This is the personal homepage of Daniel Friesel / derf / derfnull (depending on context and nickname availability). Every now and then, I write software and take pictures, which you can find here. There's also some hosted services.


Daily list of IC trains with Bimz wagons
Provides random music genres
Listen to Symphonic Punk



App::Raps2 v0.54
CLI password safe
Travel::Routing::DE::VRR v2.18
Interface to EFA-based itinerary services
> efa Essen Martinstr Düsseldorf Hbf
14:34 ab  Essen Martinstr.: Bstg. 1      Straßenbahn 108      Essen Altenessen Bf Schleife
14:38 an  Essen Hauptbahnhof: Bstg. 1

14:47 ab  Essen Hauptbahnhof: 2          R-Bahn RE11 (RRX)    Düsseldorf Hbf
15:24 an  Düsseldorf Hbf: 10
Travel::Status::DE::DBWagenreihung v0.02
Interface to Deutsche Bahn Wagon Order API
> db-wagenreihung 'Essen Hbf' 723
▏      G       ▕▏    F    ▕▏    E     ▕▏   D    ▕▏    C    ▕▏    B    ▕▏             A             ▕
     >  39   38    37   36   35   33   32   31    29   28   27   26   25    23   22   21 >
Travel::Status::DE::DeutscheBahn v2.04
Interface to HAFAS-based arrival/departure monitors
> hafas-m 'Messegelände, Leipzig'
14:32    STR   16  Lößnig, Leipzig
14:40    STR   16  Sportforum Süd, Leipzig
14:43    ALT   86  S-Bahnhof Messe, Leipzig
14:47    STR   16  Lößnig, Leipzig
> db-iris 'Dortmund Hbf'
14:38 +16  IC 2027     Passau Hbf            11
14:39      ABR RE11    Kassel-Wilhelmshöhe   8
14:41      RE 57       Winterberg(Westf)     2
└────      RE 57       Brilon Wald           2
14:41      S 5         Hagen Hbf             5
14:42      S 2         Dortmund Hbf          6
14:45 +1   RE 1        Aachen Hbf            16
> ura-m Talbot
14:49:41  52    Aachen Bushof
15:04:47  11    Lichtenbusch
15:05:00  52    Eschweiler Bushof
15:18:00  1     Aachen Bushof
15:19:56  11    Hoengen Markt
15:35:00  1     Schevenhütte
Travel::Status::DE::VRR v1.15
Interface to EFA-based departure monitors
> efa-m Dortmund 'Universität S'
08:32  +1  02  445    Dortmund Am Kai
08:35      3   HB1    Dortmund Technologiezentrum
08:36      3   HB1    Dortmund Eichlinghofen H-Bahn
08:38      02  447    Dortmund Bandelstraße
08:39      2   S1     Dortmund Hbf
08:40      01  447    Dortmund Hacheney
> ct a mutt
mutt: retrieving package
Cloning into 'mutt'...
created   .muttrc         -> /home/derf/packages/mutt/etc/muttrc
> ekgping ccc.de

Firmware and Hardware

RGB cat moodlight
I²C moodlight
VUSB-I²C v0.02
USB ↔ I²C adapter


These projects are neither developed nor maintained any more. Some do offer basic functionality, though.

App::Slackeria v0.12
Project status overview


Travel-Status-DE-IRIS-1.44.tar.gz (signature)

  • Add delay code 67 (Behördliche Anordnung). Patch by @marudor

Travel-Status-DE-IRIS-1.45.tar.gz (signature)

  • Provide properly versioned Stations.pm file

Travel-Status-DE-IRIS-1.43.tar.gz (signature)

  • db-iris: Correctly set cache expiry. In 1.42, backend replies were cached indefinitely due to a typo

Travel-Status-DE-IRIS-1.42.tar.gz (signature)

  • Result: Fix TO_JSON method
  • db-iris: Cache backend results by default
  • db-iris: New options: --json and --no-cache

Travel-Status-DE-IRIS-1.41.tar.gz (signature)

  • Result: Add wing_of accessor
  • Follow name and DS100 change of Freiburg West (RFW) to Freiburg-Landwasser (RFLW)
  • Add more stations

Travel-Status-DE-IRIS-1.40.tar.gz (signature)

  • Incorporate the last few years' worth of station name changes

Travel-Status-DE-IRIS-1.39.tar.gz (signature)

  • Add missing geocoordinates to nearly all remaining stations (thanks to @marudor)
  • Add stations opened this year (thanks to @marudor)

Travel-Status-DE-IRIS-1.38.tar.gz (signature)

  • Add geocoordinates for belgian stations (patch by @Knuspel)
  • New IRIS option: keep_transfers

Travel-Status-DE-IRIS-1.37.tar.gz (signature)

  • Add geocoordinates for french stations served by Thalys/TGV (patch by Florian Wurzel)

Travel-Status-DE-IRIS-1.36.tar.gz (signature)

  • Update stations list, prune duplicates and outdated entries (251 additions, 155 deletions). Incorporates patches by Moritz Schlarb and @Knuspel -- Thanks!
  • Update documentation to reflect that EVA IDs used by DB IRIS are not the same as UIC station IDs (they just happen to be identical in 99% of cases)
  • Stations are now stored in share/stations.json. See README.md for station management hints.

Travel-Status-DE-IRIS-1.35.tar.gz (signature)

  • Add additional dutch and austrian stations (thanks to @Knuspel)
  • Add geocoordinates for several of those (thanks to @Knuspel)

Travel-Status-DE-IRIS-1.34.tar.gz (signature)

  • Improve request speed when using with_related by ignoring subway stations which do not have results anyways (e.g. in Hannover Hbf)
  • Do not forward unexpected IRIS message codes (ID ≥ 100) to the user
  • IRIS: Add ->related_stations accessor

Travel-Status-DE-IRIS-1.33.tar.gz (signature)

  • Fix $result->route_pre / route_post accessors providing bogus data when all previous/following stops are cancelled. They used to return sched_route_pre / sched_route_post instead of an empty list in this case.

“Deep Sleep” allows an ESP8266 microcontroller to enter a very low-power sleep mode with less than 1mA sleep current. It works by connecting GPIO16 (which can be controlled from deep sleep) to the reset pin (RST) and programming the ESP8266 to provide a falling edge on GPIO16 after a specific amount of time, causing a system reset and thus a wakeup.

Here is how to use it on an ESP8266 controller (e.g. NodeMCU board or Wemos D1 mini) running the NodeMCU Lua firmware:

  • Connect pin D0 (ESP8266 GPIO16) to RST (ESP8266 reset). Note that as long as D0 and RST are connected, you need to manually push the reset button when uploading new firmware using esptool – if that's too much of a hassle, consider using a jumper or another kind of reversible connection. Uploading NodeMCU applications is not affected by this, as it relies entirely on in-band signaling via UART.
  • Do not use any GPIO functions operating on pin D0.
  • Call rtctime.dsleep to go to sleep. When the sleep time has elapsed, execution will not continue normally -- instead, the ESP8266 will be reset and start over.
  • You might also be able to use node.dsleep

Travel-Status-DE-IRIS-1.32.tar.gz (signature)

  • Travel::Status::DE::IRIS::Stations: Add geocoordinates fo some swiss and austrian stations

Travel-Status-DE-IRIS-1.31.tar.gz (signature)

  • Travel::Status::DE::IRIS::Stations: Add EVA/UIC station numbers and use full names for non-german stations.

Travel-Status-DE-IRIS-1.30.tar.gz (signature)

  • Result: Add ->station and ->station_uic accessors. These are useful to determine which station an individual train belongs to when requesting departures of multiple stations at once using the with_related option.

Travel-Status-DE-IRIS-1.29.tar.gz (signature)

  • Add QoS code 72 (no info/entertainment system available)
  • Fix erroneous QoS codes 83, 91, 92