My Blog


a blog about projects, teaching, programming and other stuff


Why are free proxies free?

because it's an easy way to infect thousands of users and collect their data


How a scammer stole 500$ from me and in the end begged me not to tell his parents

Thank god not all scammers are professionals


How to defend your website with ZIP bombs

the good old methods still work today


Analyzing 443 free proxies - Only 21% are not shady

what about the other 79%?


DIY: Cheap wall mounted, water cooled PC for 51$

with LED backlight and and all the good stuff


That (not so) awesome time the police raided my home

lesson learned: Don't click on links random people send you


Making a simple Raspberry Pi Bitcoin/Ethereum trading bot

with rocket.chat and Slack status reporting


My door sends me chat messages

Raspberry Pi powered door sensor and Rocket.Chat bot with some neat info


My XP-based grading system

a modern approach to grading in the year 2014


Raspberry Pi controlled LEDs

to visualize the up-state of my servers


My door sends me emails

Simple and cheap Raspberry Pi burglar alarm


Accepting Ethereum payments without external services

You don't need to pay for merchant systems


Creating the safest ETH paper wallet with a Raspberry Pi

with a printer and without an internet connection


Making an awesome dashboard for your crypto currencies in 3 steps

using InfluxDB, Grafana and PHP


How to visualize RADIUS connections

by parsing Windows Server log files


IKEA Server Rack

nope, not a lack rack


Raspberry Pi controlled power sockets

it's as easy as it sounds


DIY cloud lamp for fun and profit

ok, just for fun.. no profit involved


Repairing a closed loop CPU water cooler with aquarium tubing

air bubbles... those f***ing air bubbles


How to fight child pornography with a Raspberry Pi and deep learning

Finding illegal content with just 10 Watts of power


Raspberry Pi temperature monitor

with a nice graph and live updates


Let's analyze over twenty thousand proxies

It won't get much better


DIY hydroponic pot for ~36€

Easy to build and awesome for your plants


Water cooled NAS made from spare parts

with Macguyverish solutions for common problems


Forget Pay2Win - the time has come for Learn2Win

how to reward players in any game for academic achievements


Reverse engineering your mobile banking app

to make a PHP script that automates checking your balances


Raspberry Pi 2 wireless temperature box

The π² + wifi + 1wire sensor = pure awesomeness


Why hackits are the first thing I teach new classes

they represent everything I love about computer science


My company just turned 10 and it was quite a ride

also: about the time Thomas Schranz and I almost invented Dropbox


Raspberry Pi + Deep Learning home security system

From start to finish


Chromebooks for Work & Classrooms

are they worth it?


DIY vertical hydroponic system

grow vegetables in small spaces


Temperature visualization

from 6 months of data


Letting students mod school computers

with some amazing results


hackthissite.org ascii code picture challenge


HTML5 heat spreading simulation

with a simple JS algorithm


Is Guetzli useful in production?

It's much better than google promised - 51% smaller images


Announcing: Socialcube LITE

My proof-of-concept evolved to a intuitive platform which is free for every educational institution


What would happen if you'd embed a remote JPEG with a HTTP link but the remote server is forcing HTTPS?


Neue Reifeprüfung analyzed

The simple way to get a good grade


Finding bombs in the forest

treasure hunters make it easy to find them


PHP script that filters moods from twitter

..how depressed is the web?


API Heaven ICO

finally an ICO for an existing product


Raspberry Pi controlled cactus lamp

adding power to a cheap lamp


Teaching your fish tank LEDs new tricks

for just a few bucks and you can even make some virtual clouds


So you have been scammed

a small guide on how to strike back and be a bad scamee


Making a smart meter out of a dumb one for 4 $

and displaying it on an awesome dashboard