Holla !!

Well, as you know, I am now in engineering college , and as most others in this field, I have been interested in the technical aspects of things. Just a month ago, I attended a Robotics Society introductory lecture in our college and decided to take up robotics, both for a learning experience and as a challenge.

Well then, here I was : a newbie with no prior knowledge of Electronics ( having studied computers) and not knowing where to start…So I asked around,took a bit of help and chalked out a plan of action ..

Maybe this sounds a lot easier than it actually is..or maybe its even easier…But anyways,here it is :

1. What to make :

I decided to skip the first two levels of robotics (wired remote controlled and wireless remote controlled ) because I thought them to be easy ( stupid,ain’t I ?) . Well, I decided to make a computer controlled wired robot.

2. What I need :

I had to do a lot of asking and reading and deciding, partly because of my inexperience and partly because of the sheer variety of stuff available….But finally, I made it…The list was ready !!

3. Go get ’em :

This part was pretty easy… I asked my seniors and came to know there was an entire road (can you believe it !! ) selling electronics stuff…I got recommendations on where to get the best stuff at the best prices and I went and got it….

Click here to read the list of all the stuff I used…

4. The HOW :

This was slightly tricky…I tried to put it all together in parts,trying to make it work…but again, it wouldn’t work…That was probably because, as my friend pointed out, I hadn’t read the data sheets well (That actually means I hadn’t properly figured out how my stuff works and how to get the best out of it..)..Well, I did that ,and finally put together AND got it to work…Boy, what an achievement !!

Here’s the scheme of my circuit :

(Courtesy :

Pins 8 and 16 get a 12V supply.
Pin 9 gets a 5v Supply.
Pins 4,5,12 and 13 are grounded.
Pins 10 and 15 act according to computer controlled signals,taken from the parallel port.
Pins 11 and 14 go to a DC motor.
All these are essential for running ONE motor.
If you want to use two motors simultaneously, you also need to make sure:
Pin 1 gets 5V Supply.
Pins 2 and 7 get input from the computer.
Pins 3 and 6 go to the motor.

Also, you will need to figure out how the L293D motor driver works…I had problems figuring it out…Click here to download the datasheet of the L293D ..Its also available freely on the Internet…

To take inputs from the computer, you will need to solder wires to a parallel port male connector and plug the connector to the printer port of your computer.

You are going to use the pins D0 to D7,so you must learn how to program the computer to give proper signals on these pins. You can use any four of these pins for two motors.A powerpoint presentation of this robot can be found here.

Here’s how the male connector looks after soldering :

THE Computer programming :

I wanted my bot to be user controlled…i.e. the key pressed by the user determines where the bot goes…so I again scoured the internet, found a useful C function, and wrote a simple program.
This program will keep on taking user input till you press the q key (make sure CAPS lock is off, dunno if it will work otherwise), after which it will exit.Am providing a sample program, however, you must change the ouportb commands to give outputs depending on your motor configuration, as the wiring will also play a part here. Fiddle a bit and figure it out. Click here to download the C code.

/*/*/* I have modified the C code in the file above,so please check it again.The older one does /*/*/* not work !!

Since I have used the bioskey function,I needed to find the values of the various keys.
Here they are : (Make sure Num Lock is on)

1 ————->20273
2 ————->20530
3 ————->20787
4 ————->19252
6 ————->19766
7 ————->18231
8 ————->18488
9 ————->18745

5. The Niceties :

Well, I have never been good at this part… I am still working on it…But here’s a rough look…

I know its not at all neat….Too much of crisscrossing wires and no clarity…But anyways…

Here’s a video of my bot in action :

You can watch it here if you can’t open it.
What I did was probably the easiest project in the whole world, but even so, if anyone wants to try this and is facing some problems,please feel free to ask..I MAY be able to solve them…

Resources :

1. Links : I found all my links from my college robotics website : VJTI’s SRA

2. Stuff : I bought most of the electronic goods from Visha Electronics on Lamington Road and the DC motors and wheels from Servo (I am told they’re the best),again on Lamington Road. The whole stuff put me back by some 2500 bucks…

Visha Electronics : Phone : 23862650 or 23862622
Servo : Phone : 66346573

3. Software : Parmon is a useful little software which allows you to control the outputs of your pins. Links are available on the society website.If you wanna program your bot to do some extra stuff, you gotta know “C” programming.You can download it from the geekhideout website by clicking here.

4. for the diagrams of the L293D and and the parallel port connector.

Will be back with more exciting(read geeky) stuff,

P.S. : Thanks to Raghav , Param and Sachit for all their help and advice


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