7 easy steps to set up OctoPrint on Raspberry Pi

A reduced to the max step-by-step guide to quickly set up OctoPrint on a Raspberry Pi. If you just need the facts, read this guide!

If you want to remotely control your 3D printer, OctoPrint might be your choice. This is a very, very short seven-step instruction to show, how OctoPrint is set up on a Raspberry Pi. No pictures, no videos, just the plain vanilla facts.

  1. Download Octoprint from octoprint.org.
  2. Flash Octoprint image Use, e.g., Etcher from balena to flash the Octoprint image on a micro SD card. Do not format the SD card even if your operating system asks you to do so. Just flash the Octoprint image on the SD card.
  3. Setup Wifi Re-insert the SD card in your SD card reader. Edit the file octopi-wpa-supplicant.txt in the boot/ directory. Use an appropriate editor to do this. There is a plethora of information out there that explains why this is important; in case of doubt please use a search engine.
    There are two sections in the file that are relevant:
    Take care that you uncomment the country you’re living in and comment out the one that was previously uncommented. Take even more care that you do not only enter the ssid and your password in the WPA/WPA2 section but that you also uncomment the lines starting from network up to and including the line with the single closing brace.
  4. Fire up the Octopi Put the SD card into your Pi, connect a power source and fire it up! Wait approx. 90 seconds until the boot process is completed.
  5. Log in using SSH Use ssh to remotely log into your Pi*. The Octopi will be reachable either by using its IP address (that you will have to find out, e.g., by looking into your router’s attached devices section) or via octopi.local. The latter requires Bonjour to run properly on your computer. Assumed you know the IP address, use this terminal command to log in:
    SSH pi@<ip-address>
    You will be asked to confirm a certificate. Type ‘yes’ followed by a return. Then enter the password. The standard password is raspberry.
    (*Mac users will usually use terminal, Windoze users may want to use PuTTy as a SSH-client.)
  6. Change password Change the standard password using the command passwd. You will be asked to enter the old password then twice the new one. Done.
  7. Access OctoPrint via web browser Start a web browser and enter http://octoprint.local (requires Bonjour service) or http://<ip_address>. You should see the OctoPrint interface and a setup wizard pop up. This page has a table with settings for many common 3D printers. Follow along and be sure to set up a username and password for your OctoPrint.

Now open up the connection panel on the left. With the options set to “AUTO” hit Connect. If the connection was successful congratulations – you’ve successfully set up OctoPrint!

Optional step.

  1. Static IP Out-of-the-box, your Pi will receive a dynamic IP address. I prefer to have a static IP address. When you are logged into your Pi use the following command on the command line to edit the dhcpcd.conf file:
    sudo nano /etc/dhcpcd.conf
    Go to the section that looks similar to the following lines…
    …and enter your desired IP address, your router’s IP address, and, optionally, your preferred domain name server(s). The ones above are the Google DNSs. Use sudo reboot to reboot the Pi.

MacOS Finder: Spaltenreihenfolge dauerhaft ändern

Reihenfolge der Spalten im MacOS Finder dauerhaft ändern. Hier eine Schritt-für-Schritt-Anleitung, wie man die Spaltenreihenfolge geändert bekommt!

Die Reihenfolge der Spalten im MacOS Finder lässt sich einfach durch drag’n’drop den eigenen Bedürfnissen anpassen. Es ist jedoch zu beachten, dass sich die geänderte Reihenfolge stets nur auf das aktuelle Verzeichnis bezieht. Soll die aktuelle Reihenfolge für alle Ordner gelten, so ist der View Options Dialog via CMD + J zu öffnen und nach dem Ändern der Reihenfolge unten der Button “Use as Defaults” zu drücken.

Aber: Das reicht in der Regel nicht! MacOS merkt sich Ordner-spezfifische Einstellungen in der, in jedem Ordner vorhandenen, Datei .DS_Store. Und die in dieser Datei hinterlegten Einstellungen haben Vorrang vor den globalen Einstellungen, die via “Use as Defaults” eingestellt wurden (selbige werden in com.apple.finder.plist abgelegt, just for the Nerds).

Das Vorgehen, das bei mir zu dauerhaftem Erfolg geführt hat, ist wie folgt:

  1. Reihenfolge der Spalten im Finder anpassen.
  2. CMD + J und dann “Use as defaults”.
  3. Im Terminal sudo find /Users/<username>/ -name .DS_Store -delete eingeben, Return. Dies löscht alle(!) .DS_Store Dateien in allen Verzeichnissen. ACHTUNG! Eine Falscheingabe dieses Befehls kann zu ernsthaften Schäden am System führen. Wer nicht weiß, wie dieser Befehl funktioniert und was da genau passiert, BITTE LASSEN.
  4. Finder neu starten: Entweder im terminal mit killall Finder oder mit Alt + Rechtsklick auf das Finder-Icon im Dock und dort dann “Relaunch” wählen.

Hernach sollten vom Finder alle Verzeichnisse mit den Spalten in der gewünschten Reihenfolge anzeigen.

How to convert 3MF files to stl format on a Lin*x machine (including Mac)

3MF is a file format for 3D printers with inbuilt DRM. Some slicers are not able to read 3MF files. Here is a way to convert such files to STL.

If you need to convert a 3MF file to STL format you may find that there is no really simple solution. I found this very useful blog post by Zebethyal that describes how the command line tool 3mf2stl by Charles Shapiro can be compiled on a Mac to convert 3MF files to STL format. The required steps in all brevity:

  1. Install Homebrew
    Open terminal and type (all in one line)
    ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" < /dev/null 2> /dev/null
    Hit return. Homebrew is downloaded and installed.
  2. Install libzip
    brew install libzip
    After hitting return, the libzip library will be installed.
  3. Download 3mf2stl
    Enter the following URL in your browser
    and download the 3mf2stl repository (green button to the right, download as ZIP).
    Unzip the file to a directory, e.g. ~/Documents/3mf2stl/
  4. Compile 3mf2stl
    Change to this directory
    cd ~/Documents/3mf2stl/
  5. and type
    Hit return. The code will be compiled.

If the compilation was successful you will have an executable named 3mf2stl in this directory.
Usage is ./3mf2stl -i <input_file.3mf> -o <output_file.stl>

How to get rid of MacOS’ “one or more items can’t be changed because they are in use”

Sometimes MacOS locks files and you cannot copy, move, or delete them. Here is how to get rid of this "one or more items can't be changed because they are in use" behaviour.

MacOS can be annoying, at times. In this case I was struggling with a video file that could not be copied, moved, or deleted because MacOS persistet on telling me it “can’t be changed because [it is] in use”; cf. this screenshot of the popup message.

The Continue-Button might suggest that MacOS would perform the action if I clicked it. But after clicking continue, I was asked for my admin-password, the file would seemingly get copied (or moved etc.), and finally, the copied (or moved file etc.) would be deleted.

It took a lot of searching until I, finally, came across the solution in this thread. I did not dig into the gory details of the cause but it has something to do with the so-called extended file attributes. You can see if a file has extended file attributes when you do a ls in the terminal. If there is an @ on the right-hand side of the file permissions this file has extended attributes set. As was the case with my video file:

> ls
-rwxr-xr-x@ 1 zzz  staff  42164199 Dec 19 18:58 MAH07541.MP4

Using the -l@ flag we can see the extended attributes that are set for the file:

> ls -l@
-rwxr-xr-x@ 1 zzz  staff  42164199 Dec 19 18:58 MAH07541.MP4
	com.apple.FinderInfo	      32

So in my case it’s the com.apple.FinderInfo attribute that was causing the problem. As soon as I deleted the extended attribute using

> xattr -d com.apple.FinderInfo MAH07541.MP4

everything was back to normal and the file could be copied, moved, or deleted.

Be careful when you are fiddling with the extended attributes since they can also store resources or essential file metadata. A user in the above mentioned thread says that it is “…always safe to delete com.apple.FinderInfo”. Well, that is something you will have to decide on your own.

How to restart iPhone 8 (Plus|X) when you can’t shut down

How to force-reboot an iPhone 8 (Plus|X) that acts weird? We show the new three steps to reboot since the process has changed from previous iPhone versions.

The process of restarting your iPhone has changed with the advent of the iPhone 8, iPhone 8 Plus or iPhone X.
Such a restart, or hard reset, is necessary if your iPhone is acting weird like you are not able to shut it down by long pressing the side button or you can’t start apps etc.

The force-reboot is no longer achieved by pressing the side and home button simultaneously. Now you have to use the following sequence:

  1. Press the volume up button once.
  2. Press the volume down button once.
  3. Press and hold the side button until the Apple logo appears (approx. ten seconds).

That’s it, your iPhone should reboot. In case you protect your iPhone using a PIN, which is recommended, you will have to enter your PIN after reboot.

Webhosting (nicht nur) für echte Kommandozeilen-Nerds

Viele große und auch kleine Webhosting Massenanbieter haben gewisse Herausforderungen. Hier (m)eine Lobeshymne auf die große Ausnahme "uberspace".

Ich hab’ sie alle durch, die Massen-Web-Hosting-Anbieter. Eine nicht vollständige Liste in zufälliger Reihenfolge: Host Europe, all-inkl, Strato, Hetzner, alfashosting, goneo, GoDaddy, Celeros usw. usf. Das könnte ein langer, langer, geradezu ausgesprochen langer Rant darüber werden, was in schöner Regelmässigkeit bei denen alles nicht funktioniert bzw. funktioniert hat. Aber da muß jeder seine eigenen Erfahrungen machen. Und es ist auch gar nicht auszuschließen, dass jeder der genannten Dienstleister seine passende Zielgruppe hat, für die alles, sagen wir mal, irgendwie und gefühlt läuft.

Für mich war jeder Webhoster-Wechsel immer mit der Hoffnung verbunden, nun jemanden gefunden zu haben, der sein Geschäft im Griff hat. Aber eigentlich gab es immer nur Variationen der bekannten Ärgernisse: Support mit durchwachsener Fachkenntnis, träge Reaktionszeiten, Standardformulierungen, Geschwindigkeitsprobleme und Security Issues. Gerade der letzte Hoster setzt mit seiner technischen Inkompetenz insbesondere im Bereich des Server Hardenings dem ganzen noch einmal eine unrühmliche Krone auf. Der Name sei nicht genannt denn hier soll niemand diskreditiert werden.

Ganz im Gegenteil: Ich möchte hier einen Webhosting-Anbieter hervorheben, nein, geradezu anpreisen, der mir über die letzten zwei Jahre extrem an’s Herz gewachsen ist. Und das nicht, weil ich besonders oft den Support gebraucht hätte. Das war nur einmal der Fall und es gab innerhalb von Minuten eine fachlich extrem versierte Antwort, die konkret auf mein Anliegen einging und sofort weiterhalf. Das allein hat beim Martyrium aus IVRs, bestenfalls halb gelesenen E-Mails und Antworten, die dann nur noch auf ein Viertel des ursprünglichen Anliegens eingehen, schon extremen Seltenheitswert.

Katze aus dem Sack: Es geht um uberspace.de. Aus meiner Sicht kein klassischer One-Klick-To-Happiness-Webhoster mit Klicki-Bunti-GUI, sondern eher was für technikaffine Maker, die den Umgang mit der Kommandozeile nicht scheuen. Man muß sicher kein Web-Guru oder Un*x-Admin sein, aber schonmal in der Shell gearbeitet zu arbeiten, hilft sicherlich bei der Einrichtung des eigenen Web-Space. Allein daran sieht man schon, dass uberspace irgendwie … anders ist. Positiv anders.

Ein anderes Beispiel: Wer auf der Kommandozeile seine Domains, Mail-User oder den SpamAssassin verwalten möchte, der braucht eine Dokumentation. Die gibt es in Form eines umfangreichen WIKIs, das meiner Meinung nach kaum Wünsche offen lässt. Und noch etwas fällt sofort auf, wenn man das WIKI oder auch die Webseite durchliest: Kompetenz pur. Und Überzeugung. Beispielsweise, was die Preise/Bezahlung anbelangt. Jeder entscheidet selber, wieviel er uberspace bezahlen möchte. Auch die Abhandlungen über den Verzicht auf die Lastschrift (bezahlt wird per Überweisung) oder ganz generell immer wieder die Erläuterungen, warum das Team von uberspace die Dinge so macht, wie sie sie machen, sind absolut lesenswert.

Es gibt kaum eine Text, eine Erläuterung oder sonst eine Stelle, an der ich nicht einen Haken machen könnte. Selbst im gerade durchforsteten Impressum gibt es wieder etwas, wovon sich andere Seitenbetreiber etwas abschneiden könnten. Die meisten klicken sich ihren Impressums-Sermon bei erecht24 oder sonst wo zusammen und klatschen dann diesen Text mit mehr oder weniger Verstand auf ihre Seite. Bei uberspace finden wir aber: “[…] In Sachen Linkhaftung sparen wir uns den sonst üblichen Disclaimer, der nach Meinung der meisten Juristen ohnehin keine Rechtswirksamkeit entfaltet. […]” Ita est!

Ich bin schlichtweg begeistert von uberspace und wünsche mir inständig, dass sie im Rahmen der eigenen Ansprüche und Wünsche prosperieren und damit allen, die einen wirklich richtig guten Webhosting-Dienstleister haben möchten, lange erhalten bleiben!

I18n: nullseite.de goes zeropage.io

Not really a matter of internationalization but the Nullseite has to give way to the zeropage.

The king is dead, long live the king!

I started my private blog Nullseite BOY 2008. Since then it experienced two rebrushes and got an accompanying offspring EOY 2015 – the zeropage. There is only so much spare time one can spent on blogging (and other stuff;-) so I decided to quit trying to curate two blogs at the same time. The Nullseite will diminish as I am in the process of migrating the most worthy Nullseite-Posts to the zeropage. This requires some tedious manual labour and will, thus, take some time. Stay tuned!

How to run Netgear ProSafe Utility on MacOS

Netgear does not offer a Mac-Version for their ProSafe Plus Utility. Since it doesn't run reliably with Wine, you'll have to use virtualizers like Parallels or VirtualBox.

Netgear is offering his switch management software “ProSafe Plus” for Windows. And for Windows only. Well, they just might have not noticed that there is at least one other very popular operating system in the market. Such things happen.

To still run ProSafe on a Mac and avoid the overhead involved by installing hardware virtualizing suits like “Parallels Desktop” or “VirtualBox”, I tried to use the compatibility layer software WINE to run ProSafe.


WINE requires XQuartz first, then Wine for MacOS can be installed. After that you can right click an arbitrary Windoze *.exe file and “open with…” Wine. Unfortunately, the ProSafe Plus Utility did not install smoothly. Had to restart the installation process a couple of times but could start the ProSafe Utility only once. Digging into Wine’s website winehq.org you will find that other users already reported about problems with the installation of ProSafe. To sum it up: No easy way this time. Let’s do it the hard way.


The hard way means that you will have to use a hardware virtualizer like VirtualBox or Parallels Desktop. And, apparently, you will need Windoze. Luckily, I had an old Windoze 7 installation CD lying around. The first step is to install the free virtualizer VirtualBox by Oracle. The installation process is pretty straightforward and to just run the ProSafe Utility you should be fine with the standard settings suggested by the installer.

You will, most likely, have assigned an ISO-Image of your copy of Windoze during installation. After VirtualBox has been installed, start the Windoze Virtual Machine and get your copy of Windoze installed in the Virtual Machine. That might take some time. After successful installation of Windoze you can reboot, log into your Windoze account and install Netgear’s ProSafe Utility.

After installation of the ProSafe Utility fire it up and, if all went well, you might see a screen similar to the following one. The ProSafe utility scans the network and will list all discovered switches. My switch, a GS108PEv3, hast been found and I am, finally and after all that hassle, ready to configure the switch.

Nightlight Late-Night Edition

A 3D printable night light with Arduino-controlled LED light effects and a virtually arbitrary number of front designs (limited only by your creativity).
This project powers electronic components (5V) with a mains supply circuit (230V > 5V) that is connected to a power plug (230V). If you are going to build this, make sure that you know what you do. In case of doubt, consult a skilled person that is familiar with mains voltage or use a safe power source like a line adapter or batteries.

tl;dr A nightlight based on a reworked Thingiverse design with Arduino-controlled LED light effects, touch sensors, and a piezo buzzer humming the first notes from the Imperial march. Watch the video to see it in action. Detailed instructions start below video.

Bragging rights

The rocket nightlight was presented in the German MAKE magazine 06/2016 as a community project. Thank you! 🙂

The link or a click on the picture take you to the table of contents of issue 06/2016. If you have questions concerning this project do not hesitate to contact me! <foobar@zeropage.io>

Project Description

You can find a great design for a LED nightlight with various emblems or logos like Stormtrooper, Superman, Punisher, etc. on Thingiverse. This design is based on a 3D printed case with a transparent and extruded inlay of the emblem/logo in the lid. The case has a hole on the backside to have an external power supply feed the internal light source, e.g., an RGB light stripe or similar.

I reworked this design to create a nightlight that

  • does not need an external power supply, i.e., has a plug and can be directly plugged into a wall socket
  • has touch switches to easily adjust the brightness, light effects (or modes), colors etc.
  • uses a piezo buzzer to acknowledge touch switch triggers and to play the first notes from the Imperial March when plugged into a socket (a little annoying, but can be switched off;-)
  • utilizes a mounting platform for six RGB LEDs that can be easily inserted into the case
  • fixes some minor issues in the original design (displaced inlay and mounting hole)
  • comes with a variety of light effects like fixed colors, strobe, or cyclone chase


1 x Arduino Pro Mini 5V 16MHz // Merchants on eBay offer a plethora of pro minis. Take care when ordering: The pro mini is available as 3,3V and 5V as well as 8MHz and 16MHz versions. Moreover: Many vendors are located in China; shipping may take a long time to your home country.
1 x Piezo buzzer // One of these (eBay) should work.
1 x Power supply // I used this EMSA050120, 5 V-/1,2 A from Pollin to harvest the mains supply circuit and the plug.
4 x 3D printed part // These parts comprise a case, an LED holder, a plate (or lid) and an emblem/logo. You will find the 3D templates as STL files on Thingiverse.
6 x RGB LED // The WS2812b have a nice color range and are usually cheapest when bought as an LED stripe. I had some spare LEDs from another project. You can order them on eBay or here (1m stripe, Roboter Bausatz Shop).
4 x M5, 16mm counter-sunk screw
1 x Software // The software for the Arduino is available in my Nightlight Late-Night Edition repository on GitHub.

Moreover a Dremel or similar to cut open the mains adapter, pliers, rasps, wires, some metal splints for the touch sensors, and, of course, a soldering iron.

Nightlight 3D Parts

The nightlight consists of four 3D printed parts; cf. the sandwich picture showing the different layers.

nightlight layer view

From bottom to top: 1) Case to host the mains supply circuit, Arduino pro mini, piezo buzzer, LEDs, touch switches, cables, and the plug. 2) LED holder. 3) The top plate and 4) the extruded emblem inlay.

3D Part 1: The Case

The case from the original design was only 13mm high (inner height) and, thus, not tall enough to host the electronic parts. I had to import the STL file into SketchUp and stretch the case on the z-axis to an inner height of 25mm. That gave me just enough space to squeeze the LED holder above the mains supply circuit into the case and still have 2 or 3mm distance from the top plate. The more space you have between the LEDs and the plate, the better the light will be diffused. But I did not want the nightlight to be more bulky than necessary so 25mm inner height had to suffice.

Increasing the height was the easy part. Designing the plug holder on the backside of the case was more difficult. I first measured the dimensions of the plug as precise as possible, then started to design a plug holder with SketchUp.


It took a couple of iterations and an according number of test prints until, finally, the plug snapped into the plug holder with a satisfying “click”. The plug fits so tight that I consider it to be unremovable without destroying the case. And I may add that this is by design since we are dealing with 230V AC power and the nightlight must be impenetrable by adventurous kid’s hands.


The case was printed with black REC PLA at 210°, bed temperature 60°, no support, 0.16mm height, 1.2mm wall thickness, and 66% infill. It depends on your 3D printer’s bridging abilities if the plug holder will be ok without support. If unsure, print the case with support turned on.

3D Part 2: The LED Holder

I wanted the LEDs in the nightlight to be on a planar surface to get an even illumination. The idea was to construct an LED holder in SketchUp that tightly fits into the case without gluing, is rather stable, and has legs to stand on. The images show what I came up with.


Luckily, the LED holder nearly immediately matched all of the above mentioned criteria. I chose white innofil3D PLA for the print since a white background looked best behind the semi-transparent inlay.

3D Part 3: The top Plate

The plate was printed with black REC PLA and the same print parameters as for the case (210°, bed temperature 60°, no support, 0.16mm height, 1.2mm wall thickness) except that infill was set to 100%. I did not want any light to escape through the plate. With a proper number of top and bottom layers 100% infill with black PLA might be an extreme overkill but I played it safe.


With 100% infill the plate came out rock solid which has another advantage: Some parts might need to be sanded so that the extruded emblem/logo wil fit into the plate. The more solid your parts, the better they can be sanded.

3D Part 4: The Emblem/Logo

The extruded rocket inlay was printed with transparent innofil3D PLA. You will notice that “transparent” is in no way comparable to acrylic glass or alike. Moreover, parts printed with this PLA look yellowed; like they have been exposed for too long in the sun. Nonetheless, this kind of transparency is the best you can get with current fused deposition modelling (FDM) based desktop 3D printers and PLA. Nylon and other filament materials might yield better results but they are more difficult to print and handle.
Infill was set to 22%. You will see the honeycomb pattern, or whatever type of infill you chose in your slicer, with such a low infill value. But more infill also means losing transparency. I was fine with 22%.

Avengers assemble!

Let’s put the hardware together.

Complete the Plate

The transparent emblem/logo has to be merged with the plate. Depending on the design there might be a couple of “loose” parts from the plate print that need to be inserted into the emblem/logo first. Rasps and sanding paper are your best friend in this step since the parts will most likely not fit straight off the 3D printer. While 3D prints are usually pretty nice, there are limits to the precision you can expect from FDM prints. The rocket has only one loose part which is the round window. That one is pretty easy to insert. If not, rasp and apply mild force. Do not apply too much pressure to the small parts – they might break or damage the plate. If in doubt, sand more and re-try often. It will finally fit. If all loose parts are pushed in the emblem/logo you will want to merge the emblem/logo with the plate. That might need some sanding too. The small and tall middle wing of the rocket will most likely need some sanding. Be very careful since it can break off easily. Carefully push the transparent part into the plate. A vise or a hammer might come in handy, depending on how brave you are. This step requires patience.

Disassemble the Power Supply

As mentioned in the Payload-section I used a very cheap EMSA050120 power supply from Pollin to harvest the mains supply circuit and the plug. The case turned out to be very intractable and successfully resisted my attempts to pry it open it with a screw driver or pliers. I could have tried to pop it open in the vise but did not want to risk damaging the PCB/electronics inside. Well, let’s mill it open – Dremel time!


Caveat: Always mill with safety glasses and use protective gloves. The picture is just for demonstration purposes. Milling plastic produces foul-smelling, and most likely toxic, fumes. Do it outdoors. The picture in the middle shows the mains supply circuit along with the plug. In the next picture you can see the backside of the supply circuit with the big L- and N-conductance pads on the right-hand side of the PCB.

Solder Wires on Plug

The plug will be connected with solid copper cables to the L- and N-conductance pads of the mains supply circuit.

There is an ongoing discussion whether 230V connections ought to be crimped or if they are allowed to be soldered. If you decide to solder make sure that a) the soldered parts are perfectly solder joined and b) voltage isolation in terms of the dielectric strength of the used materials, creepage and clearance has been considered properly.

Before we can solder the cables two small plastic bars have to be removed from the plug. I use pliers to simply break them off. After that I start to solder the cables on the plug’s connection pads (to the left and right of the middle screw). Or I tried because this turns out to be an epic soldering fail. I try a dozen times but can’t get the, sorry, GODDAMMIT cables to solder-join with the pads. The pads literally refuse to be soldered! But resistance is futile and a couple of search engine queries later I seem to be wiser: The pads are made of stainless steel which is pretty hard to solder with normal tin-solder. If not impossible at all. What I need is soldering fluid, something like this (Conrad).


If you read the soldering fluid’s hazard notes, well, you do not really want to use this stuff: Serious chemical burns of skin and eyes, irritating to the respiratory system, and so on and so forth. Zinc chloride is no fun. Keep away from children! After some more failed attempts even with the soldering fluid I learned that the pads need much more heat to join forces with the cables than I was used from soldering usual electronics stuff. So, finally, I got two nice solder joints. FTW!

Drill Holes for Touch Sensors

stormtrooper-nightlight-drill-holes It is always a good idea to think before you act. And I wish I’d done that before printing the case since I forgot to add two 4mm holes for the touch sensors on the right-hand side of the case! Facepalm! Printing the case again just because two holes were missing was not an option. But we are not only apt with additive but also with subtractive manufacturing: I drill the holes with a 3mm wood drill and get a perfect diameter after some minor rasping. PLA is fairly easy to drill, e.g. compared to acrylic glass. But you may have to lift the drill from time to time to remove excess plastic. Wood drills are designed to automatically forward the excess wood to the top of the drill and out of the drill hole. When you drill PLA or other plastic materials it tends to melt and get stuck on the drill. The slower you drill, the better. Applying some drops of water or sewing-machine oil is said to help (not tried so far).

Connect Mains Supply Circuit to Plug

In this step we connect the mains supply circuit to the plug and fix the circuit in the case.

Voltage isolation: As already mentioned you will have to take care of proper voltage isolation when dealing with 230V. The pictures show how I did it but they do not claim to be a blueprint for proper electronic handling especially with respect to mains voltage isolation. I would suggest to use spacers to attach the mains supply circuit to the bottom of the case so nothing on the flipside of the PCB can touch the case. Moreover the whole mains supply circuit including the soldered wires should be isolated from the rest of the electronic parts which can easily be achieved by enclosing it with an additional 3D part. As always: In case of doubt, ask an expert!

First pop the plug into the case’s plug holder. Since the copper wires are pretty rigid it is a good idea to shorten and bend them properly before soldering the wires to the mains supply circuit.


Solder the mains supply circuit’s L-conductance pad to the brown copper wire. Repeat with the N-conductance pad and the blue wire. Finally, attach the mains supply circuit to the bottom of the case. You can see the black and red 5V power supply cables on the left-hand side of the mains supply circuit. We will use these later to power the LEDs and the Arduino microcontroller.

Attach LEDs to LED Holder

stormtrooper-nightlight-attach-ledsI decided to use six WS2812b LEDs and arranged them on the holder in a pattern that showed the most even illumination level during my tests. In case you’re a Lumen junkie there is enough room to cramp more LEDs on the holder. The LED strips usually come with sticky tape on their backside so gluing them on the holder is easy. After that I used 0.15mm enamelled copper wire to solder the connections between the +5V, GND and DOut->DIn pads. Keep the soldering time short to avoid melting the LED holder! The enamelled copper wire is a little tricky to solder because of the enamel coating. I suggest to first remove the enamel, e.g., by applying some tin solder, and then solder the wire to the LED pads. It’s more difficult the other way round. BTW: There is really no need to use enamelled copper wire. It looks nice but using them was more about aesthetics than function. Moreover, the enamelled copper tends to break at the solder joints. I recommend litz wire with a small diameter – easier to solder, less risk of breakage, same function.

Prepare the Touch Sensors

stormtrooper-nightlight-touch-sensors This nightlight requires two touch sensors to control its various functions. The Arduino library ADCTouch makes it very easy to add touch sensors to a project. You can connect nearly everything that changes its capacity when touched to an arbitrary analogue pin of the microcontroller and have that thing act like a touch sensor. In this project I use two small metal splints that will be stuck and glued in the drilled holes on the right-hand side of the case. To connect the splints to the Arduino I have to solder wires to them. Since they are made of stainless steel, I have to use soldering fluid again. One drop on each splint, plenty of heat, a little tin solder, and some heat shrink tubing later the two touch sensors are ready.

Wire it up!

The Fritzing breadboard view shows how the electronic components are wired up to the Arduino pro mini.


You can choose different pins on the Arduino by adjusting the Arduino Sketch accordingly.

  • +5V from the power mains supply circuit goes to the VCC pin while ground is connected to the GND pin on the Arduino.
  • The piezo buzzer’s negative pole is connected to the GND pin, the positive pole to pin 12.
  • The upper touch sensor goes to pin A0.
  • The lower touch sensor goes to pin A2.
  • The view shows symbolically only one LED, not the wiring of all six LEDs. The first LED’s Din is connected via a 220 Ohm resistor to pin 10. It is usually advised to use a resistor to cover power spikes that could harm the LEDs. VSS or +5V on the LED is connected to the VCC pin on the Arduino. VDD or ground on the LED is wired to the a GND pin.

That’s how it looks like when all components have been soldered and put into place in the case.


Regarding voltage isolation: The 5V and 230V components should be properly isolated from each other. An additional layer that encloses the mains supply circuit and separates the 230V wires from the rest of the circuit is currently work in progress.

I used hot glue to paste the Arduino and the piezo buzzer on the case. The touch sensors were easier to attach with super glue.

Light and Diffusion

We need to diffuse the light that is emitted by the LEDs so that the transparent rocket is evenly illuminated. I already had some experience with diffusion materials from another project where I tried normal paper with different grammages, frosted acrylic glass, and Ripstop. The results were ok, but not perfect. I followed a hint that white baking paper yields good diffusion results. Unfortunately, I was not able to find white baking paper; only the usual brown one. Next I tried sandwich paper (sic!) and that’s what I found to work best when it comes to LED light diffusion. Of course, it depends on what you are building and especially, how much space there is between the LEDs and the material of the boundary layer. Try different materials and find the one that best suits your needs. However, I like the sandwich paper and, thus, taped a double layer on the backside of the plate. After that, the plate is screwed to the case with four black M5x16mm counter-sunk screws. I wanted screws with no imprint on the screw head but did not pay (enough) attention to the seller’s pictures on eBay. So, always take a very close look at what you intend to buy. 😉 NB: The screws have to cut their way through the holes in the case so it can get tedious to get them in. Use appropriate force. Moreover, the screw heads were bigger than expected so I had to widen the reception holes on the lid’s front side with a hand countersink.

Code is Poetry

All that hardware does not do anything without the proper software. We need a sketch (aka program) for the Arduino pro mini so the nightlight will do the things described in the project description. Two of the used libraries are worth mentioning: The awesome FastLED library to control the RGB LEDs. And the ADCTouch library to easily turn a cable or a splint into a touch sensor. The sketch makes use of the Arduino’s inbuild non-volatile EEPROM to store modes, colors, and other stuff that can be reloaded the next time the nighlight is powered up. The most complicated part of the code is handling the touch sensors. Both sensors react to short (1st function), middle-long (2nd function) and long touches (3rd function) and trigger different functions depending on the touch durations. Sounds complicated, but is not. Or is it?

Upper sensor

  • Short touch. Increase brightness of LEDs until maximum is reached (17 steps). Then turn LEDs off.
  • Middle-long touch. Immediately return brightness to lowest setting, i.e., one step above zero.
  • Long touch. Toggle playing Imperial March on power-up on/off.

Lower sensor

  • Short touch. Change color, speed, or whatever of current lighting mode.
  • Middle-long touch. Switch to next light mode.
  • Long touch. Immediately switch to first light mode, i.e., fixed color.

You can find the code in my Nightlight Late-Night Edition repository on GitHub.

Ready Player One

That was a real fun project and the roket nightlight turned out to be a full success!

Sep 2016, i.f.

Lord Overhaul: How to fix a rake’s missing wing nut

A lost wing nut is no reason to buy a new rake. Neither is an evil coarse pitched screw. Swap the screw, print a wing nut, and fix it!

Our rake lost its wing nut that is used to fix the pusher for the blades.

Rake repair lost wing nut

On first inspection I thought, that I just take any other M5 wing nut and that thing is good for another ten years of gardening service. But far wrong. The ISO metric screw threads (Wikipedia) come in different pitches: fine, middle, and coarse (at least in Germany). The thread in the rake must be either middle or coarse. At least none of my fine nuts fits on the thread.

So what now? Make or buy? Buy a couple of wing nuts? Buy a new rake? Of course not. Let’s replace the screw with a M5 fine pitched one.

the screws

First step: Pry open the lid. Done. Second step: Remove the old screw. Not an easy task since the manufacturer first drilled a hole and then pushed or hammered the screw through the hole so it stuck really, really tight. After a couple of miserable attempts to remove it with pliers I realized that there is only one appropriate tool for this job: A hammer. The evil screw is out.

Lid and evil screw

Let’s see how we get the new screw attached to the lid. Soldering stainless steel is difficult. Welding would surely work but is somewhat impossible without weldering equipment. Last resort: Glue! Hot glue, not durable enough. The same might apply to super glue. But two-component power putty should be fine.


Funny thing: I do have nuts, but no wing nuts! Duh! So let’s print a wing nut using the awesome Ultimate Nut Knob Generator (Thingiverse) by wstein. Here it is.


I super glued a washer on the outer side so the PLA will not be squashed or damaged when the wing nut is tightened. Now it’s time to put the pieces back together.

rake repair - all parts ready to be assembled

Avengers assemble!

Rake repair done

All set and done. Let the gardening begin!