On the Use of Things
I have been carrying a lot of things around with me for as long as I can remember, which people now call "EDC", every day carry. There was no acronym back then, but as a teenager I already wore an…
Der Pfeil Blog
Richtungsweisendes vom Pfeil (“Pointers from Pfeil”): notes by Markus Pfeil from 2021 to 2025 on science and magic, self-experiments with solar charging and minimalism, and small making projects. The archive of the earlier blog at derpfeil.me, translated from German.
Science and Magic
A programme for everyone who likes to look at the world from two different perspectives, and to gain a more beautiful view of the world from it! I offer it sometimes as a workshop, sometimes as a…
Winter and Its Consequences
Today there is a short update on the two challenges and what winter has done to them. CyclingAfter Christmas I actually had to take a break, which is still going on. I rode my shorter route to…
The State of Solar Charging Before Advent
Now that I have kept up the solar charging challenge for several months, it is time for an update. In summer it was no problem to keep the power bank full: lots of hours of sunshine and the high…
Hexapawn Pocketmod
A minimalist variant of Martin Gardner's matchbox computer, which I made because the classic version with 24 matchboxes is very laborious to build. Hexapawn Pocketmod PDF The files are available…
Challenges and Freedom
I am in the middle of opening a few more challenges. So far I have been doing 16/8 intermittent fasting on 5 days a week; now I want to add one full fasting day. To buy fewer things and not be…
More Sun, and More Screen Time
Now that the sun has been out for a few days and I can even keep the phone supplied with the small gizmo, I see that I am also sitting in front of the screen 25% more per day again. So it shows…
And Then the Sun Came Out
Two decisive things have happened. Firstly, there is finally sun! That is the decisive point. The new 19 W Anker solar panel without a battery produces the finest little electrons! Lying flat on…
One Week Later … No More Advent
There seems to be no little light any more. (The four LEDs on the power bank work like the candles of an Advent wreath: one fewer for each quarter of charge lost.) My usage statistics point…
After the First Weekend
So it turns out that a decisive factor in the whole thing is good placement of the solar panels over the course of the day. Over the weekend they only lay in front of the window on the table and…
Day 2: Efficiency
According to [1], the battery in my iPhone XS has a capacity of 2658 mAh. That means it can deliver 2658 mA for one hour. Or 1329 mA for 2 hours. And so on. Current times time is a unit of energy,…
Day 1
There is little to say on the first day. I gave myself a full smartphone and a full power bank. In the car on the way to the university, the first big power draw: 45 minutes of audiobook. Charging…
The Smartphone Challenge: A Beginning
In the course of taking part in various seminars and lectures on sustainability, I kept coming across the subject of the smartphone, and I realised that a smartphone is an interesting object in…