New BMPCC4K firmware

Project history

  1. Previous project: LPG/CNG Price Reporter
  2. last step: Mysterious crash
  3. current posting
  4. next step: Mysterious crash
  5. Next project: none

Looks like there is a new camera firmware for the Blackmagic Pocket Cinema Camera 4K.

Since the Bluetooth protocol I used to write my "BMPCC4K Camera Control" Android app did not support some features of this camera yet. I'll give it a try and see what has improved....

Stay tuned!

Stable Releases:

Open Beta Test: (early access to improvements)


New phone - Blackview BV9600 Pro

Actually I wanted the Blackview 9600 Plus (fingerprint reader in the screen) and backed the Kickstarter compaign.
But that was stopped and I was given the choice of getting a BV 9600 Pro or a BV9700 Pro (Much smaller battery, smaller display, IPS instead of Amoled, higher clocked CPU).

I have chosen the BV 9600 Pro.
It shipped with an Android 8.1 image  ("BV9600Pro_S70_V1.1_20181105V31").
For all software issues. That's the firmware I'm talking about.


  • Battery runtime is as advertised. Without SIM card after 24h intense use (reinstalling 140 apps) and sleep tracking, it was still at 50% 
  • At some point it is supposed to get an Android 9.0 or 9.1 update.
  • It has working Qi wireless charging (lacking on my previous phone).
  • It has the same 12V 1.5A and 9V 2A quick charge as my previous phone.
  • It has NFC (also lacking on my previous phone).
  • It's a roughed IP68 outdoor phone and even compes with a hook to attach a strap for not loosing it. So it needs no Otterbox or other case.
  • SIM card can be removed without any special needle or other tools and without disassembling any case.
  • Bluetooth Audio with my Renault/Dacia MediaNav works agian (failed on the last 2 generations of phones I had)
  • The supplied contacts app is not limited to only create contacts in the address book of the first of 2 Google accounts.


  • The socket IS NOT USB-C. It's requires special 8mm plugs and standard 5mm USB-C cables don't fit!!! Obviously this is a MAJOR, MAJOR issue!!!
  • The menu/overview -button (square)  DOESN'T WORK. You can't switch between apps with the stock or any 3rd party launcher.
  • The Android Multi-User feature has been disabled (present since Android 4.4) .
  • It comes with a screen protector that is very hard to attach because of the raised display bezel. 
  • After 2 days I still can't post in the Blackview User Forum to find a solution about any of my software issues. The first post of any new user must be vetted by an admin and that still hasn't happened.
  • Some system menus have translation errors. Others are hard to understand after translation into German or UK English or US English
  • The supplied phone app is in no way integrated with the supplied contact app. A phone number can not be added to an existing contact and a contact has no long-press menu to open them for editing.


  • Back and Menu are reversed compared to my last phone
  • The default icons (including all settings items) and the wireless charger are a terribly over-the-top super-bling rose-golden colour.


Parametric wire dispenser

At the moment Youmagine is pretty much broken in Firefox and in Chrome due to the choice of company they got their SSL certificate from.

However I still published a new accessory for my soldering workspace.
A simple wire dispenser that with parameters for the number and size of spools.


Mysterious crash

Project history

  1. Previous project: LPG/CNG Price Reporter
  2. last step: Android App for Blackmagic Pocket Cinema Camera 4K
  3. current posting
  4. next step: New BMPCC4K firmware
  5. Next project: designing a chain link tool library

The BMPC4K app I wrote has exactly 1 crash on 2 devices in Play Store.
However I'm completely puzzled by the stacktrace.
It's not made easier by the fact that I can't reproduct the crash since it happens on 2 user's phones that I have no access to.

All my own code is in the biz.wolschon... -packages.
This crash is entirely in the Wear OS library by Google.
I'm using
implementation 'com.google.android.gms:play-services-wearable:16.0.1'

16.0.1 is indeed the latest and greatest version available at this time.
Since Google has obfuscated it's libraries, a search for other people with this issue in that line of code turns up nothing.

It seems to happen at Fragment -creation time. However I'm not using any fragments from GMS. At least I'm not aware of any.
All I can try is to move from the support library 27.1.1 to 28.0.0 with a 28 target SDK. This mandates some unrelated changes. None of them look like they should affect me.

Update: I just came back, tested that the new, public beta version works and uploaded it to Play Store. Let's see if the crash still happens and if so, something shows up in the Stacktrace that hints to a cause this time.



LPG Preismelder Android app updated again

Project history

  1. Previous project: none
  2. last step: LPG Preismelder Android app updated
  3. current posting
  4. next step: none
  5. Next project: Android App for Blackmagic Pocket Cinema Camera 4K

Android 9 will no longer allow unencrypted HTTP communication.
So I had to pull out my old "LPG Preismelder" fuel station app for GPL and CNG fuel stations in Europe.
It is a simple app. It still works fine.
However nowadays Google Play Store no longer allows the old target SDK
and Android Studio does't like the old Build Tools.
So I had to update them and consequently add support for permissions that are no longer granted at download-time.
Also the Google Maps API has changed a lot and it is no longer possible to just ask the Map-Fragment for the map and perform updates (e.g. set the location). All this now has to be done asynchronously.

This did introduce a small number of crashes for rare cases, thus ruining my "max 1 crash per year at 1000 users" record.


  • App on Google Play


Rotacy CNC: That damn earthing again

Project history

  1. Previous project: TravelCNC
  2. previous step: Problem with optical input switches
  3. current posting
  4. next step
  5. Next project: designing a chain link tool library

When I assembled my newest DIY CNC mill on a piece of wooden OSB board... what could you possibly forget?
Wood is not conductive.

Everyhing is build super clean.
Crimped using the proper tools.
Signal power and signal ground distributed using proper DIN rail blocks.
Stepper drivers stronger then the actual power supply, steppers and forces needed.
Strangely enough I machined an entire part in perfect finish for a week before any issues showed up.
Then the A axis stepper starting moving on it's own and jittering. But only it it had already moved before. Not related to the spindle running or not.

Problem 1: wrong power supply

I had way too much power provided to my stepper drivers.
48V supply because the drivers where advertises as 8-50V input voltage.
Actually however where 8-42V with 50V being the absolute maximum rating.
The dealer overstated the capabilities of the driver.

Problem 2: Earthing

This did not solve my problem.
It needed a borrowed oscilloscope to figure out that I simply forgot to connect my giant A-axis gear box, sitting on the OSB base-plate to PE.
The power supplies (not the spindle) for the strong steppers seem to radiate a ton of EMI into the huge metal block that is the A axis. Static buildup from the gears inside and from machining plastic for days on end surely did not help either.
Since the power flowing from the motor to the motor driver caused the "work" LED on the driver to blink, I searched for hours where the supposed stray inputs to the driver came from. Not realizing that this came from the output of the drivers and not the inputs.

I had the same issues already with my Chinese 6040 CNC (all Aluminium but designed with no regard to earthing large metal parts and thus the steppers they connect to).
Seems I had to learn that lesson again.

Parts used


Rant about the 8Sinn cage for the BMPCC4K

I just wrote the following feedback to the very expensive 8Sinn cage for the Blackmagic Pocket Cinema Camera 4K:

I have your Blackmagic Pocket Cinema Camera 4K -cage.
There are 3 features you should definately improve:

1: Access to the locking power socket is nearly inpossible.
Getting your fingers in there is a nightmare even without fighting the cover doors.

2: The cable strain-relieve for the USB-port does not open wide enough to allow
the cable that comes with the Samsung T5 to fit and the expensive Samsung T5
holder did not come with a cable that does.

3: The allen key(s) has no place to store it in the cage itselt.
So it's always missing.
I can't mount my T5 SSD becaue I only have the caged camera with me.
The cable stress relieve on the T5-holder can not be opened without
and it's comes tighened from the factory.
This step should be possible, if not trivial, without easy-to-loose tools.
What's the point of having nice, machined handles if you need an allen
key anyway?
At the very least a laser-marking what size of tool one needs to send
someone to buy for the next day of shooting would have helped.

The cage uses 2 sizes of allen key.
However the SSD holder uses a THIRD size for no obvious reason.
The smaller size, already used in the cage looks like it would have worked just fine
without adding an additional, easy to loose, tool to the mix.

A second hot shoe (maybe as part of the SSD-holder) would be nice,
so I can mount my microphone while having the SSD semi-permanently attached.
(Of cause I can screw in an additional hot shoe. But it would have been nice if this
was something that just works out of the box.)


Android App for Blackmagic Pocket Cinema Camera 4K

Project history 

  1. Previous project: LPG/CNG Price Reporter
  2. last step: none
  3. current posting
  4. next step: Mysterious crash
  5. Next project: none


Minimal start screen while recording...
...while idle...

...and before a connected to a camera.
Very early version of the focus slider.

Android Wear smartwatch.
Selection of some settings values.


I've just written an Android app that is capable of starting and stopping a recording on the Blackmagic Pocket Cinema Camera 4K  (BMPCC4K) and the
URSA Mini Pro (no wireless focus supports on the EF mount version) as well as the
URSA Mini Broadcast.

It can
  • Start/Stop a recording remotely
  • Start and Stop using an Android Wear smartwatch (for Vloggers)
  • display a live timecode, remaining time on storage medium and the most important parameters
  • pull wireless live focus and zoom via touchscreen
  • store and recall 3 combinations of focus and zoom with a smooth transition
  • change parameters - codec, resolution and frame rate (some values not offered yet)
  • edit metadata

I am still adding features.
I plan to
  1. allow syncing the GPS-time of the phone to the camera(s)
  2. allow to start/stop recording on multiple cameras e.g. for multicam interviews. (No idea for a good user interface yet. Proposals?)
  3. Support the Panasonic GH5 / GH4R / GH4 camera via Wifi in addition to Blackmagic cameras via Bluetooth Low Energy
Limitations beyond my control:
  • My idea to also display audio meters will not work because the camera does not seem to send these via Bluetooth.
  • DCI 4K and 4.6K resolutions can not be selected because Blackmagic forgot to define the values in the protocol 
    • Support ticket DEV-144. These will be fixed in a future firmware.
  • Also the camera does not seem to report the selected storage medium correctly.
    • I'm getting a small CFast card to experiment with this.

Stable Releases:

Open Beta Test: (early access to improvements)


Yes, I did put a reasonable price tag of 10€ on it.
That's 20% the price of a power-cable set or 14% of an original Canon-battery or a meal at McDonalds.
Sales tax gets 19% of the shown price (depending on the country) and Google a cut of 30%. So it's just about 6,30€ that actually end up in my pocket to pay for small expenses.

Privacy Policy

(This is required by Google Play Store.)

This app does not collect, use or distribute any kind of personal data.
End of story.


version "1.2.21" (07.02.2019)

  •  Tested with Firmware 6.1. Sadly Blackmagic still did not add "DCI 4K" and"4.6K" as selectable resolutions
  • Support for lenses with no aperture control by the camera.

version "1.2.19" (28.12.2018)

  • Minor fix with the record start/stop command to be compatible with more strict Blackmagic camera firmwares.
  • Fixed white on white text for dialog buttons in Android 8
  • Aperture and shutter angle can be controlled
  • Only slots with a card in it can be selected
  • Better fit for slim displays
  • Settings become 2 screens to be less cluttered


  • I finally figured out what I did wrong in decoding f-stop values. Aperture control is coming after the holidays.

Version "1.2.13" (17.12.2018)

  •  Can display and change active storage card


  • On this day I'll hopefully see the very first money from the November sales in Google Play Store. It should actually pay for 35% of my Samsung T5 SSD (without the cage mount) practically required to do anything useful with this camera. The 30% cut for Google after the 19% cut for sales tax is quite heavy. Given my actual hourly wage this side project will never turn any profit in a hundred years but that's okay. It's fun.

Version "1.2.11" (10.12.2018)

  • For Some reason Play Store shows this version as "1.2.1" instead of "1.2.11".
  • I manually fixed the old name still shown in Play Store.
  • Fixed crash on k6000 Plus (Android 8.0) for Bluetooth device with no name
  • Unknown camera models can be reported for addition via email

Version "1.2.10" (6.12.2018)

  • Fixed crash on Pixel 2 (Android 9) when aborting a scan for bluetooth devices in range
  • Nicer display of remaining time on storage medium
  • >M-rate framerates selectable (29.97,...)

Version "1.2.7" (24.11.2018)

  • Yes, on the same day as the earlier 1.2.6.
  • Reverse engineered the storage-related broadcasts. It now displays the remaining time on card slot II.
  • I'm trying to get my hands on a CFast card to try card slot I.

Version "1.2.6" (24.11.2018)

  • I got a new icon drawn by a facebook user. Thanks a lot!!!
  • I also changed the name from "BMPCC4K Record Button" to "BMPCC4K Control" because the app does so much more nowadays"
  • I was able to add entering metadata.

Version "1.2.4" (20.11.2018)

  • Power zoom rocker and a zoom slider added.
  • Also you can store and recall 3 focus+zoom positions now.

Version "1.2.1" (15.11.2018)

  • Yes, on the same day as the earlier 1.2.0.
  • Wireless follow focus slider added.

Version "1.1.1" (13.11.2018)

  • Huge improvements to my Bluetooth Low Energy stage-engine. Searching for the camera(s) is MUCH faster now

Version "1.0.4" (12.11.2018)

  • I figured out how to detect someone on the camera starting a recording instead of starting it via the app (and by extension the case of a recording already running when the app is started).