Archive for category Hardware

FriendlyELEC NanoPi NEO Plus2

NanoPi NEO Plus2 is a brand new board released by FriendlyELEC. It’s slightly bigger than the NEO2 board, and packed with much more cool stuff: 1GB RAM, Wifi+Bluetooth module, and 8GB eMMC chip. It has also two USB2.0 port connected to independent USB controllers.

The NanoPi NEO Plus2 Basic Kit accompanies the board with an acrylic enclosure, and the first orders are delivered with an UART USB adapter. They also listed an antenna, but I did not receive it in my kit. Anyway I have a better option, a flat self-adhesive antenna like this one.

The acrylic enclosure is about two times thicker than that for NEO boards, and it also has a hole for antenna mount. I added 8 pieces of M2.5 washers and 4 M3 pillars to the original design, to make it more long-lasting. The photo below has the UART adapter plugged in.


Armbian still needs some work to be done to support this new board. But the Ubuntu image that is available from FriendlyELEC is quite enough to demonstrate all the hardware capabilities. Unlike Armbian, it does not mount /tmp and /var/log as tmpfs, so the SD card may experience a faster wearing.

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Best Android tablet for little children

Our good old Samsung Galaxy Tab 3 7.0 Kids Tablet has finally died after over 3 years of everyday heavy use, so I needed a new solution. So far, here is the best combination that I could find:

This silicon case for Samsung Galaxy TAB A 7″ SM-T280 is a solid and protective piece, and it allows the kids hold the tablet with their little hands without slipping off. It also works as a stand, so it’s very convenient for watching videos.

The Samsung Galaxy Tab A (7″, 8GB, Metallic Black) fits perfectly into the protective case. The tablet is coming with preinstalled “Kids Mode” application, which is pretty neat, but very restrictive: the kid can watch only the videos on SD card that you mark as safe, and YouTube is not available. You can install kid-safe YouTube wrappers from the Play market, but it’s a bit too much hassle to my taste.

So, instead of the Samsung Kids Mode, I installed Kids Place by kiddoware. With a little payment, you get a good child protection mode, and you can enable YouTube directly on the child screen. The payment is also transferable to other devices under your account.

Also, this portable Bluetooth speaker works as a stand for a tablet, and it produces a much better sound than the tablet’s own speaker. Unfortunately the silicon case is too thick for this stand, but it’s a minor issue, and the speaker can easily be placed behind the tablet.


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Linux reboot freezes on Acer Aspire One

I needed to install CentOS 6 on one an old Acer Aspire One notebook (with Intel Atom CPU) for some software testing. The problem is, that it could not perform a reboot, and I needed to press the power button every time. These instructions for reboot=X parameter for kernel did not help at all.

What really helped, is `kernel-ml` package from repositories. At the moment of writing, it was version `4.0.0-1.el6.elrepo.x86_64`.

Keep in mind that after installing kernnel-ml package, you need to edit /etc/grub.conf and make this new kernel as default. No additional boot options are required.

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mSATA drives for PC Engines APU

Drives with problems:

  1. KingSpec 16GB (Model Number: KingSpec KSM-mSATA.7i-016MJ, Firmware Revision:  SVN454): quite often, the kernel times out to boot at the start.
  2. SuperSSpeed S238: with the old firmware, TRIM operation erased the boot sector. The newer firmware disables TRIM.

Drives without problems (everything works fine with TRIM)

  1. MyDigitalSSD Super Boot Drive (Model Number:  SB mSATA SSD, Firmware Revision: S9FM01.8)
  2. SanDisk X110 (Model Number: SanDisk SD6SF1M032G1022I, Firmware Revision: X231200)
  3. Kingston Now (Model Number: KINGSTON SMS200S330G, Firmware Revision: 524ABBF0)

The testing procedure is quite simple: a background process is massively creating and deleting a small file, and another process calls fstrim every few seconds. Then the health of the filesystem is checked after an hour or so.

while true; do echo xxxxxxxxxxxxxxxxxxxxxxxx >xxx; done &
while true; do fstrim -v /; sleep 10; done



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Baby stuff

here’s a list of our stuff, might be useful for new parents:

  1. Stokke Tripp Trapp chair with Newborn Set: a must with more than one kid, and very useful with one too.
  2. Stokke My Carrier: quite useful, although it’s still not the full freedom that you want
  3. Red Castle Babynomade blanket: very useful, available in two variations(winter and summer), Size 2 is recommended from the beginning — the baby is not lost in it, and you have it useful for longer time
  4. C&A sells baby bodysuits, CHF 12 for 5 pieces, with only small funny graphics and no Disney. Excellent price and quality, sizes available for the first 12 months.
  5. Bebeconfort Amplitude changing table.  Most of changing tables are too low, and your back will hurt very soon. This one is adjustable and can be brought up to the waist  level of a basketball player.
  6. Stokke Bounce ‘n’ Sleep Daybed: very convenient to carry the child around your apartment and let them sleep beside you.
  7. Red Castle Cocoonababy: lets your newborn sleep in the most convenient position, and it also passes perfectly into the Stokke daybed.
  8. Philips Avent SCD 525/00 DECT: a perfect babyphone, works like charm, convenient and long-lasting. The base station can be powered by normal or rechargeable AA batteries (normal Alkaline batteries will last for few weeks).

Also for twins:

  1. TFK Twinner Twist Duo is so far the best twin stroller that we tested. It passes in every standard door, and very easy to handle. It also has a mounting option for baby car seats, but this construct becomes bulky and does not pass most of doors and lifts.
  2. the Pro Baby shop has 15% discount on twin purchases

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FreeSWITCH performance test on AMD Geode LX800

This is a proof-of-concept test to see if the PC Engines’ ALIX2 board is suitable for a basic VoIP application.

First I compiled the latest FreeSWITCH version from Git. It was a mistake to run the compilation on the ALIX board: the CPU is quite slow, and the whole compilation took several hours.  I should’ve done the compilation on a more powerful machine and then copy the binaries to the ALIX.

In these tests, I used the default dialplan that came with FreeSWITCH (highly insecure, with the password 1234 for all users). I added an external SIP profile to connect it to my other IP PBX, so that I can easily place incoming calls.

An Ubuntu notebook with Twinkle was used as the SIP client for the ALIX server.

FreeSWITCH was running with -rp option, assigning the process a high priority.

1. IVR prompts and voicemail worked immediately, and the flash memory speed delays were insignificant.

2. A call without transcoding. Both call legs were using PCMA codec:

# "vmstat 1" output:
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
1  0   3792   4036  23204 187060    0    0     0    36 1205 1576  0  2 98  0
1  0   3792   4036  23204 187068    0    0     0     0 1205 1548  0  3 97  0

# "top" output
3187 freeswit  -2 -10 30504  12m 4148 S  6.9  5.0   0:16.60 freeswitch

3. A call with transcoding. One leg used G722@16000 codec, and the other leg was GSM@8000:

# "vmstat 1" output:
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 1  0   3796   4320  22844 186712    0    0     0     0 1207 1333 14  3 83  0
 1  0   3796   4320  22844 186712    0    0     0     0 1205 1348 14  4 82  0

# "top" output:
  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND            
 2909 freeswit  -2 -10 31240  12m 4188 S 21.3  5.1   1:18.38 freeswitch

4. A conference with 5 PCMA channels:

# "vmstat 1" output:
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 0  0      0 122888  36440  58244    0    0     0     0 1458  844  7  6 87  0
 0  0      0 122896  36440  58244    0    0     0     0 1440  814  6  4 90  0

# "top" output:
  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND            
 8124 freeswit  -2 -10 34208  13m 4224 S 12.1  5.5   1:29.85 freeswitch

Outcome: it’s possible to build a pretty decent small PBX for SOHO usage with this hardware. In all cases the voice quality was absolutely fine.

UPD1: a conference call with automatic recording into MP3: the CPU load jumps to 60% every few seconds, and the conference experiences significant delays and clippings. With WAV recording, everything runs smoothly, and not much different from the above results.

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Medion/Thalia OYO E-Book Reader

Bought the OYO reader few months ago, and here’s the summary.

It’s cheap: most probably, subsidized by the Thalia book store. It also allows you to copy books via USB or read them directly from a Micr0SD card.

It’s German: the UI at the first run is all in German language, but you can switch to English in settings.

It’s slow… sometimes you have to wait for its reaction. Sometimes it hangs up on large PDF files.

It’s buggy. Also Medion is not really a software business, so all the customer relation and software development is new to them.

The newest firmware R3407 is reported to have problems with PDF files, and also many people could not switch off the device or put it into standby mode.

Bugs found with firmware R2342:

  • Russian ePub files are a bit of a problem: symbols in italics are displayed as question marks. HTML and PDF files are displayed as expected
  • I couldn’t fix it in Landscape mode. Orientation settings provide 3 options: Auto, Portrait, Landscape. Landscape appears to be equal to Auto: the device is sensitive to its gravity sensor, and tries to re-draw the text as you move around.
  • It doesn’t remember the PDF reading settings, and you have to choose them next time you open a PDF.

Useful links:

  • Michaels EDV-Blog (in German). Interesting news and test results. Saved me a bit of time in not upgrading to R3407.
  • Frank’s Wiki (in English). The guy has hacked the device. You can, in theory, run your own software with it 🙂
  • OYO on Facebook (in German). The official facebook page, with all announcements from the software developers and user forum.



Cybook Orizon reader seems to be quite nice…


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