motors.

 Image from: http://www.wvshare.com/product/L293D.htm, accessed 17 May 2013

By using the L293D H-bridge, tow DC motors can be driven simultaneously, both in forward and reverse direction. The motor can be controlled by the input at pin INPUT 1, 2 , 3 and 4 of L293D. (see above diagram)

Enable pin 1 and 9 must be set as HIGH in the code for the motors to start operating. This is to enable the motor to rotate. When an enable input pin is high, the associated driver gets enabled. As a result, the output become active and work in phase with their inputs. Similarly, when the enable input is low, the driver is disabled, and their outputs are off and in the high-impedance state.

Below table is the pin description for for L293D IC.

Pin Description: 

Pin No	Function	Name
1	Enable pin for Motor 1; active high	Enable 1,2
2	Input 1 for Motor 1	Input 1
3	Output 1 for Motor 1	Output 1
4	Ground (0V)	Ground
5	Ground (0V)	Ground
6	Output 2 for Motor 1	Output 2
7	Input 2 for Motor 1	Input 2
8	Supply voltage for Motors; 9-12V (up to 36V)	Vcc 2
9	Enable pin for Motor 2; active high	Enable 3,4
10	Input 1 for Motor 1	Input 3
11	Output 1 for Motor 1	Output 3
12	Ground (0V)	Ground
13	Ground (0V)	Ground
14	Output 2 for Motor 1	Output 4
15	Input2 for Motor 1	Input 4
16	Supply voltage; 5V (up to 36V)	Vcc 1

Diagram from: http://www.engineersgarage.com/electronic-components/l293d-motor-driver-ic, accessed 17 May 2013

Video from: http://www.youtube.com/watch?v=KnF0sRGWYtQ, accessed 17 May 2013

The video above show the 2 motors control by L293D IC. This is something that I would like to achieve for the prototype.