Update 3 on May 20, 2020: Build log Tronxy X5SA Pro

The SKR 1.4 Turbo board and 4.5 TFT E3.0 display arrived and replaced the Tronxy controller and display. I mounted the controller on the right side of the printer, as I intend to close the build chamber.

With the tmc 2209 drivers I do not need the endstop switches anymore. The inductive probe can be used for probing and Z-endstop (I had to solder a zener diode). It is WIP and there is much left to do. Here is my first benchy with the new controller (1 mm nozzle):

Problems with ABL and Octoprint are now gone…. ๐Ÿ™‚

If you interested in my marlin configuration, here is my fork: https://github.com/FotoFieber/Marlin

Update 2 on May 9, 2020: Build log Tronxy X5SA Pro

What a cool idea: a Quick Tool Change found on https://www.thingiverse.com/thing:3369444

I adapted it to the Tronxy X5SA Pro https://www.thingiverse.com/thing:4337090

Then I remixed my remix of the V6 hotend for this Quick Tool Change https://www.thingiverse.com/thing:4345021

Inspired by all the ideas I found on thingiverse, I tried to print petg….

The build surface peeled completely off the build plate at 85 degree celsius. ๐Ÿ™

(I have some blobs in my print too. The 1 mm nozzle must be tuned in in Cura.)

I sanded the surface down and try now with glue stick:

And then the filament run out and the chitu controller didn’t signal it to octoprint….

It is high time, the orders from china arrive:

  • new build surface
  • skr 1.4 turbo controller

Update 1 on april 22, 2020: Build log Tronxy X5SA Pro

Printed some nice drawers for my screws and nuts. Z-leveling is a pain as the two z-axes always get out of sync. I found a fix for the Tronxy X5SA https://www.thingiverse.com/thing:4297432 and adapted it for my setup: https://www.thingiverse.com/thing:4305634

The problems with octoprint may be fixed with a new plugin: https://plugins.octoprint.org/plugins/fixcbdfirmware/

The build plate is worn out, the coating peels off. I now print with a cooler heat bed and wait until it is cold, before I take the prints off. Hopefully the z-axis fix does bring a further relief.

Build log of my Tronxy X5SA Pro up to april 17, 2020

This blog post reflects the fun I have with my Tronxy X5SA Pro as of the time of this writing.

This is the 5th 3D printer after

  • XYZ Da Vinci 1.0
  • Wanhao Duplicator i3
  • Tevo Tarrantula
  • Prusa i3 MK3S

I wanted to build a CoreXY printer and didn’t want to wait for the one Prusa announced lately.

Some days before the review on Teaching Tech I ordered the printer on Aliexpress. After this review, I expected to have a lot of fun with it. ๐Ÿ™‚

Building this printer was easier than the build of my prusa printer. But I soon recognized I have to change many things:

  1. Replaced belts with fiber inforced ones. They can be better tensioned.
  2. Replaced hotend with a E3D V6 as the original one clogged to often and I want to use my V6 nozzles. https://www.thingiverse.com/thing:4265612
  3. Repaired path of the cable chain: https://www.thingiverse.com/thing:3390159
  4. WIP: Repair belt path:
    1. straighten it
    2. replace most of the belt pullies with GT2 22 M5 versions, to reduce rattle
    3. replace the construction of the front GT2 pullies with a more stable ones
  5. WIP: Repair z-axis: the two motors get always out of sync. Temporary fix: https://www.thingiverse.com/thing:4274159
  6. ToDo: Replace filament runout sensor as he is eager to eat my filament and doesn’t like to let it to the extruder. ๐Ÿ™‚
  7. ToDo: Replace control board, as it isn’t running nice with ocoprint and the data from the bed leveling doesn’t seem to be taken into account when printing. The board doesn0t use marlin and can not be flushed with it.
  8. Support was not really helpful.

… to be continued

webthings (mozilla iot)

Did I get it right?

Sometimes you rub your eyes and think, did I really get it?

This happened to me when I looked at mozilla iot aka webthings.

What is mozilla webthings really? You get software, where you can integrate different IOT systems (e.g. zwave, mysensors…) and have a UI where you can define rules.

I digged down to the api and didn’t find anything about security….

There are example sketches for esp8266 or esp32 to implement webthings that don’t need a gateway to webthings. When looking at the source code, you rub your eyes and ask:

Where is the enxryption of the communication channel (e.g. https)?

Where is the authentication (e.g. basic auth, or at least key hashed requests)?

Maybe I am blind (or I am getting to old…) … investigate yourself… ๐Ÿ™‚

Comments are welcome…

Project: Evaluation of CO2 sensors

some sensors still in calibration phase

In my home automation system I use CO2 sensors from Netatmo and some MH-Z14A based arduino nodes.

I really like, that the Netatmo sensors work for about a year on battery. But they can only be integrated with a cloud api into my home automation. This has led to one interruption of several hours in the past, when the service was down. As I regulate my heating with the measured data of these sensors, this was problematic. ๐Ÿ™‚

What I am missing with the battery powered Netatmo sensors, is a led indicating air quality.

To remove the dependency of the cloud api, I decided to build my own sensors. But before I order more MH-Z14A sensors, I want to make an evaluation.

Caution: This article is about the experiences I made in my setup with the sensors I have and with the (maybe buggy) code I wrote. It may be, that you can not reproduce my findings. ๐Ÿ™‚

evaluate CO2 sensors for Netatmo replacement


  • I don’t want to be dependent on cloud
  • I wan’t a led indicating air quality with every sensor


  • prototype with every sensor
  • graphs of measurements made with different sensors
  • decision for one sensor


  • buy samples of different sensors
  • build a prototype with all sensors
  • make measurements, store them in influxdb and make graphs with grafana
  • evaluate the measurements


  • 20190409
    • Prototype built with MH-Z14A and CCS811
    • API Endpoint with node-red configured to store data in influxdb
    • first dashboard in grafana implemented
    • other sensors ordered
  • Progress 20190424
    • MH-Z19b arrived


  • na

open items:

  • na


The CCS811 seems to reset sometimes (no values for several minutes and then starts with 400ppm). I will add a pull up resistor on the I2C bus.

CCS811 is quite complex to handle. It has a MCU and you can make firmware updates. The library from adafruit is incomplete, it doesn’t support baseline-functions, which you have to use. I changed to the sparkfun library.

CCS811 didn’t show usable results in mode 3 (measurement every 60s). Now trying mode 1 (every 1s) with a moving average over one minute.

MH-Z19b arrived

OSS gem motioneye

Over the last 20 years I used many different video surveillance software.

I started with open source software on linux (motion), then switched to Surveillance Station on a Synology nas.

After that I changed from Synology to Qnap and Surveillance Station was not available back then. I switched to Netcam Studio which is really nice, but requires windows.

QVR Pro from Qnap evolved and is quite usable. Unfortunately it only supports motion detection on two cameras. I was playing with the QVR API to inject motion events with PIR sensors and motion events detected by other software.

The circle closes here, as I stumbled over motion again. motion is quite clumsy to configure. Looking for a configuration tool I found motioneye. Motioneye is a open source surveillance software based on motion. It has all the features I need and its motion detection is much more powerful and flexible than the one from QVR.

motioneye is a real OSS gem and replaced QVR Pro within 2 days… ๐Ÿ˜€

webcam rtsp stream multiple usage

Using the rtsp stream of webcams from multiple apps can make you some headache, i.e.
– WiFi connection bandwidth
– load on cam
– credential sharing

I solved these problems with an rtsp-proxy from

With this proxy, the stream from the cam is only transferred once from the cam to the proxy, independent of the actual apps connecting to the cam via proxy.

To use the proxy on my QNAP NAS (where I use QVR PRO) I wrote a Dockerfile: https://github.com/FotoFieber/live555-docker

On my debian server I built a Docker image and saved it to a tar-file on my nas (build.sh):

The saved image I then importet on my QNAP-NAS with

Point devices from minut.com with API troubles

When you buy IOT devices, that can only be accessed via cloud api, you have to think about

  • Internet connection problems
  • API changes
  • shut down of API

I have written an article on this topic some time ago:


Today the API problem hit me with my point devices from https://minut.com/

Inspite of the outdated API documentation at https://api.minut.com/draft1/docs/ (e.g. ambient light IR readings do not work), I managed to get temperature, humidity, barometer and soundlevel readings with a node-red flow. Today I got an eMail, that my traffic to the API is to high and they blocked my account.

Maybe it is time to hack the device as I did with my sonoff dual https://itead.freshdesk.com/support/discussions/topics/11000006870

improved cheap ntp stratum 1 server

Theย cheap stratum ntp serverย based on ESP8266 turned out as unstable. I’m not sure, if it is a hardware or a software problem.ย  The module suddenly hangs and then sometimes the watchdog is triggering and sometimes only a poweroff and poweronn will get the wifi connection up again. I had similar problems with my secure esp8266 sensor node. It seems, that the problems are more often with many data transmitted via serial interface.

I have adapted my arduino code to be used with an ESP32 and made a prototype with this platform. Time will show, if this solves all the stability problems.