5.1 If else

Usually we use conditional judgment to complete the most basic reality interaction projects. Here, we build a door detection system with reed switch and LED to show this logic.

Fix the magnet on one side of the door and the reed switch (with circuit) on the other side of the door. When the door is closed, the magnet is close to the reed switch, which will turn it on.

Required Components

In this project, we need the following components.

It’s definitely convenient to buy a whole kit, here’s the link:

Name

ITEMS IN THIS KIT

LINK

3 in 1 Starter Kit

380+

3 in 1 Starter Kit

You can also buy them separately from the links below.

COMPONENT INTRODUCTION

PURCHASE LINK

SunFounder R3 Board

BUY

Breadboard

BUY

Jumper Wires

BUY

Resistor

BUY

LED

BUY

Reed Switch

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Schematic

../_images/circuit_8.1_ifelse.png

Wiring

../_images/if_else_bb.jpg

Code

Note

  • Open the 5.1.if_else.ino file under the path of 3in1-kit\basic_project\5.1.if_else.

  • Or copy this code into Arduino IDE.

  • Or upload the code through the Arduino Web Editor.

After the code is uploaded successfully, if you do not close the door, the LED will light up, prompting you to close the door.

By the way, if we need the opposite effect (lighting up the LED when the door is closed), we just need to modify the condition in the if.

  • if else

    The if else allows greater control over the flow of code than the basic if statement, by allowing multiple tests to be grouped.