Category Archives: Uncategorized

Scala, Scala

It is a while I am following courses on coursera. It is really amazing.

Right now I am followin “Principles of reactive programming”. I have to say it is just fascinating !

Programming assignments are anything but easy. Needs a lot of time.

Idea of Future, Response and observables  are so natural. I have to do a comparison to the same facilities in Java and Python.

I really recommend the courses.

Expression Language Validation

We used juel as an expression language EL implementation in one our projects. The problem we had, was that we could not afford waiting for the expression to be checked at runtime. For example if you are accessing a pojo field, and that field does not exist, they you only know it in runtime.

To fix this, I created an extension and added a validate method. This method traverses the tree and checks all possible options to make sure the expression is valid with given objects.

I offered the new extention to the community, but they thought it is better to keep the Juel to minimum required to match the standard.

I am going  to publish as an extension to Juel in seperate branch. Maybe someone else also can make use of it. Not planned yet though.

Python Library for bluetooth

Just for its fun, I have started to build a remote control robot, using

– Mindstorm

– Raspberry pi

– Camera

– Joystick

– python

First step is to read joystic in python. I checked pygame.joystick and it works fine.

Sending values to NXT over Bluetooth is not that simple. There are not much on we. I checked jaraco.nxt . The source looks very sophisticated and a large range of commands are supported. For me it did not work for any reason.

Second attempt was “Roboter Platform“. A simple low library which works. Does not cover all commands but works find for what I want. The good part is it is very easy to see how things work and expand it.

Now I am able to send information in Message formats to NXT. The next step would be to control the movement of Robot with Joystick.

 

Experience with Asus WL-500g

This is my first technical post in my technical blog.

I have recently bought an  Asus WL-500g V2 premium. I selected it because of these unique features:

  • 32 MB RAM
  • 8 MB  Flash
  • 240 Mhz CPU
  • 2 USB ports
  • Good price

I bought it some 25 euros from ebay.

Till now, I have flashed it with openWRT, installed ntfs-3g and samb, so I can use it as a media server

 

 

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