### 4.4 Project : Rain Detection System

**NOTE: Sprinkling water on sensors(except steam sensor) may cause a short circuit or modules to be out of work. If batteries get wet, even explosion may occur. Do be extra careful! For younger users, please operate with your parents. To guarantee security, please obey guidances and safety regulations.**

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In this project, we will create a rain detection system by a steam sensor. When rain is detected, ESP32 triggers various actions like sending message, activating sprinklers and turning on lights. Through this system, rainfall amount can be monitored, and water leakage can also be detected on roofs or in buildings.

Besides, it is easy to connect the steam sensor to ESP32 board, which forms a simple but effective rain detection system.

![img](../media/cout4.png)

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#### 4.4.1 Flow Diagram


![image-20230607180917475](../media/image-20230607180917475.png)

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#### 4.4.2 Steam Sensor


**Description:**

Steam sensor detects the presence of water, so it is usually used in rain detection. If the rain hits the conductive pad on the sensor, it will send a signal to the KidsBlock board.

![img](../media/cou41.png)

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**Schematic Diagram:**

![img](../media/couy41.png)

**Parameters:**

-  Voltage: 3~5V
-  Current: 1.5mA
-  Power: 7.5mW

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**Wiring Diagram:**

**Connect the steam sensor to io35.**

**Attention: Connect yellow to S(Signal), red to V(Power), and black to GND. Do not reverse them!**

![img](../media/couj41.png)

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**Test Code:**

-  Initialize the serial port.

![img](../media/st67.png)

-  Read the sensor value at pin io35 and print it per second.

![img](../media/st68.png)

Complete code:

![img](../media/st69.png)

**Test Result:**

Touch the detection area with a wet finger. The larger the area you touched is, the larger the value will be. You may open the serial monitor to observe the currently detected value (range: 0~4095).

![img](../media/st70.png)

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#### 4.4.3 Rain Detection System


**Description:**

When the steam sensor detects rain, it sends a signal to the board to trigger various actions, for instance, the buzzer alarms to remind that it is raining. This is especially useful for outdoor gardening and farming, enabling users to take necessary precautions to avoid over-watering.

Additionally, this system can be used to detect water leakage to prevent damage from water intrusion. Overall, the steam sensor is versatile and effective in various applications.

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**Wiring Diagram:**

**Connect the steam sensor to io35 and buzzer to io16.**

**Attention: Connect yellow to S(Signal), red to V(Power), and black to
GND. Do not reverse them!**

![img](../media/couj42.png)

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**Test Code:**

Code flow:

![img](../media/flo4.png)

Code:

-  Initialize the serial port, and define a variable **item** as the received sensor value.

![img](../media/st71.png)

-  Receive the sensor value and print it on the serial monitor.

![img](../media/st72.png)

-  The received value detected by the sensor is within 800 ~ 1999:

![img](../media/st73.png)

-  The received value detected by the sensor is within 2000 ~ 2999:

![img](../media/st74.png)

-  The received value detected by the sensor is greater than 3000:

![img](../media/st75.png)

-  At the end of code blocks, add a "**No Tone**" to turn off the buzzer.

![img](../media/st76.png)

Complete code:

![img](../media/st77.png)

**Test Result:**

The greater the detected value is, the loader the sound emitted by the buzzer will be.

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#### 4.4.4 FAQ


Q: Is the steam sensor waterproof?

A: The detection area can be exposed to water, but the wire junctions are not waterproof. During the experiment, please pay attention to the amount of water not to be too much to prevent short circuit.

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Q: Although a long time has elapsed since the sensor detected water, the buzzer keeps buzzing.

A: It keeps buzzing because there are still blots of water in the detection area. Please just clean it up.

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