My Android Things

Android Things Tutorials (IoT)

Tutorial 6 : Hardware Components Needed for Our First Project

Hardware Components

There are different parts you would typically need to build something with Android Things (or any other IoT platform for that matter) depending on what you want to build.

Breadboard - A breadboard is a solderless device for temporary prototyping/Testing circuit designs. A breadboard is a rectangular plastic board with a bunch of tiny holes in it. Most electronic components in electronic circuits can be interconnected by inserting their leads into the holes.




The columns on the edges of the breadboard are connected vertically by conductive metal strips, and the inner rows are connected horizontally:




To interconnect the selected row (node A) and column (node B) a cable going from any hole in the row to any hole in the column is needed:




Now the selected column (node B) and row (node A) are interconnected:



Jumper Wires - Jumper wires are wires that are used to make connections on a breadboard. They have stiff ends that are easy to push into the breadboard holes. There are several types of jumper wires as per requirement. We will need all three types:



Resistors - A resistor is an electrical component that limits electrical current in an electronic circuit. Resistors can also be used to provide a specific voltage for an active device such as a transistor. For example, you have got an 2V LED and 3V battery; in this case you can't use LED as 3V current will destroy the LED. In this case if we use an resistor to limit the 3V current to less than equal to 2V, we can make a useful circuit.



It is important to calculate and use the correct resistor when building circuits. The color coding on a resistor reflect the resistance measure. More info on how to calculate resistor values can be found here.


LED -  LEDs (or Light Emitting Diodes) are like mini bulbs. It convert electrical energy into light energy. It is important to keep in mind that LEDs are polarised, which means you need to make sure you power it correctly or you will damage it. In a regular LED you will have a cathode and an anode terminal which represent the negative and positive sides respectively. On regular LED, you will find One Leg Shorter than the other. The short leg of the LED is called a cathode(-) and will connect to ground. The long leg of the LED is an anode(+) and will connect to power.





Push Switch - A push switch allows electricity to flow between its two contacts when held in. When the button is released, the circuit is broken. This type of switch is also known as a Normally Open (NO) Switch. (Examples: doorbell, individual keys on a keyboard). In circuits, we will be using Four leg push switch, which has the following functionality:


(Push Switch)


(Push Switch Connection)





(The circuit between both red dots will be complete when we push the switch down)


GPIO Pin's - One powerful feature of the Raspberry Pi is the row of GPIO (general purpose input/output) pins along the edge of the board.



The pins allow us to interact with different components and receive and send information to them.  At the simplest level, you can think of them as switches that you can turn on or off (input) or that the Pi can turn on or off (output). We will control different hardware with the use of these GPIO Pins.


There are 40 pins on the Raspberry Pi 3 and you can see they have different functions. Some pins provide power, some are ground and others will be used for receiving or sending values to our circuit’s components.




As shown in above figure, there are 40output pins for the PI. But when you look at the second figure, you can see not all 40 pin out can be programmed to our use. These are only 26 GPIO pins which can be programmed. These pins go from GPIO2 to GPIO27.

These 26 GPIO pins can be programmed as per need. Some of these pins also perform some special functions, we will discuss about that later. 

Now, we will move ahead with next tutorial, to understand the use of these hardware.

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