My visit at the Easterhegg 2014 in Stuttgart, Germany

Interesting things I've learned at the Easterhegg in Stuggart. I've been there Saturday and Sunday only.

Day 2

  • dawanda used cross device responsive tables
  • Better presentations with a workshop by Dirk Haun. We heard about the Rule of Thirds, no bullet points, images from http://freeimages.com, http://www.flickr.com/creativecommons/, ...
  • ImageMagick can create 3D software boxes from images.
  • Adafruit sells LED strips that can be used by Arduino easily
  • palava.tv uses WebRTC and an open source central signaling server to enable peer to peer (P2P) video and audio chats and conferences. Soon the server might be available in an SD card image for the Raspberry Pi.

Day 3

  • AYAB - all yarns are beautiful: Project to connect old Brother KH-910 and KH-930 knitting machines to computers to knit images of 200px width (and arbitrary height). Project located in Munich (MuCCC). Uses Arduino, Python, and (future work) PyQt. https://wiki.muc.ccc.de/ayab, http://www.ayab-knitting.com/
  • A few ideas about CNC machining, e.g. Shapeoko, importance of good common ground, ...
  • Spice up your presentations with reveal.js (e.g. http://palavatv.github.io/talk-webmontag/)and use Unicode characters, e.g. for :poop:. See fileformat.info for a detailed list. I have to learn about Emojis/Gemojis...
  • The version of a framework used in Java can be obtained by analysing its stack trace, especially the classname together with the line numbers. Maybe you should take care that your web server never prints that trace in case of errors.
  • Do not accept jobs that force you to make overtime hours that will be lost at the end of the month.
  • Baozi might be interesting to cook myself. Didn't have the time to go to the workshop.
  • A few introducery things about CAN and CANopen.
  • DMX, the protocol used for event technology (Veranstaltungstechnik) is very simple and can be used from Arduino, too. Maybe script a few cool effects using DMX isn't very hard. Just send a reset, a NULL, a node id and a value between 0 and 511 and your light starts to shine proportional - http://eh14.easterhegg.eu/pages/fahrplan/events/5772.html
  • A few very interesting details about how to sell your own electronics.
  • Weller PU 81 soldering stations are very expensive
  • There are quadrocopters that can carry 4kg

Half-height SD cards

Most SD cards seem to have only half of the plastic housing filled with electronics. If you need a half-height SD card, e.g. such that it does not stick out of a notebook too much, you can simply cut the SD card in half. Before doing this, take a very bright LED (e.g. from your mobile) to shine through the plastic and see whether there is really no electronics in this half of the SD card. Then open the housing carefully. If it's really empty, you can cut it off.

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HP8500A Paper Jam Mystery

This weekend I tried to repair a Hewlett Packard 8500A printer, 2 month after the 2 years guarantee was over. The display showed "Paper jam" error messages each time the printer was booted, which was a false error.

As it turned out, the problem was a broken cog, as can be found very often in your prefered search engine.

There are other images and videos online, e.g.

or

These are the images of my broken HP8500A after removal of the black plastic housing around the broken white cog:

Overview 1:

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Come closer to the broken cog:

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The removed plastic housing:

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And here we have the broken cog:

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I tried to glue the cog, but with no success. It seems the printer cannot be fixed.

Dump ATMEGA32 on AVR-NET board using avrdude

Using the ArduinoISP program on the Arduino (actually I used the Diavolino) one can dump the flash memory of the ATMEGA32 on the AVR-NET-IO from Pollin like this:

  1. Program ArduinoISP to your Arduino
  2. Wire up like this:pollin_avrnetio
  3. Open CMD. Go to your avrdude directory within the Arduino IDE and execute avrdude. Maybe you have to adapt the -P parameter to the serial port you are using to connect to Arduino.
cd "C:\Program Files (x86)\Arduino\hardware\tools\avr"
bin\avrdude -C etc\avrdude.conf  -c avrisp  -p ATMEGA32 -P com4 -b 19200 -U flash:r:C:\TEMP\flash_v103_pollin.bin:r

Your output look like this:

C:\Program Files (x86)\Arduino\hardware\tools\avr>bin\avrdude -C etc\avrdude.conf  -c avrisp  -p ATMEGA32 -P com4 -b 19200 -U flash:r:C:\docs\AVR-NET\flash_v103_pollin.bin:r

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.10s

avrdude: Device signature = 0x1e9502
avrdude: current erase-rewrite cycle count is -1062731548 (if being tracked)
avrdude: reading flash memory:

Reading | ################################################## | 100% 27.89s

avrdude: writing output file "C:\docs\AVR-NET\flash_v103_pollin.bin"

avrdude: safemode: Fuses OK

avrdude done.  Thank you.

The md5sum of the dumped flash memory image is

$ md5sum flash_v103_pollin.bin
4d040732d01c6aa88ec2dad4ddf56dea *flash_v103_pollin.bin