Upcoming v3 of Open Hardware miniPCIe WWAN modem USB breakout board

Back in October 2016 I designed a small open hardware breakout board for WWAN modems in mPCIe form-factor. I was thinking some other people might be interested in this, and indeed, the first manufacturing batch is already sold out by now.

Instead of ordering more of the old (v2) design, I decided to do some improvements in the next version:

add mounting holes so the PCB can be mounted via M3 screws

add U.FL and SMA sockets, so the modems are connected via a short U.FL to U.FL cable, and external antennas or other RF components can be attached via SMA. This provides strain relief for the...

Osmocom - personal thoughts

As I just wrote in my post about TelcoSecDay, I sometimes worry about the choices I made with Osmocom, particularly when I see all the great stuff people doing in fields that I previously was working in, such as applied IT security as well as Linux Kernel development.

When people like Dieter, Holger and I started to play with what later became OpenBSC, it was just for fun. A challenge to master. A closed world to break open and which to attack with the tools, the mindset and the values that we brought with us.

Later, Holger and I started to do freelance development for commercial users...

Returning from TelcoSecDay 2017 / General Musings

I'm just on my way back from the Telecom Security Day 2017 <https://www.troopers.de/troopers17/telco-sec-day/>, which is an invitation-only event about telecom security issues hosted by ERNW back-to-back with their Troopers 2017 <https://www.troopers.de/troopers17/> conference.

I've been presenting at TelcoSecDay in previous years and hence was again invited to join (as attendee). The event has really gained quite some traction. Where early on you could find lots of IT security / hacker crowds, the number of participants from the operator (and to smaller extent also equipment maker) industry has been growing.

The quality of talks was great, and I enjoyed meeting various familiar faces. It's just a pity that it's only...

Magical Black Bean - Infrared control over WiFi/3G/4G

Few weeks ago I've received the Broadlink RM mini 3 Black Bean Smart Home Wifi  Universal IR and I've took some time to test it before I can give more details. 
Is absolutely fantastic ! 
As features:
-I was able to record any remote I had around -I was able to connect to it from WiFi or 4G from my mobile -I was able to make scenes for multiple remotes. 
The scenes part is very handy since allows me to control multiple devices with one touch. For example:
-start TV
-wait 1 sec
-start Set-box
-wait 1 sec
-put TV on HDMI 3 input
-change SetBox to channel 5.
-start amplifier
All of that...

VMware becomes gold member of Linux Foundation: And what about the GPL?

As we can read in recent news, VMware has become a gold member of the Linux foundation. That causes - to say the least - very mixed feelings to me.

One thing to keep in mind: The Linux Foundation is an industry association, it exists to act in the joint interest of it's paying members. It is not a charity, and it does not act for the public good. I know and respect that, while some people sometimes appear to be confused about its function.

However, allowing an entity like VMware to join, despite their many years long disrespect for the most basic principles of the...

Gory details of USIM authentication sequence numbers

I always though I understood UMTS AKA (authentication and key agreement), including the re-synchronization procedure. It's been years since I wrote tools like osmo-sim-auth which you can use to perform UMTS AKA with a SIM card inserted into a PC reader, i.e. simulate what happens between the AUC (authentication center) in a network and the USIM card.

However, it is only now as the sysmocom team works on 3G support of the dedicated OsmoHLR (outside of OsmoNITB!), that I seem to understand all the nasty little details.

I always thought for re-synchronization it is sufficient to simply increment the SQN (sequence number). It turns out, it isn't as...

www.apertus.org: apertus° accepted for Google Summer of Code 2017

We are very proud to announce that apertus° has been accepted as a new mentoring organization for this year’s Google Summer of Code (GSoC). As only a small number of new organizations are allowed to join each year and the majority already in the program have been participating for many years, this is especially exciting. For anyone not familiar, GSoC is a program where students are paid to contribute to selected open source projects between June and August.

Field Programmable Gate Arrays (FPGAs) and their embedded systems are...

GTA04 project halts GTA04A5 due to OMAP3 PoP soldering issues

For those of you who don't know what the tinkerphones/OpenPhoenux GTA04 is: It is a 'professional hobbyist' hardware project (with at least public schematics, even if not open hardware in the sense that editable schematics and PCB design files are published) creating updated mainboards that can be used to upgrade Openmoko phones. They fit into the same enclosure and can use the same display/speaker/microphone.

What the GTA04 guys have been doing for many years is close to a miracle anyway: Trying to build a modern-day smartphone in low quantities, using off-the-shelf components available in those low quantities, and without a large company with its associated financial backing.

Smartphones...

Diodes part 3: a working diode steering circuit

I've made something interesting with my aluminium and soda bicarb diodes: a 7-segment display encoder. Also includes instructions on how to make your own.

Kalman filter

In few projects I've needed the Kalman filter to suppress the noise and other inaccuracies especially from accelerometers. Below is a nice picture from a live stream of data transmitted by the ESP8266 LDR over websockets to an application server written in javascript. The data received in the browser looks like:
With red is raw data and with white is the predicted data after the Kalman filter was applied.