CO2センサを使う④AdafruitのSCD-30ボードをArduino Nano RP2040 ConnectにつないでBLEペリフェラルに（3）

　SCD-30ボードはCO2以外に温度と湿度のデータも扱っています。前回のスケッチに、温度と湿度も扱えるようにしました。

●スケッチ

　DescriptorのUUIDはいずれも2901です。2901は、Characteristicの説明文字列（UTF-8）を追加します。


#include <ArduinoBLE.h>

#define SCD30_SERVICE_UUID   "F000AA30-0451-4000-B000-000000000000"
// BLE Service
BLEService Sensor_SCD30_Service(SCD30_SERVICE_UUID);

#define SCD30_C_Characteristic_UUID    "F000AA31-0451-4000-B000-000000000000"
#define SCD30_T_Characteristic_UUID    "F000AA32-0451-4000-B000-000000000000"
#define SCD30_H_Characteristic_UUID    "F000AA33-0451-4000-B000-000000000000"
// BLE  Characteristic
BLEFloatCharacteristic  SCD30_CO2_Characteristic(SCD30_C_Characteristic_UUID, BLERead | BLENotify);
BLEFloatCharacteristic  SCD30_Temperature_Characteristic(SCD30_T_Characteristic_UUID, BLERead | BLENotify);
BLEFloatCharacteristic  SCD30_Humidity_Characteristic(SCD30_H_Characteristic_UUID, BLERead | BLENotify);

#define SCD30_C_Descriptor_UUID    "2901"
#define SCD30_T_Descriptor_UUID    "2901"
#define SCD30_H_Descriptor_UUID    "2901"
// BLE  Descriptor
BLEDescriptor   SCD30_C_Descriptor(SCD30_C_Descriptor_UUID, "CO2;ppm IEEE-754 format");
BLEDescriptor   SCD30_T_Descriptor(SCD30_T_Descriptor_UUID, "Temperature;`C");
BLEDescriptor   SCD30_H_Descriptor(SCD30_H_Descriptor_UUID, "Humidity;%");

#include <Adafruit_SCD30.h>
Adafruit_SCD30  scd30;
float CO2 = 0, Temperature = 0, Humidity = 0;
 
void readSCD30() {
  if (scd30.dataReady()){
    if (!scd30.read()){ Serial.println("Error reading sensor data"); return; }
      CO2 = scd30.CO2; Temperature = scd30.temperature, Humidity = scd30.relative_humidity;
  }
}

#define localNAME  "RP2060_SCD30_float"
#define DeviceNAME "RP2060_CO2_BLE"
 
float oldValue = 0;  // last value 
float previousMillis = 0;  // last time value was checked, in ms
 
void setup() {
  Serial.begin(9600);    // initialize serial communication
  while (!Serial);
 
  // begin initialization
  if (!BLE.begin()) {
    Serial.println("starting BLE failed!");
    while (1);
  }
 
  if (!scd30.begin()) {
    Serial.println("Failed to find SCD30 chip");
    while (1) { delay(10); }
  }
  
  BLE.setLocalName(localNAME);
  BLE.setDeviceName(DeviceNAME);

  // add the service UUID
  BLE.setAdvertisedService(Sensor_SCD30_Service);

  // add characteristic
  Sensor_SCD30_Service.addCharacteristic(SCD30_CO2_Characteristic);
  Sensor_SCD30_Service.addCharacteristic(SCD30_Temperature_Characteristic);
  Sensor_SCD30_Service.addCharacteristic(SCD30_Humidity_Characteristic);
  
  // add descriptor
  SCD30_CO2_Characteristic.addDescriptor(SCD30_C_Descriptor);
  SCD30_Temperature_Characteristic.addDescriptor(SCD30_T_Descriptor);
  SCD30_Humidity_Characteristic.addDescriptor(SCD30_H_Descriptor);
    
  // Add service
  BLE.addService(Sensor_SCD30_Service);
 
  // set initial value for this characteristic
  SCD30_CO2_Characteristic.writeValue(0);
  SCD30_Temperature_Characteristic.writeValue(0);
  SCD30_Humidity_Characteristic.writeValue(0);
    
  // start advertising
  BLE.advertise();
  Serial.println("Bluetooth device active, waiting for connections...");
}
 
void loop() {
  // wait for a BLE central
  BLEDevice central = BLE.central();
 
  // if a central is connected to the peripheral:
  if (central) {
    delay(100);
    Serial.print("Connected to central: ");
    // print the central's BT address:
    Serial.println(central.address());
 
    // check  every 200ms. while the central is connected:
    while (central.connected()) {
      long currentMillis = millis();
      // if 200ms have passed, check value:
      if (currentMillis - previousMillis >= 200) {
        previousMillis = currentMillis;
        updateValue();
        delay(1000);
      }
    }
    // when the central disconnects
    Serial.print("Disconnected from central: ");
    Serial.println(central.address());
  }
}

void updateValue() {
  readSCD30();

  // if value has changed
  if (CO2 != oldValue) {

    Serial.println(String(CO2,2) + "ppm " + String(Temperature,1) + "`C " + String(Humidity,1) + "%");
    
    // update  characteristic
    SCD30_CO2_Characteristic.writeValue(CO2);
    SCD30_Temperature_Characteristic.writeValue(Temperature);
    SCD30_Humidity_Characteristic.writeValue(Humidity);
    oldValue = CO2; // save the level for next comparison
  }
}

　RSL10のモニタで観測しました。