[作品提交] 【Follow me第二季第2期】开发板读取 SHT40 数据并上传至 Home Assistant

lijinlei 2024-9-26 20:13 楼主

# 【Follow me第二季第2期】开发板读取 SHT40 数据并上传至 Home Assistant

本章节的任务是开发板读取SHT40传感器数据并通过MQTT协议上传至EMQX服务器并在 HA 显示数据曲线

## 一、简介

### 1. HA 配置文件

`configuration.yaml`

通过配置该文件对 HA 指定任务，HA 则根据该文件调用组件并实现目标。

该文件的设定修改步骤如下：

1. [设置文件访问权限](https://www.home-assistant.io/docs/configuration/#to-set-up-access-to-the-files-and-prepare-an-editor) 
2. [找到 config 目录](https://www.home-assistant.io/docs/configuration/#to-find-the-configuration-directory) 
3. 编辑 `configuration.yaml`
4. 保存更改并[重新加载配置](https://www.home-assistant.io/docs/configuration/#reloading-the-configuration-to-apply-changes)以应用更改

详见：[Configuration.yaml - Home Assistant (home-assistant.io)](https://www.home-assistant.io/docs/configuration/) .

### 2. MQTT JSON

[JSON](https://www.json.org/json-zh.html), ( JavaScript Object Notation ), 是一种轻量级数据交换格式，如下

```json
{
  "some_arbitrary_key_name": "value"
}
```

详见：[MQTT JSON - Home Assistant (home-assistant.io)](https://www.home-assistant.io/integrations/mqtt_json/) .

## 二、方案

### 1. 流程

将前面介绍的 SHT40 温湿度传感器的串口输出相关代码与开发板通过 MQTT 协议连接至 Home Assistant 平台的代码相结合，具体流程如下

1. 开发板读取 SHT40 传感器采集的环境温湿度数据

2. 数据通过 MQTT 协议上传至 EMQX 服务器

3. HA 平台订阅主题、读取数据并将其转化至可视化面板显示出来，并实现历史曲线的观测和记录。

### 2. 代码

```
#include <ArduinoMqttClient.h>
#if defined(ARDUINO_SAMD_MKRWIFI1010) || defined(ARDUINO_SAMD_NANO_33_IOT) || defined(ARDUINO_AVR_UNO_WIFI_REV2)
  #include <WiFiNINA.h>
#elif defined(ARDUINO_SAMD_MKR1000)
  #include <WiFi101.h>
#elif defined(ARDUINO_ARCH_ESP8266)
  #include <ESP8266WiFi.h>
#elif defined(ARDUINO_PORTENTA_H7_M7) || defined(ARDUINO_NICLA_VISION) || defined(ARDUINO_ARCH_ESP32) || defined(ARDUINO_GIGA) || defined(ARDUINO_OPTA)
  #include <WiFi.h>
#elif defined(ARDUINO_PORTENTA_C33)
  #include <WiFiC3.h>
#elif defined(ARDUINO_UNOR4_WIFI)
  #include <WiFiS3.h>
#endif

#include "Adafruit_SHT4x.h"
#include "arduino_secrets.h"

//please enter your sensitive data in the Secret tab/arduino_secrets.h
char ssid[] = SECRET_SSID;    // your network SSID (name)
char pass[] = SECRET_PASS;    // your network password (use for WPA, or use as key for WEP)

// To connect with SSL/TLS:
// 1) Change WiFiClient to WiFiSSLClient.
// 2) Change port value from 1883 to 8883.
// 3) Change broker value to a server with a known SSL/TLS root certificate 
//    flashed in the WiFi module.

WiFiClient wifiClient;
MqttClient mqttClient(wifiClient);

const char broker[] = "49.52.23.140"; // IP address
int        port     = 1883; // port
const char topic[]  = "UNOR4/Send"; // MQTT topic

const long interval = 1000;
unsigned long previousMillis = 0;

int count = 0;
Adafruit_SHT4x sht4 = Adafruit_SHT4x();
float temperature_date,humidity_date;
sensors_event_t humidity, temp;
static TwoWire& SHT_I2C_INTERFACE = Wire1; // Wire1 is the QWIIC port of Uno R4 board

void setup() {
  //Initialize serial and wait for port to open:
  Serial.begin(115200);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

Serial.println("SHT40 test");
  if (! sht4.begin(&SHT_I2C_INTERFACE)) {
    Serial.println("Couldn't find SHT40");
    while (1) delay(1);
  }

Serial.println("Found SHT40 sensor");
  Serial.print("Serial number 0x");
  Serial.println(sht4.readSerial(), HEX);

// You can have 3 different precisions, higher precision takes longer
  sht4.setPrecision(SHT4X_HIGH_PRECISION);
  switch (sht4.getPrecision()) {
     case SHT4X_HIGH_PRECISION: 
       Serial.println("High precision");
       break;
     case SHT4X_MED_PRECISION: 
       Serial.println("Med precision");
       break;
     case SHT4X_LOW_PRECISION: 
       Serial.println("Low precision");
       break;
  }

// You can have 6 different heater settings
  // higher heat and longer times uses more power
  // and reads will take longer too!
  sht4.setHeater(SHT4X_NO_HEATER);
  switch (sht4.getHeater()) {
     case SHT4X_NO_HEATER: 
       Serial.println("No heater");
       break;
     case SHT4X_HIGH_HEATER_1S: 
       Serial.println("High heat for 1 second");
       break;
     case SHT4X_HIGH_HEATER_100MS: 
       Serial.println("High heat for 0.1 second");
       break;
     case SHT4X_MED_HEATER_1S: 
       Serial.println("Medium heat for 1 second");
       break;
     case SHT4X_MED_HEATER_100MS: 
       Serial.println("Medium heat for 0.1 second");
       break;
     case SHT4X_LOW_HEATER_1S: 
       Serial.println("Low heat for 1 second");
       break;
     case SHT4X_LOW_HEATER_100MS: 
       Serial.println("Low heat for 0.1 second");
       break;
  }

// attempt to connect to WiFi network:
  Serial.print("Attempting to connect to WPA SSID: ");
  Serial.println(ssid);
  while (WiFi.begin(ssid, pass) != WL_CONNECTED) {
    // failed, retry
    Serial.print(".");
    delay(5000);
  }

Serial.println("You're connected to the network");
  Serial.println();
  Serial.println(WiFi.localIP());

// You can provide a unique client ID, if not set the library uses Arduino-millis()
  // Each client must have a unique client ID
  // mqttClient.setId("clientId");

// You can provide a username and password for authentication
   mqttClient.setUsernamePassword("UNOR4", "123456");

Serial.print("Attempting to connect to the MQTT broker: ");
  Serial.println(broker);

if (!mqttClient.connect(broker, port)) {
    Serial.print("MQTT connection failed! Error code = ");
    Serial.println(mqttClient.connectError());

while (1);
  }

Serial.println("You're connected to the MQTT broker!");
  Serial.println();
}

void loop() {
  // call poll() regularly to allow the library to send MQTT keep alives which
  // avoids being disconnected by the broker
  mqttClient.poll();

// to avoid having delays in loop, we'll use the strategy from BlinkWithoutDelay
  // see: File -> Examples -> 02.Digital -> BlinkWithoutDelay for more info
  unsigned long currentMillis = millis();
  
  if (currentMillis - previousMillis >= interval) {
    // save the last time a message was sent
    previousMillis = currentMillis;

Serial.print("Sending message to topic: ");
    Serial.println(topic);
    // Serial.print("temperature:");
    // Serial.println(temperature_date);
    // Serial.print("humidity: ");
    // Serial.println(humidity_date);
    uint32_t timestamp = millis();
    sht4.getEvent(&humidity, &temp);// populate temp and humidity objects with fresh data
    timestamp = millis() - timestamp;

Serial.print("Temperature: "); Serial.print(temp.temperature); Serial.println(" degrees C");
    Serial.print("Humidity: "); Serial.print(humidity.relative_humidity); Serial.println("% rH");

Serial.print("Read duration (ms): ");
    Serial.println(timestamp);
    temperature_date=temp.temperature;
    humidity_date=humidity.relative_humidity;

// send message, the Print interface can be used to set the message contents
    mqttClient.beginMessage(topic);
    mqttClient.println("{");
    mqttClient.print("   \"temperature\":");
    mqttClient.print(temperature_date);
    mqttClient.println(",");
    mqttClient.print("   \"humidity\":");
    mqttClient.println(humidity_date);
    mqttClient.print("}");
    mqttClient.endMessage();

Serial.println();

count+=0.01;
  }
}
```

串口输出情况如下

MQTTX 客户端输出效果如下

下面考虑如何将该数据显示在 HA 面板。

### 3. MQTT 配置信息

前面测试程序中发送的是温度和湿度数据，因此需要在 Home Assistant 中增加传感器信息。

```json
# Example configuration.yaml entry
mqtt:
  sensor:
    - name: "Temperature"
      state_topic: "UNOR4/Send"
      suggested_display_precision: 1
      unit_of_measurement: "°C"
      value_template: "{{ value_json.temperature }}"
    - name: "Humidity"
      state_topic: "UNOR4/Send"
      unit_of_measurement: "%"
      value_template: "{{ value_json.humidity }}"
```

参考： [MQTT Sensor - Home Assistant (home-assistant.io)](https://www.home-assistant.io/integrations/sensor.mqtt/) .

注意这里 HA 官方说明文档中给出的例程，其中开发板上传的数据格式为 JSON 格式，我们的输出结果与例程的格式一致，因此将例程中对应的 HA 配置代码添加至 `configuration.yaml` 文件并修改订阅主题即可。

### 4. 效果

在 `设置` 中重新加载 `YAML 配置` 即可显示传感器面板及温湿度数据，如下图所示

点击 `Humidity` 和 `Temperature` 即可显示历史曲线，鼠标指针可以显示每个时刻的具体数据

此外，还可以将数据联系至仪表表盘，实现 UI 界面优化，使产品设计更加人性化。

#### 视频展示
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