Author: Lieven

Garmin simple text convertor script

I needed to test some XBee long-range radios. Hmm, how can we make this test useful and fun at the same time? Well, let’s put one end of the radio in the lab connected to a computer, and wander around with the other radio while transmitting the current position obtained from a GPS.

Using the XBee evaluation kit, my (t)rusty eTrex GPS, a 12V battery and some cables, the hardware was quickly in place. Now, what to transmit over the link? Full NMEA? Hmm, maybe this is a bit overkill. Sending the position once a second ought to be enough. But then I need a microcontroller between the GPS and the radio to reformat the NMEA into simple position beacons. There has to be an easier way…

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Deeg voor een echte pizzabodem

Ik ben al een tijdje op zoek naar het recept voor een ‘echte’ pizzabodem. Dus niet zo’n deeg dat eindigt al een broodachtige dikke laag onder je pizzabeleg, maar wel een elastisch en soepel deeg dat je kan uitrekken (of zoals de ‘echte’ met enkele zwaaien in de lucht in de juiste vorm brengt) en waarmee je een overheerlijke, Italiaanse pizza maakt met een dunne en knasperige bodem.

Hetvolgende recept vind ik tot nu toe het beste… De truuk zit hem in voldoende olijfolie te gebruiken, meer water toe te voegen dan je voor brooddeeg zou doen, en het deeg een nachtje te laten rusten vooraleer je het afbakt.
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xPL enabled utility meter monitor

When built our house, we took measures to ensure that we would consume little energy to keep our place to live warm and cosy. For this, we added extra insulation, we kept the number of air leaks as small as possible, and added a ventilation system that recycles the energy from the extracted air into the fresh air that is brought into our home.
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UPS power consumption

Recently I migrated my home server (a Linksys NSLU2 a.k.a. ‘Slug’) to a more powerful device (Mac Mini). The Mini has more capabilities and hence will run more services. Time to invest in a UPS that will keep the computer running when the electricity grid goes down.

Since the power consumption of my home server is a major concern to me, I’m also interested in the extra power consumption generated by the UPS.

I was able to measure the power consumption of a MGE Ellipse 750. Power was measured with a Voltcraft Energy Check 3000 and the test load was a normal PC (note: not the Mac Mini!).

The result was: the setup consumes 76 Watt without UPS and 80.5 Watt with the UPS. Note that the batteries of the UPS were fully loaded when the measurement was done.

Setting the execute bit in SVN

When committing files to an SVN repository, it happens that I forget to set the proper ‘execute’ permission.

This results in problems when checking out a fresh working copy, as it seems that SVN does not take up a ‘chmod u+x’ on a file as a change when a commit is performed.

This is easily fixed: just do

$ svn propset svn:executable ON somescript

And then commit.

Blowerdoor test

Een blowerdoor test wordt uitgevoerd om te bepalen hoe goed de woning luchtdicht is. De test geeft eigenlijk een soort ‘resultaat’ voor alle inspanningen die er gebeurd zijn om te voorkomen dat warme binnenlucht ongecontroleerd door kieren, spleten of gaten in de damprem naar buiten kan lekken.

Tegelijk worden bij de test ook de resterende lekken opgespoord.

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Self-powered wireless ambient light sensor

Since some time, the window blinds in our home are automatically controlled. When the sun rises they go up, at sunset they are closed.

To determine the correct time for the blind commands, I’ve written a mix of Perl scripts. There exists a handy Perl module to calculate sunrise/sunset based on the date and your location on earth. After some fiddling with the parameters, I have a setup that works rather good. However, the Perl module does not take into account the weather. On bright and cloudless days, the blinds can stay open a bit longer. When we’re on the other hand experiencing our typical North Sea autumn weather, they can safely be closed a bit earlier.

Enter some electronics 😉

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