People ask, why should we learn micro controllers? There are many answers. Some of them I am writing here.
Human brain desires comfort. It tries to avoid doing the same things again and again. To avoid this boredom and to live comfortably, many (though not all) gadgets are designed. At the advent of electronics, precise control of such gadgets is possible.
Let me give you an example. Washing clothes was (or is) a drudgery. So washing machines were born. Making them automatic has made us more comfortable. Precise control over them and making them automatic is now possible with micro controllers. This not only allows us to be lazy but saves resources like water, soap and electricity.
Micro controller executes instruction every micro second. So the whole function of a gadget is broken down in small parts. Each small part is done by a single instruction. This is how micro controller works.
To measure physical quantities, controllers are used. Now a days, ADCs (Analog to Digital Convertors) are built inside the controller chips by default. To measure temperature for example, connect a temperature sensor to the ADC chanel. ADC will convert the analog voltage to its digital (binary) equivalent. This binary number is further processed and displayed by micro controller.
Micro controllers are becoming cheap. I remember buying a chip (Intel 8051 with UV erasable eeprom) for Rs. 800 in 1992. Today we have somewhat better feature pack chips of same architecture are available off the shelf for less than 40 Rs. This tells that the cost of silicon brain is going down. Why not take advantage of it? Also pass on this benefit to the final user.