7. case 05 Water Level Alarming


7.1. Goal

  • Make a water level alarming.

7.2. Materials

  • 1 x Smart home Kit]

  • 1 x tank

7.3. Background

What is water level alarming

  • We can’t live without water, but much water will cause flood. Water level alarming can detect water level, micro:bit will received signals when the water level over security line and control lift pump to pumping.

Water level alarming operation

  • When micro:bit received signal of soil moisture sensor,relay will drive and supply power to lift pump for pumping redundant water.


7.4. Practical operation

Preparing a tank and paste devices as below piture:


7.5. Hardware connect


While connecting the cables with the Relay, please use screwdrivers to loosen the screws on the Relay first to make sure the cables get connected properly.


7.6. Software


Edge Connector Data Sheet

7.7. Programming

Step 1

Go to MakeCode page, click Advanced in the code block and click on Extensions.


We need to add a new codebase for programming of smart home. Finding “Add Package” in the bottom of code block and click it. Then a message box will show up, search “smart home”, and download this new codebase.


Note:If there is a hint says some codebase will be deleted because of incompatibility. Don’t worry. You could go ahead as the hint or build a new item in item menu bar.

Step 2

Snap if statement into forever,set analog read pin P2 > 500, that’s say when P2 > 500, the water level is higher than security line.


Step 3

Set start melody “ba ding” repeating once as alarming voice, set digital write pin P1 to 1 as driving the pumping.


Step 4

Else,set digital write pin P1 to 0 as turning off the pump.



Make code:https://makecode.microbit.org/_9KqHhp1J45ho

You also could directly download program visit website as below:


7.8. Result

When the water level over security line,micro:bit will control lift pump to pumping.



Stop pumping:


7.9. Think

How to use micro:bit control water level in fish tank ?

7.10. Questions

7.11. More information