The_Official_Raspberry_Pi_-_Beginner’s_Book_Vol1,_2018 (1)

124 THE OFFICIAL RASPBERRY PI BEGINNER'S GUIDE

A piezoelectric buzzer, usually just called a buzzer

or a sounder, is another output device. Whereas an

LED produces light, though, a buzzer produces a

noise – a buzzing noise, in fact. Inside the buzzer’s

plastic housing are a pair of metal plates; when active,

these plates vibrate against each other to produce the

buzzing sound. There are two types of buzzer: active

buzzers and passive buzzers. Make sure to get an

active buzzer, as these are the simplest to use.

Other common electrical components include motors, which need a special control board

before they can be connected to the Pi, infrared sensors which detect movement, temperature

and humidity sensors which can be used to predict the weather, and light-dependent resistors

(LDRs) – input devices which operate like a reverse LED by detecting light.

Sellers all over the world provide components for physical computing with the Raspberry Pi,

either as individual parts or in kits which provide everything you need to get started. Some of

the most popular retailers are:

n RS Components – uk.rs-online.com

n CPC – cpc.farnell.com

n Pimoroni – pimoroni.com

n Pi Hut – thepihut.com

n ModMyPi – modmypi.com

n PiSupply – uk.pi-supply.com

n Adafruit – adafruit.com

To complete the projects in this chapter, you should have at least:

n 3 × LEDs: red, green, and yellow or amber

n 2 × push-button switches

n 1 × active buzzer

n Male-to-female (M2F) and female-to-female (F2F) jumper wires

n Optionally, a breadboard and male-to-male (M2M) jumper wires