3. Case 02: Flower-watering Prompter

3.1. Introduction

Some plants can make people live healthier. For example, a pot of green dill in a room of 8-10 square meters is equivalent to an air purifier, which can effectively absorb harmful gases such as formaldehyde, benzene and trichloroethylene in the air. Thus, we can make a simple watering device to help us take care of plants.

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3.2. Quick Start

Materials Required

Nezha expansion board × 1

micro:bit × 1

LED-red × 1

LED-green × 1

Soil moisture sensor × 1

RJ11 wires × 3

Connection Diagram

Connect the green LED to J4, red LED to J3 and soil moisture sensor to J2 on the Nezha expansion board as the picture shows.

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Assembly Video

Video reference:https://youtu.be/YxEKEoDB6FQ

Assembly Steps

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3.3. MakeCode Programming

Step 1

Click “Advanced” in the MakeCode to see more choices.

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For programming, we need to add a package: click “Extensions” at the bottom of the MakeCode drawer and search with “PlanetX” in the dialogue box to download it.

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Notice: If you met a tip indicating that some codebases would be deleted due to incompatibility, you may continue as the tips say or create a new project in the menu.

Step 2

Code as below:

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Reference

Link：https://makecode.microbit.org/_2FgMYuLiUeE8

You may also download it directly below:

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Result

The red LED lights on for reminding of watering if the soil moisture sensors gets a low value from the earth, or the green LED lights on.

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