HG, Raspberry Pi and Arduino (UART or I2C)

[tomasz2101]

Hi all
I'm new user and I want to connect Raspberry Pi (master) with Arduino (slave) over UART  or I2C. I don't know which method is better. With UART communication i need to connect them as in the picture 1.
With I2C it doesn't need level shifter if arduino works as slave but i don't know if there will be others I2C devices working on 5V (because rPi works on 3,3 V).

Raspberry should send and receive packages from arduino. In HG i want to set up few on/off switches, the rPi will sent info to arduino and it will turn it on or off and send info back to rPi.

Few days ago i wrote program for  two arduinos master/slave in I2C and i'm sending info over array.  Can anyone say if it will be helpful ?

Can anyone help me ?? Please

[bkenobi]

I tested using an Arduino with RPi around a year ago.  I was able to get some versions of the Arduino to connect to the RPi and even had HG communicating and able to upload code.  In my case, I was using the serial connection (UART).  I don't remember all the details of how to get things working at this point, but know it did work at least to some degree.

In the end, I opted to use an Arduino Uno with Ethernet shield to work independently and then communicate the collected date to HG via MQTT.  I used Mosquitto on the RPi as I was never able to get the HG MQTT broker to work.

If you would like details, please review the threads here as I posted all details from my work.  I'll try to find the specific thread and post a link.

EDIT: This is the thread
http://www.homegenie.it/forum/index.php?topic=835

[tomasz2101]

I'm trying to connect RPI to Arduino over I2C with very simply program in python (i would prefer C# but I don't know how to write it):

Code: [Select]

import smbus
import time
bus = smbus.SMBus(1)
address = 0x08

while True:
    data = ""
    for i in range(0, 5):
            data += chr(bus.read_byte(address));
    print data
    time.sleep(1);
And I' getting error in import smbus. I've installed sudo apt-get install python-smbus. Can anyone help me with it ?

[Gene]

try adding these lines before everything else:

Code: [Select]

import sys
sys.path.append("/usr/lib/python2.7/")
sys.path.append("/usr/lib/python2.7/dist-packages")
#sys.path.append("/usr/lib/python2.7/dist-packages/smbus")

not sure about the last one. Also read this:

http://www.homegenie.it/forum/index.php?topic=1062.msg6411#msg6411

Cheers,
g.

[Gene]

Btw, there's EdenV2 firmware source code for Arduino and the HG app (C#). This is an example of exchanging messages over SPI between RPi and Arduino.

https://sourceforge.net/projects/homegenie/files/testing/

g.

[tomasz2101]

I found that you posted this program for SPI communication:

Code: [Select]

var adcClock = ConnectorPin.P1Pin23.ToProcessor();
var adcMiso = ConnectorPin.P1Pin21.ToProcessor();
var adcMosi = ConnectorPin.P1Pin19.ToProcessor();
var adcCs = ConnectorPin.P1Pin22.ToProcessor();

var spiConnection = new Raspberry.IO.SerialPeripheralInterface.SpiConnection(adcClock, adcCs, adcMiso, adcMosi, 0 /*Endianness.LittleEndian*/);

using(spiConnection.SelectSlave())
{
 
  // Start bit
  spiConnection.Write(true);
 
  // Channel is single-ended
  spiConnection.Write(true);
 
  // Channel Id
  spiConnection.Write((byte)2, 3);

  // Let one clock to sample
  spiConnection.Synchronize();
 
  while (true)
  {
    // Read 8 bits
    for (int i = 0; i < 8; i++)
    {
      var data = spiConnection.Read(8);
      Console.Write( data.ToString("X2") + " "); 
    }
    Console.WriteLine("");
  }
}
But it gives me those errors:
Line 9, Column 21 (Code):
    The best overloaded method match for `Raspberry.IO.SerialPeripheralInterface.SpiConnection.SpiConnection(Raspberry.IO.IOutputBinaryPin, Raspberry.IO.IOutputBinaryPin, Raspberry.IO.IInputBinaryPin, Raspberry.IO.IOutputBinaryPin, Raspberry.IO.SerialPeripheralInterface.Endianness)' has some invalid arguments

    /usr/local/bin/homegenie/Raspberry.IO.SerialPeripheralInterface.dll (Location of the symbol related to previous error)

Line 9, Column 78 (Code):
    Argument `#1' cannot convert `Raspberry.IO.GeneralPurpose.ProcessorPin' expression to type `Raspberry.IO.IOutputBinaryPin'

[Gene]

With time the SDK changed a little bit.

This is the code that should work:

Code: [Select]

var spiClock = ConnectorPin.P1Pin23.ToProcessor();
var spiMiso = ConnectorPin.P1Pin21.ToProcessor();
var spiMosi = ConnectorPin.P1Pin19.ToProcessor();
var spiCs = ConnectorPin.P1Pin24.ToProcessor();

var driver = GpioConnectionSettings.DefaultDriver;
driver.Allocate(spiClock, PinDirection.Output);
driver.Allocate(spiCs, PinDirection.Output);
driver.Allocate(spiMosi, PinDirection.Output);
driver.Allocate(spiMiso, PinDirection.Input);

var spiConnection = new SpiConnection(
  driver.Out(spiClock),
  driver.Out(spiCs),
  driver.In(spiMiso),
  driver.Out(spiMosi),
  Endianness.LittleEndian
);

// Release allocated resource when program is stopping
When.ProgramStopping(()=>{
  try
  {
    ((IDisposable)spiConnection).Dispose();
  } catch (Exception e) { Program.Notify("SPI Error", e.Message); }
  ((IDisposable)driver).Dispose();
  return true;
});

For your reference you can look at a bunch of example programs in the Configure->Programs->RaspberryPi section.
Also see the RaspberrySharp-IO examples and source code that is located here:
https://github.com/raspberry-sharp/raspberry-sharp-io/tree/master/Tests

Cheers,
g.

[tomasz2101]

Ok it doesn't give me errors but i think i need to add to your code the last part of the previous code yes ? it will look like this :

Code: [Select]

var spiClock = ConnectorPin.P1Pin23.ToProcessor();
var spiMiso = ConnectorPin.P1Pin21.ToProcessor();
var spiMosi = ConnectorPin.P1Pin19.ToProcessor();
var spiCs = ConnectorPin.P1Pin24.ToProcessor();

var driver = GpioConnectionSettings.DefaultDriver;
driver.Allocate(spiClock, PinDirection.Output);
driver.Allocate(spiCs, PinDirection.Output);
driver.Allocate(spiMosi, PinDirection.Output);
driver.Allocate(spiMiso, PinDirection.Input);

var spiConnection = new SpiConnection(
  driver.Out(spiClock),
  driver.Out(spiCs),
  driver.In(spiMiso),
  driver.Out(spiMosi),
  Endianness.LittleEndian
);

// Release allocated resource when program is stopping
When.ProgramStopping(()=>{
  try
  {
    ((IDisposable)spiConnection).Dispose();
  } catch (Exception e) { Program.Notify("SPI Error", e.Message); }
  ((IDisposable)driver).Dispose();
  return true;
});

using(spiConnection.SelectSlave())
{
 
  // Start bit
  spiConnection.Write(true);
 
  // Channel is single-ended
  spiConnection.Write(true);
 
  // Channel Id
  spiConnection.Write((byte)2, 3);

  // Let one clock to sample
  spiConnection.Synchronize();
 
  while (true)
  {
    // Read 8 bits
    for (int i = 0; i < 8; i++)
    {
      var data = spiConnection.Read(8);
      Console.Write( data.ToString("X2") + " "); 
    }
    Console.WriteLine("");
  }
}

With function spiConnection.Read program want to receive data and print it with Console.Write  yes ??
Sry for stupid questions but everything is need for me here.