Scala/Akka library for serial communication

I like Scala and Akka a lot and am still doing some projects using an Arduino. Akka has a nice new interface for actor based interfacing (see Akka I/O) so I decided to write a little library that bridges the good old RXTX serial port library to it.

It was a rather easy exercise, it only took around 220 lines of code most of which are message definitions. RXTX is still nasty (esp. with regarding the handling of the native libraries), but at least my actor hides to ugly parts.
See my the rxtx-akka-io project on my github profile for the source code and some examples.

Short usage example (inside an akka actor):

override def preStart = IO(Serial) ! Open(port, 9600) 
override def receive = {
  case Opened(operator, _) =>
    println("Connected to port")
    context become open(operator)
}

The operator actor then accepts messages like Write(ByteString) and Close and starts sending Received(ByteArray) messages to the actor that started it.
Failure handling is easy, if something happens the operator actor will crash and leave it to it's parent (the actor that executes the code printed above) to restart it or handle it otherwise.

Happy Hacking!

Setup Arduino with Eclipse

While I think the Arduino IDE is great to play around with an AVR microcontroller it reaches its limits when used with bigger projects. They often need a better source code organisation, esp. if one's using C++ classes. Because of that I mostly switch to an Eclipse based development environment after an initial kickoff phase.

The setup of the eclipse based development environment for Arduino is a bit of a challenge. Following my setup procedure, based upon Robert Carlsen's Blog on a Mac OS X Snow Leopard and a Boardiuno:

• install XCode if not already done (else make will fail)
• install Cross Pack for AVR development
• install Arduino IDE
• Download and install Eclipse for C/C++ developers
• Install the AVR-Eclipse Plugin to Eclipse
• Help -> Install new software
• http://www.eclipse.org/downloads/ is the update site
• restart eclipse
• check the paths in Eclipse preferences / AVR / Paths
• should point to the cross pack
• Atmel Part Description Files is not needed
• add a AVRDude config (Eclipse preferences / AVR / AVRDude -> Add)
• Name: Boarduino
• Programmer Hardware: STK500 Version 1.x
• Baudrate: 57600
• Set port (find the port by 'ls /dev/cu.*', i.e. /dev/cu.usbserial-FTELSJ9T)

• create a new CPP project (or checkout my template)
• New C++ Project
• AVR Cross Target Application
• don't press finish, but next
• select hardware (ATMega 328P and 16 Mhz (16000000) for Boarduino)
• finish
• Open the properties of the newly created project
• AVR / AVRDude: Select the programmer ("Boarduino")
• under C/C++ Build/Settings (for both targets, Debug and Release)
• under "Additional Tools in Toolchain" check only:
• Generate HEX file for flash
• Print Size
• AVRDude (optional, directly uploads after compilation)
• under AVR compiler
• change command from "avr-gcc" to "avr-g++"
• Directories: add "/Applications/Arduino.app/Contents/Resources/Java/hardware/arduino/cores/arduino"
• Debugging: no debugging info
• Optimization: size (-Os)
• under AVR C++ compiler
• change command from "avr-gcc" to "avr-g++"
• Directories: add "/Applications/Arduino.app/Contents/Resources/Java/hardware/arduino/cores/arduino"
• Debugging: no debugging info
• Optimization: size (-Os)
• under AVR C++ Linker
• Add Library
• Name: core
• Add Library Path
• Path: ${workspace_loc:/Blink/lib}   (if the project name is "Blink")
• Open Arduino IDE and an example project
• set your Arduino (in Tools/Board)
• Click Verify/Compile in the toolbar while pressing shift
• Extract the folder name from the log-panel (beginning with /var/folders/....)
• copy the core.a from the folder into <eclipse-project>/lib/libcore.a
• Compile the project in Eclipse

Notes:

you might have to define 

    extern "C" void __cxa_pure_virtual(void);

    void __cxa_pure_virtual(void) {}

in your projects main.

And also:

    #undef int

    #undef abs

    #undef double

    #undef float

    #undef round

if you get compile errors in math.h and several other system-files.

Versions used:

• Eclipse 20100218-1602 (3.5 SR2)
• AVR Eclipse 3.2.1
• Arduino IDE 0018
• CrossPack AVR 20100115

Good luck.