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Brief Intro to Various Components Used in Arduino & Raspberry Pi

Basic Electronic Components used for Arduino and Raspberry Pi projects are listed below


A Resistor is a component that resists the flow of current. It’s one of the most basic components used in electronic circuits.

Resistors come in a variety of resistance values (how much they resist current, measured in units called ohms and designated by the symbol Ω and power ratings (how much power they can handle without burning up, measured in watts). The resistor could be connected with any of the two pins as there is no positive or negative pin.


A Breadboard is used to build and test circuits quickly before finalizing any circuit design. The breadboard has many holes into which circuit components like LED and resistors can be inserted. A typical breadboard is shown below:

To use the bread board, the legs of components are placed in the holes. Each set of holes are interconnected row wise and column wise. The top two and bottom two column wise holes are used for ground or power supply. As shown in the figure, see how the 5V and the ground holes are interconnected column wise.

The holes that lie between the first two and last two are interconnected row wise as shown in the figure below. Can u see the LED and the resistor connection? The rest of the circuit is built by placing components and connecting them together with jumper wires. The components like LED, resistor etc are placed in the middle of the board so that half of the legs are on one side of the middle line and half on the other. The simple circuit model is shown below,

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 Light-Emitting Diodes (LED)

A Light Emitting Diode – or LED for short – is a component that can give light. We use LEDs to give a visual feedback from our circuit.

For example to show that the circuit has power. But, we can also use them to make cool light-show circuits. We see these components everywhere: In our laptop, on our mobile phone, on our camera, in our car. And we can find many different types of LEDs. A very common circuit to build as a beginner is the blinking light circuit. The Longer pin is the positive one (to be connected with the power supply) and the shorter one is negative pin (to be connected to the ground).

The connection for the LED with Arduino is shown below, 

Light Dependent Resistor (LDR)

As the name says, it is a resistor that depends on light. It increases its resistance when it no light falls on top the resistor and its resistance decreases when light falls on it. I suppose still you wouldn’t have understood.

Now let me explain you with an example, when we connect an LED with the LDR, the LED blinks when we block the top of the LDR with our finger. When we remove the finger, the LDR blocks the flow of current and the LED stops blinking. It could also be used as street lamps also where the street lamp starts working when the sun sets and the street lamp stops when the sunlight falls on it.

The LDR has two pins. The Longer pin is the positive one (to be connected with the power supply) and the shorter one is negative pin (to be connected to the ground). The connection for the LDR with Arduino is shown below,

Temperature Sensor (LM35)

The LM35 also known as Temperature Sensor that can be used to measure the temperature in Celsius. We can connect the LM35 to the Arduino via the breadboard and we can get the temperature readings.

It is a 3 legged Sensor wherein one is for power supply. The first pin is for power supply, the second one for the output and the 3rd pin to the ground. The connection can be done as shown in the figure below,


It also called as a Beeper. It just used to produce a single tone whenever a voltage is positive. We could use it for many purposes for example, if the temperature goes beyond 40C, the buzzer will beep else it is silent.

It consists of two pins. Longer one is for positive or power supply and the smaller one for the output. The connection for the Buzzer with Arduino is shown below,

IR Sensor

An Infrared sensor is an electronic device that emits in order to sense some aspects of the surroundings. An IR sensor can measure the heat of an object as well as detects the motion. It is a 3 pin sensor. As shown in the figure below, the first pin is for Power supply or 5V, second one for Ground and the last one for output.

The connection for the IR sensor with the Arduino is shown below,

By using an LED which produces light at the same wavelength as what the sensor is looking for, we can look at the intensity of the received light. When an object is close to the sensor, the light from the LED bounces off the object and into the light sensor. Now the sensor has detected an object as shown in the second figure.

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PIR Sensor

PIR sensors allow us to sense motion, almost always used to detect whether a human has moved in or out of the sensors range. Every object that has a temperature above perfect zero emits thermal energy (heat) in form of radiation. We, Homo sapiens, radiate at wavelength of 9-10micrometers all time of the day. The PIR sensors are tuned to detect this IR wavelength which only emanates when a human being arrives in their proximity.

They are commonly found in appliances and gadgets used in homes or businesses. They are often referred to as PIR, “Passive Infrared” or “IR motion” sensors. The pin description is given below,


The connection for the PIR sensor with the Arduino is shown below,


Potentiometer or POT

The POT is a variable resistor that can be used to adjust the intensity or values. For example, the intensity of the LED blinking can be controlled by the POT or the beep sound from the buzzer can also be controlled. We can control through as shown in the figure below, the adjuster with our finger nails or screw driver as the knob is quite tiny.

The connection for the POT with the Arduino for controlling the LED is shown below,


USB Cable

The USB cable is used for Arduino as an interface between the Arduino and the computer. It serves two purposes, one as a power supply for the Arduino board and the second is to write and upload the program to the Arduino board. It also called as A-B cable.


Jumper Wires

Jump Wire is a short electrical wire with a solid tip at each end, which is normally used to interconnect the components in a breadboard. They are used to transfer electrical signals from anywhere on the breadboard to the input/output pins of Arduino.

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