Showing posts from March, 2015

How a computer starts: Behind the scenes

We all use computers pretty much everyday, but have you ever wondered what happens when you switch on a computer. Let us go behind the scenes and find out what happens inside the computer.

First of all the CPU performs a procedure called "booting" when the PC is turned on. The instructions for this come from BIOS(basic input/output system), a program stored on a flash memory chip (BIOS chip). Under booting the PC first performs POST (Power-on self-test). POST is a small program contained in the BIOS that checks for hardware failures. When the test is successful, the BIOS then locates the bootable drive to load the boot sector. The execution is then transferred to boot-loader (a computer program that loads an operating system) located in the boot sector. 
Booting is of 2 types: Warm and cold.
Warm booting: This booting takes place when a PC restarts. In this case the system does not start from the initial state, hence the diagnostic tests need not be carried out. This type of…

Arduino controlled programmable bluetooth robot

I did not build a robot or write about robots for a really long time. In fact I didn't even write a blog post for a very long time now. So, today I am going to write about a robot that I had been working on for past 4-5 days. This robot uses an Arduino as its brain and has an HC-05 bluetooth module for sending in commands through a smartphone. The main focus here in this robot is the ability to automate its motions. A user can enter a string of letters and instruct the robot to mimic the step commands entered. For example a user can enter "ssrst" which means move forward 2 steps then turn right and move one step forward again.The 't' is to instruct the robot to perform the set of motions only once. If the 't' is not entered the robot will go on executing the motion. These short-forms may seem difficult to remember but come in handy when the robot has to do a lot movements. I am presently working on an android application also to make it easy to send comm…