A microcontroller is nothing but a computer, a smaller one for a specific purpose due to which it can also be referred to as “special purpose computers”. A microcontroller is a system with peripherals, memory and a processor that can be used as an embedded system meaning that getting a microcontroller,  won’t get you only the CPU but also the memory and different interfacing ports. Most microcontrollers that are used today are embedded in other consumer products or machinery including mobile phones, peripherals, automobiles and almost any other modern appliances.A microcontroller or also called “embedded controller” as are often embedded inside products and they can control the features or actions of the product.

Microcontrollers are often low-power devices. They are battery operated as they are portable and might consume 50 milliwatts as compared to the desktop computer that consumes 50 watts of electricity. Microcontrollers contain general purpose input/output pins. The number of these pins varies depending on the microcontroller and its architecture. They can be configured to an input or an output state by software, or even by corresponding signals in the pins. When configured to an input state, these pins can be used to read external signals or sensors. When they are configured to the output state, they can drive external devices like LED displays and motors. Usually most microcontrollers have built-in LED for output.

Microcontrollers are divided into categories according to their architecture, bits and instruction sets. So let’s discuss types of microcontrollers:-

Bit

• 8 bits microcontroller

• 16 bits microcontroller

• 32 bits microcontroller

Architecture

• Harvard Memory Architecture Microcontroller

• Princeton Memory Architecture

MicrocontrollerInstruction Sets:

• CISC (Complex Instruction Set Computer):It allows the user to apply 1 instruction as an alternative to many simple instructions.

• RISC (Reduced Instruction Set Computer): It reduces the operation time by shortening the clock cycle per instruction.

The microcontroller applications include large amount of machines, principally because they are simple to incorporate in a project or to assemble a machine around it. The following are the some of those applications::Light sensing & controlling devicesHandy medicinal gadgets such as glucose & blood pressure monitors Temperature sensing and controlling devicesFire detection & safety devicesIndustrial instrumentation devices for controlling industrial equipmentsHand-held metering devices.

Depending upon need, requirement, memory, number of I/O, peripherals and power management, availability, speed to process commands, one can select a microcontroller from its wide variety available in market. There are many Microcontrollers available in market like:

1. Arduino - Very easy for getting started, available with 8,16 bit

2. Microchip PIC - most robust, versatile, reliable, available in 8,16,32 bit

3. AVR - good for beginners, available in 8,16,32 bit

4. MSP430- good for beginners,  for low power applications, available in 16, 32 bit

5. Intel Galileo

6. RaspberryPi

7. 8051 series available, is a good start for students