Basic Robotics Kit (L293D) part-1


When i was in my very early semester of college, I was very passionate about robotics. I was always confuse about where to get cheap PCB layout which one can use in several different robotics project. while writting this article, i am recalling and thinking about that time and realizing that that was not only me. There were several hobbyist like me, who were confuse, wanted to save money but wanted to take part in robotics competetion in college technical fest.

And this is also true that when a student starts to make robot, he/she needs basic component like sensor module with LM393 comparator, Motor driver PCB, wireless module, remote module and so on. This is also true that the PCBs for these modules which are avaiable on internet or any other stores are much expensive, when compared to an IC which is providing the main functioanlity.

That's why, i tried to made these modules for a basic robotics which include L293D motor driver and IR sensor module. Especially, in my home town colleges, these components were so famous because in every technical fest of each college, there existed some robotics chalenges which required these modules.

Now, I will tell you one by one about each PCB board which i made for robotics.

L293D module Description

If you dont know at all about L293D motor driver IC. I recommend you to study about it here. In this board, i have attached 4 LEDs which also shows the status of each input provided to L293D. Two left LEDs tells about the direction of Left motor and similarly, rights ones are for right motor.

There are two power supply jacks, where one (near 7805 regulator) is for powering L293D itself and other one is for the custom supply to the motor. Recommended voltage is in between 5-20 volt.  Both the side, you can find the male connector to connect DC motors. With this, there is also a 6 pin male connector for data band, either from any microcontroller or a remote control in case of manual controlled robot.

6 pins description is like this:

Pin number (Left to right) Function
1 To short the ground in case of MCU and power supply Vss for MCU
2 Power supply +5 volt / Vdd for MCU
3 Input 1 pin for L293d (left Motor)
4 Input 2 pin for L293d (left Motor)
5 Input 1 pin for L293d (right Motor)
6 Input 2 pin for L293d (right Motor)


In the 6 pin data band, 2 MSB (Most Significant Bits) are always same because they are output from L293D board. So as the data value in Hex the input value vary from 0x10 (0b010000) to 0x3F (0b011111). To Operate motors, consider the following cases. We will also seperate the data bits seperatly, so value can be rewritten as 0x00 to 0x0F.

Data value States
0x00 Both motors are free
0x01 Motor right will reverse
0x02 Motor right will move forward
0x03 Brakes on right motor
0x04 Left motor will reverse
0x05 Both motor will reverse
0x06 Left motor will reverse and right motor will forward
0x07 Left motor will reverse and right motor will stiff
0x08 Left motor will move forward
0x09 Left motor will move in forward and right motor in reverse
0x10 Both motor will move forward
0x11 left motor moves forward and right will brake
0x12 Brakes on left motor.
0x13 Braking on left motor and reversing right motor
0x14 Braking on left motor and forwarding right motor
0x15 Brakes on both motors

So, i this way, either we can send this data by a microcontroller or, we can generate binary quilvalent bits by a remote control. For any doubts, feel free to shoot me an email.