Anwar’s Blog

Finally, the job of building the circuit is over. I mounted the breadboard on top of the car and connected the motors and sensor board cables to it. I used a 9V power supply for it. Now with all the colourful wires etc, it just looks cute.

With a lot of enthusiasm, I switched on the power supply.

Nothing happened

I switched it off and then switched it on again

It refused to start

This was bad. It just didnt start. The motors were fine. I checked electrical continuity of all connections with my multimeter. Everything was fine. I tried programming the microcontroller again, but that didnt help either. Everything appeared to be fine but it didnt work for some reason. It stayed at rest, shamelessly lighting up the four LEDs connected to the sensors. Even the main LED didnt light up(I’ve checked, the LED is fine). I felt like giving it a hard kick.

In terms of the time, energy and money spent, it was too expensive to be kicked. So I gave up the idea.

I think I’ll spend the next day trying to figure out the problem.

Some more progress….

There are only a few more connections to be made. I guess it has become too bulky. Lets just hope it works…

The work has gone a little further. Some more connections were made.

The breadboard now looks a bit messy. I dont think I could do a neater job. The motors are now mounted on to the base of a Toy Remote-Control car. As this car previously had only one motor, there was no proper space to fix two. Therefore I had to make use of adhesive tape.

The sensor board now sits in what was previously the battery box of the car. The two wires seen with the red tape over them power the board. Four more wires connect each of the four sensor assemblies independently to the main board. Thus there are a total of six wires connecting the sensor board to the main board.

The LIRC Project gave me enough confidence to connect something home made to the computer. So, I went ahead with the BlowIt programmer. I hope it was success.(It says the programming was successful but I am yet to try the led blinker program, kind of “hello world” of electronics.) I then decided to try my hand at a line follower robot I found here :
http://www.kmitl.ac.th/~kswichit%20/LFrobot/LFrobot.htm
It follows a black line(of considerable thickness, not just a line drawn with a ball pen) drawn on a white surface.

Before I start, I must admit that I have ZERO understanding of the program it uses. I just downloaded and copied it straightaway.

To buy all the components, I had to visit the Gujrati galli at Koti again and spend a good amount of money, aroung Rs. 350. The circuit is fairly simple and all the schematics can be fount on the page mentioned above.

It uses 4 sensors, each consisting of an IR emitter and an IR receiver. The sensors can detect whether the surface underneath them is white or black in colour, and guide the robot accordingly.

Here are the first pictures :

First few components. Starting from left, the first IC(connected to the blue wires) is LM7805, a constant voltage regulator, powering the whole circuit with 5volts. The second (between the four red LEDs) is LM324N comparator. The third is the AT89C2051 Microcotroller(here i have fixed the μC socket for reference of pin numbers. The μC is still on the programmer. The fourth(extreme right) is the L293D motor driver. It was the most expensive of all the components used.

The sensor board, containing 4 sensors.

I plan to remove motors from 2 of my toy RC cars and use one of those two cars as the body of my robot.

Here is my first device programmer, made at home! This is a simple programmer and has no extra features like code verification or reading code from the chip. It can program only three devices - atmel AT89C2051, AT89C4051 and AT89C1051. I built the whole thing on a bread board. The circuit is very simple and easy to make and its quite inexpensive too.

Here are the costs -
Microcontroller(AT89C2051)                                    Rs 35
Electronic components, wires, connectors etc         Rs 50
Bread Board                                                                  Rs 30
Total                                                                              Rs 115

I found this on the following sites :
http://www.geocities.com/dinceraydin/8051/
http://www.lecad.uni-lj.si/~leon/electronics/bi2051/index.html

Thanks to the writers of both the pages and the person whose idea this whole thind was.

Here is the circuit schematic :

Some Pictures

Picture of my programmer.

The Parellel port connector.

There are 3 or 4 different software for writing programs to the chip.
BlowIt for DOS
PY2051 (for windows)
GNU BlowIt (for Linux)

PY2051 was not running on my computer for some reason. I couldnot install GNU BlowIt on my ubuntu ultimate 1.8. So I used BlowIt for DOS, for which iI had to boot into dos mode. I did this by using my old bootable Windows98 CD.

I am now a proud owner of a PocketPC. I got this I-mate PDA2k as a gift. here are a few pics :

It has a 3.5″ touch screen and a full size keaboard. It is powered by a 400MHz processor and has 128 MB of RAM. It has bluetooth, IR, WLAN(802.11b), SD card slot and a VGA camera. The picture quality is good enough for quick shots. Now this is what you call a great phone.

Learning to program microcontrollers is easy. Thanks to microcontroller simulator softwares, you dont physically need microcontrollers or the hardware to program them. Tese softwares emulate the behavior of several microcontrollers. PIC Simulator is one software which can emulate microcontrollers in the PIC series. I downloaded the trial version of PIC Simulator IDE from http://www.oshonsoft.com/pic.html .

The IDE is quite easy to use. You can either use BASIC or Assembly language. Compilers for both are rovided with this. Really nice piece of software I would say!

I found a really good collection of free E-books on almost all the topics here.

http://www.onlinecomputerbooks.com/

Remote controlling a PC using an IR remote is a good idea. The required IR reciever is simple,cheap and can be built at home. The circuit diagram, PCB design and the software(both for Windows and Linux) can be found at www.lirc.org . In Hyderabad, all the components can be easily found at Koti and it costed me around Rs 60.

Soldering kit and a few components

IR Receiver. Connected to the PC through the COM port.

The remote I use. The cut out circuit board of the receiver is also seen.

WinLIRC Software

I use WinLIRC to decode IR signals, Girder (www.promixis.com) to control applications, and WinLIRC2Girder Plugin to connect WinLIRC and Girder

Aren’t those snapshots more annoying than they are handy? The pop up every time you place your cursor over a link.

They are enabled in wordpress by default. I decided to do away with them.