C#でIoTプログラミング on ESP32 #13 - SCD40

Co2センサー SCD40のサンプルプログラムです。

ハードウェア

・Freenove ESP32-S3-WROOM Board or Espressif ESP32-S3-DevKitC
・Adafruit SCD40

配線

導入パッケージ

・nanoFramework.Hardware.Esp32
・nanoFramework.System.Device.I2c
・nanoFramework.System.Buffers.Binary.BinaryPrimitives

プログラミング

Program.cs

using nanoFramework.Hardware.Esp32;
using System;
using System.Buffers.Binary;
using System.Device.I2c;
using System.Threading;

namespace ESP32S3_SCD40
{
    public class Program
    {
        private static SpanByte start => new byte[] { 0x21, 0xb1 };         //スタートコマンド
        private static SpanByte read => new byte[] { 0xec, 0x05 };          //リードコマンド
        private static I2cDevice device;

        public static void Main()
        {
            Configuration.SetPinFunction(8, DeviceFunction.I2C1_DATA);
            Configuration.SetPinFunction(9, DeviceFunction.I2C1_CLOCK);

            I2cConnectionSettings settings = new(1, 0x62, I2cBusSpeed.FastMode);
            device = I2cDevice.Create(settings);

            device.Write(start);
            Thread.Sleep(1000);

            device.Write(read);

            Thread.Sleep(50);

            Timer timer = new Timer(getData, null, 0, 10000);

            Thread.Sleep(Timeout.Infinite);
        }

        private static void getData(object state)
        {
            SpanByte buffer = new byte[9];

            device.Read(buffer);

            var co2 = BinaryPrimitives.ReadInt16BigEndian(buffer.Slice(0, 3));
            var tmp = -45 + 175 * (float)(BinaryPrimitives.ReadUInt16BigEndian(buffer.Slice(3, 3))) / 65536;
            var hum = 100 * (float)(BinaryPrimitives.ReadUInt16BigEndian(buffer.Slice(6, 3))) / 65536;

            Console.WriteLine($"Temp: {tmp.ToString("F")}, Hum: {hum.ToString("F")}, Co2: {co2}");
        }
    }
}