Introduction: Plant Humidity Monitor

Picture of Plant Humidity Monitor

In this article,we are going to talk about how to use micro:bit with buzzer, OLED and moisture sensor to build a case of plant detection device.

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Step 1: Goals

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1. Get to know the buzzer, OLED and moisture sensor.

2. Make something with a moisture sensor.

Step 2: Materials:

2X Female-Female Jumper Wires

1X Buzzer

1X Moisture Sensor


1 x BBC Micro:bit

1 x Micro USB Cable

1 x Breakout Board

Note: You can plug components in any sequence.

Step 3:

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In this project, we are going to create a plant monitoring which the buzzer will sound when there is not enough water.

A message will always be displaying on the OLED, showing the moisture level Firstly, plug in the OLED . You are able to plug it into any of the three rows.

Note: You can use any jumper wire colour.
Connect 2 Female-Female jumper wires to the Buzzer. The longer pin on the Buzzer will connect to the yellow pin on the breakout board, while the shorter one connects to the black pin. Plug the other end of the jumper wires to Pin0.

Step 4: Plug Moisture Sensor

Picture of Plug Moisture Sensor

For the next components, make sure the colour of the wire follows the coloured pins on the break out board.

Plug in the moisture sensor to Pin 1.

Step 5: Programming With Block Method.

Picture of Programming With Block Method.

Click Makecode to start programming and see more code sections.

We’ll add a package of code to be able to use our kit components. Look at the bottom of the Code Drawer for “Add Package” and click it.

Step 6: Click Thinkercademy

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Click on Tinkercademy inside the Code Drawer to find our custom blocks for the various components in your kit.

After that, use blocks under the Tinkercademy section to initialize the OLED

Since there are only two conditions, we need only one “else-if” statement.Micro:bit reads values from moisture sensor continuously. When the moisture sensor value is less than 50, this indicates that there is not enough water in the pot. As a result, the buzzer will sound and a message “Water your plant” will be displayed on OLED. Else if the moisture sensor value is larger than 50, the buzzer will be in silence and a message “Your plant is in good condition” will be displayed on OLED.

Step 7: Completed

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Finally! You have created a device to monitor your plant! Now, let’s try it!

Step 8: Let's Have a Try!

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Find a green plant and plug moisture sensor panel into the soil and watch. When there is not enough water, the buzzer will alarm to tell you "it's time to water your plant!". And when the plant has enough water, then the OLED panel will show you water is enough and no need to water the plant.

Isn't it very interesting?

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