Pixeltable Reloaded

You might already know my Pixel-Table from a previous blog post (link). Back then it was powered by a Raspberry PI which had the hazards of managing a full OS and struggling with always-corrupted filesystems after power outages or just after some time when the SD card memory gets broken as of too many write-cycles.

So I started to move the hardware towards Arduino (to control the LED Stripe) and an ESP8266 to offer wifi communication. The two microcontrollers communicate via the serial interface.

Basic outline:
Webapp -> ((Wifi)) -> ESP8266 -> (Serial Interface) -> Arduino -> LED Stripe

Finally I also managed to build a grid for the LEDs so they appear far more pixel-shaped.


  • Pixeltable Hardware as of previous post
  • Arduino Nano
  • ESP8266
  • DIY Webapp to send commands to ESP8266
  • Fun!

Hobbyking Swamp Dawg Air Boat

After I saw the Hobbyking Swamp Dawg Air Boat somewhere on the internet I knew I also had to have one. So I ordered, assembled and ran it. Unfortunately the rumors were true that the motor and propeller it came with is sh*t. So after some rides I upgraded it with components that were recommended in a specific blog (Link).

It now runs mega-fast and with almost no vibrations.


  • Hobbyking Swamp Dawg Air Boat (Link)
  • Some RC sender and receiver
  • Turnigy D2826-6 2200kv Brushless Motor incl. spinner (Upgrade)
  • 30A SimonK 2-4s Brushless Speed Control ESC With BEC 3a (Upgrade)
  • Graupner CAM Speed Prop 5,5×4,3 (Upgrade)

DIY industrial design desktop

This is the desktop I designed and created for my living-room homeoffice corner. I had the idea to design it in industrial style and therefore used standard shawl panels that you normally use for concrete formworks. Especially I like the layered texture of the panels and the visible screws!

I also mounted some AC outlets on the surface so I do not have any annoying cables lying around that normally just act as dust attractors.

My latest addition to the table are USB outlets so I can also charge my mobile devices directly.


  • DokaPly Birch Plates (Link)
  • Some nice-looking AC outlets
  • IKEA RÄLLEN – Integrated USB Charger (Link)

Geeky weeding present


My friends Tobias and Anna got married and as usual I did not have any ideas for a present for a long time. But then I was playing around with the ESP8266 modules in a quiet minute I had a cool idea: As Tobias was the one that brought me to Arduinos & electronics the idea was born to program an ESP8266 to deliver the present:

Once connected to the ESP acting as an AP there should be a catch-all website (“Captive Portal”) giving the lucky couple some nice wedding ascii-art and the present in form of a coupon code. First I wanted to buy some (parts of) bitcoins to give them as a present. Unfortunately I did not have enough time to figure out how bitcoins work and especially how I could buy them to give them away like a coupon code. That is why I ended up using an unexciting amazon coupon code.

Then I mounted everything in a cigar box I had lying around and even supplied instant power using two AA batteries. So to open their present they now just have to power of the ESP8266 and connect to the wedding-wifi. On usual hardware the “captive portal” pops up with the custom wedding greetings and the present. And as the ESP is not soldered directly he can easily reuse the mcu.

I think it this the right way to give an electrical engineer his weeding present. Happy wedding, Tobias!

I just slightly changed the sources I found for the ESP8266 Captive Portal project, so I will not publish any sources here.


Repairing an htc desire 626g+

Right a month after my sister got a new htc desire 626g+ it dropped on the floor leaving it with a broken screen and a dead touchscreen. unless you do not repair it it came useless. So I tried my best – and voilá it is working again.

I bought a replacement (readily assembled display including touch screen digitizer) on ebay and worked my way through until I could replace the screen. As I could not find any tutorials on the internet yet I want to share my experience here.

My lessons to repair:

  • Open the back cover of the phone
  • Remove the surrounding frame. It can be removed with a plektron in the gap between the frame and the front cover
  • Remove all screws on the back and carefully remove the plastic covering the electronics
  • Now you can also remove the battery. It is glued with doublesided tape. Start by lifting it on the side that points to the usb plug. Then unplug the battery connector.
  • Disconnect the two flex cables of the old display. You can see which cables they are when you already have your new display.
  • In the battery compartment is a hole that let’s you see to the back side of the display.
  • Now pick a hairdryer and warm up the front glass of the phone and try to get out the old display element. As it did not work so well for me I just destroyed the glass (actually it was already defective as it was split) and picked out the display partly until I had everything out.
  • Then I cleaned the frame where the old display was taped and inserted the new display with new tape.
  • Connect the cables and assemble everything again.
  • I was happy that it booted up and everything worked.
  • Be carefully and never use too much force. When doing so, you will definitely destroy something! All parts _can_ be removed without too much force and without destroying them (except for the display unit that I did not care about as it was already broken :-)

Here are some pictures showing the insides of the phone. Maybe it can help you repairing your own phone.


IMG_20150817_210948 IMG_20150817_210952 IMG_20150817_211004 IMG_20150817_211009 IMG_20150818_210313 IMG_20150818_210328


Time Measurement for Carrera Slot Car Track


After I had to have my own Carrera slot car track last year I soon wanted to have proper time measurement. First we measured time with a stopwatch app on the mobile – one driving the slot car and another one taking the time. But of course it is inaccurate and it was more and more becoming inaccurate as the night proceeded to fall – blame it on sleepiness, the beer or both *twinker!*

So I began to experiment with the MicroView – my first thing on Kickstarter I actually supported. It comes with an integrated OLED display and is fully Arduino compatible. To document the times I connected a mini thermal printer. I also added some push buttons to change the number of laps for one race and the number of players. Pressing this button changes the current player and the measured time is than properly assigned when it comes to printing the result.


  • MicroView,
  • Mini Thermal Printer + thermal paper
  • Infrared Obstacle Avoidance Sensor
  • 5v switching power supply (Minimum 2 Ampere suggested for printer)

See it in action in the video:


My Pixel-Coffee-Table

I was inspired for this project by the following post I saw on the web: How To Control Adafruit LED Pixels with Raspberry Pi

It explains how you can connect a bunch of WS2801 LEDs to a Raspberry Pi and control it via a web page running on the same small computer. I changed the form factor from pixelstrip-only to a 10×10 matrix of LEDs and added a wooden coffee table and a depolished glass plate around.

It has the same software as in the project mentioned above: Some node.js magic running the web interface and controlling the pixel strip. Big thumbs up tho Andrew Munsell for publishing his sources on Github!

I have a lot of other ideas concerning how to develop the table further:

  • responsive web interface so that it is also nicely usable on mobile devices
  • adding games like Connect 4 or Ludo
  • visualize audio that is heard around
  • visualize data coming from Twitter
  • visualize weather
  • and so on

But at least the hardware is up and running – the rest is software :)

As I use my table next to my sofa I also mounted a normal power outlet to being able to give my laptop some juice and also added two 5V USB power outlets to charge my mobile devices.

So my coffee table will provide the light fx at my next party – and my guests can charge their phone when they run out of battery as they are just taking pictures of my table :-D

[Update 2014-12-02] first idea to use my table:  advent wreath


Making a home for my trinkets, keys and everything else lying around

After I had seen the idea to use small spoons as hangers during my stay in Finland I knew I wanted that too. So I checked some old spoons at the fleamarket, got an old wooden board and voilá! Finally a stylish place for my seldom used things!


Fixing my broken Nexus 4

Got my broken Nexus 4 fixed.

I ordered a new display+glass+touch+frame unit on ebay and watched some video tutorials on Youtube. Was easier than expected.

Welcome back!

Cost: approx. 45eur (including shipping) + 1 hour of work + about 2 hours watching tutorials on Youtube.