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.

../../_images/case_02_01.png

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.

../../_images/case_02_03.png

Assembly Video#

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

Assembly Steps#

../../_images/case_step_02_01.png

../../_images/case_step_02_02.png

../../_images/case_step_02_03.png

../../_images/case_step_02_04.png

../../_images/case_step_02_05.png

../../_images/case_step_02_06.png

../../_images/case_step_02_07.png

../../_images/case_step_02_08.png

3.3. MakeCode Programming#

Step 1#

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

../../_images/case_01_10.png

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.

../../_images/case_01_11.png

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:#

../../_images/case_02_10.png

Reference#

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

You may also download it directly below:

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.

../../_images/case-gif-02.gif