Arduino UNO sending Temperature and Humidity data from DHT11 sensor to Raspberry pi 2(running windows iot core) through I2c

Question

I have made Arduino UNO as a slave and Raspberry Pi 2 as a master. The code running on Arduino UNO is as follows :

#include "DHT.h"
#include<Wire.h>
#define DHTPIN 4    // what digital pin we're connected to
#define DHTTYPE DHT11   // DHT 11
#define SLAVE_ADDRESS 0x29

DHT dht(DHTPIN, DHTTYPE);
int t;

void setup() {

  Serial.begin(9600); //setting baud rate for communication
  Wire.begin(SLAVE_ADDRESS); //assigning slave with i2c at defined slave address
  Wire.onRequest(sendData); //Event for sending the data through i2c
  dht.begin();
}

void loop() {

    float h = dht.readHumidity();
// Read temperature as Celsius (the default)
   t = dht.readTemperature();
  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t) || isnan(f)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }
  Serial.print("Humidity: ");
  Serial.print(h);
  Serial.print(" %\t");
  Serial.print("Temperature: ");
  Serial.print(t);
  Serial.print(" *C ");
  Serial.print("\n");
  Wire.onRequest(sendData); // asked to send the data 
  delay(1000);
}

void sendData(){
  Wire.write(t);
  Serial.print("in send data:"+t);
  }

The Raspberry Pi 2 code is written in c#. It is as follows :

using System;
using Windows.UI.Xaml.Controls;
using Windows.Devices.Enumeration;
using Windows.Devices.I2c;
using System.Diagnostics;
using System.Threading;

namespace App2
{
    public sealed partial class MainPage : Page
    {

    private I2cDevice Device;
    private Timer periodicTimer;

    public MainPage()
    {
        this.InitializeComponent();
        initcomunica();
    }

    private async void initcomunica()
    {

        var settings = new I2cConnectionSettings(0x29); // Arduino address
        Debug.WriteLine(settings);
        settings.BusSpeed = I2cBusSpeed.StandardMode;
        Debug.WriteLine(settings.BusSpeed);
        string aqs = I2cDevice.GetDeviceSelector("I2C1");
        Debug.WriteLine(aqs);

        var dis = await DeviceInformation.FindAllAsync(aqs);
        Debug.WriteLine(dis);
        Debug.WriteLine(dis[0].Id);
        Device = await I2cDevice.FromIdAsync(dis[0].Id,settings );
periodicTimer = new Timer(this.TimerCallback, null, 0, 1000); // Create a timmer
    }

    private void TimerCallback(object state)
    {
        byte[] RegAddrBuf = new byte[] { 0x08 };
        byte[] ReadBuf = new byte[5];
        try
        {
            Device.Read(ReadBuf); // read the data
            Debug.WriteLine(ReadBuf);

        }
        catch (Exception f)
        {
            Debug.WriteLine("error in reading from buffer"+f.Message);
        }
// Converte  Byte to CharArray
char[] cArray = System.Text.Encoding.UTF8.GetString(ReadBuf, 0,5).ToCharArray(); 

            String c = new String(cArray);
            Debug.WriteLine(c);

        }

    }
}

Connections done between Raspberry Pi 2 and Arduino UNO :

1. Analog pin of Arduino UNO (A4-SDA) connected to pin 5(SCL) of Raspberry Pi 2
2. Analog pin of Arduino UNO (A5-SCL) connected to pin 3(SDA) of Raspberry Pi 2

3. Used a voltage divider circuit with resistances 1K ohm and 2k ohm to give 3.3V to Pi instead of 5V.

4. DHT11 sensor connections with Arduino UNO.

Problem : I have deployed Universal windows app from Visual Studio on Pi code written in c# but I am getting an Exception in the code. The exception and error is as follows :

Exception thrown: 'System.Runtime.InteropServices.COMException' in mscorlib.ni.dll

WinRT information: Failed to apply connection settings to the device.

Additional information: A device attached to the system is not functioning.

Requirement : I have searched on Internet everything regarding this exception but didn't found any solution and Raspberry Pi 2 is unable to communicate with Arduino UNO.Don't know whether it is problem from Arduino side or Raspberry Pi side.

Please help me solve this problem.

Answer 1

It seems Your lines are wrong. Usually SCL pin connects to SCL and SDA connects to SDA. It's not reversed like on UART.