Monthly Archives: April 2013

Symfony2, Assetic, Twitter Bootstrap + Bootswatch

This is a quick’n’dirty guide for newcomers to symfony’s assetic and twitter bootstrap in conjunction with bootswatch. This is not a complete guide and reflects my own opinion only.

Quick terms:

  • Assetic is automated asset management and compilation, in this example it’s used to compile less files
  • less is used to compile a templateish CSS language into real CSS files your browser understands
  • Your advantages:
    • Easy color changes
    • One command to update your css
  • First, install nodejs. 
  • Configure bootstrap and jquery packages:


  • Add the following block to your config.yml and change the paths as explained in the comments.


  • Create a new build.less file and add the following stuff:

  •  Choose your favourite theme at and download both .less files per theme. Place them alongside in the same directory where you placed your build.less file.

Now you can run app/console assetic:dump to compile the less file into a css file, which you then can include using the usual twig fragment:

That’s it. If you’re getting any errors, I’m sorry: You need to find out yourself what’s going on. I’ve spend 3 hours to get the initial setup running. Guides I’ve followed or files I’ve looked at:

  • (I’m not using the bootstrap bundle, as I don’t currently see the need for it. This might change as soon as I’m using KnpPaginator, KnpMenu and symfony forms. I just left the bundle out because I had trouble getting it to work, the reason was that my nodejs setup was forked up).
  • The build scripts for bootswatch
  • The source for the Assetic Less filter (no, you can’t inject different less imports, hence the build.less encapsulation script above)


Autonomous WLAN Router Experiment: Part 1

I’ve been wanting to build an autonomous WLAN router for quite some time. That WLAN router should be powered by a solar cell and a battery. I have spoken about the TL-WR702N at RaumZeitLabor a while ago, and it is very small, draws 150mA max and is therefore suitable for such a project.

Some time has passed, and yesterday Doozer gave two Lead–acid batteries to me, rated 12V 5Ah each. So now I have to do this project!

I’ll use one battery for the project. I have made the following assumptions:

Ed: Average daily electricity production (kWh)
Em: Average monthly electricity production (kWh)

  • The router will permanently draw 150mA at 5V, or 0.75W (worst-case)
  • The solar charger circuit will have a power requirement of 15mA at 12V (0.075W)
  • The DC-DC converter I’ll be using has an efficiency of 80% (worst-case assumption, will probably be much higher)
  • To be on the safe side, all further calculations assume that our overall power usage is 2W
  • Overall yearly power: ~18kWh, 1.5kWh per month
  • Using the interactive photovoltanic calculator (linked below) I was able to calculate that a 20Wp cell is not sufficient from October till February.
  • As we assumed the worst-case scenario, and this is an experiment only, I decided to go with two 20W panels, where I’ll experiment with one panel, then two if it’s not sufficient.

I now have to buy the solar panels and the charge controller, which I’ll do in may.

Useful resources: