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In mijn vrije tijd werk ik aan leuke hobbyprojecten als deze. (die ik ook open source maak)Een 7 GHz prescaler voor RF-toepassingen en frequentiemetingen/tellers. (versie 2)Aangezien de frequentietellers met lagere prijzen een beperkte bandbreedte/snelheid hebben, moeten we deze prescaler toevoegen om de klus te klaren.Het bevat een OLED-display, een AVR-microprocessor en een HMC983LP5E van ADI om het HF-gedeelte te doen.Met behulp van de MCU (328PB) kunnen we een willekeurige verdeler ratio selecteren. (over SPI-interface)Met behulp van een D flip-flop van post scaler kunnen we er zeker van zijn dat de duty cycle 50% is. (Dit was een probleem in versie 1)Ik ontwerp/maak dit omdat mijn radio-amateur-vriendjes het nodig hebben.Ik werk/speel niet op deze hoge banden, maar dit is leuk.Het ontwerp van het schema en de layout is gedaan met KiCAD, simulatie met LT-spice. Software met behulp van GCC (gewone c-code)Behuizingsontwerp wordt met Fusion360 gedaan, gefreesd uit aluminium op mijn e…
Recente berichten

#oetelx #vlog HomTom HT50 LiPO hack, external battery

oetelx raw 4 : eerste test HBM compressor. Werkt niet.

oetelx raw 3 Ubuntu 20.4.1 Focal Fossa torrent download and install ESP32

Shapeways prints nice housings in a few days, happy client

I ordered these things on a Wednesday and now 6 days later I can assemble my product. This is how fast the world moves today. I designed the things in Fusion360 exported the STL files and sent the data to the Shapeways website. That was the whole proces.
They are really nice and fit precisely. I am very happy with this. #oetelx ahead of the curve.

TransIP nameserver change (how to update your linux Ubuntu VM/VPS)

NOTE TO SELF: change DNS on TransIP VPS machines.

Today I got an email from TransIP.Nameservers are changed. Please update your virtual machine.Old info :,, 2a01:7c8:a::c53, 2a01:7c8:b::c53New info is :
2a01:7c8:7000:195::135:195:135Ok, now I have to get into my machine and update this stuff.I used my normal SSH login to get a prompt. (user oetelx can use sudo because this user is in admin group)I checked if the new IP adresses actually are running a valid DNS server before assuming anything.oetelx@www:~$ dig @

; <<>> DiG 9.11.3-1ubuntu1.13-Ubuntu <<>> @
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 3218
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 1

; EDNS: version: 0, flags:; udp: 1280

#oetelx speed demon on gopro 8 timelapse

OETELX update2 : One minute on my desk : Orange PI Zero project update. #oetelx

Update 2 : #oetelx frequent content posting about stuff on the desk in one minute.

OETELX update1, Orange PI zero, USB, soldering, NFC device, Linux #oetelx

Find it by tag #oetelx : It has Linux, it is an Orange PI zero. I added Power over Ethernet. (POE) and it will read and program NFC cards that are used in Electric Cars (and the charge points) This is a proof of concept for a new Dutch Emobility provider called TandemDrive (located in Delft)

Just a one minute update. I plan to do more video's about my developments.

3D scan of model. Adummy new first aid articulated training device. #oetelx

The model is being scanned in a 3d point cloud and transformed into Nurbs. The 3d model is CNC milled a KUKA robot at Supportec BV. Find content with hashtag : #oetelx

versions of TiMO (tank beer monitoring system) #oetelx

The new version is the same size as a 9 Volt battery.
As you can clearly see this latest one matches the DuoTank logo.
(contact Duotank for purchase / implementation details)

Previous versions were reliable but fairly large. This one is still in operation.
This data is pushed to brewery ERP system to automatically optimize route planning of tanker vehicles. Currently installed in 23 location in the Netherlands with 100% uptime.

Find more content using hashtag : #oetelx

Beeld-classificatie, introductie TiMO tank kelderbier monitor #oetelx

De TiMO unit heeft een eigen camera en ziet dit, maar beeld-classificatie maakt menselijke ogen overbodig om te zien of de kelderbier-tank leeg is.

Is een woord net zo waardevol als het plaatje?
"een enkel woord is meer waardevol dan een plaatje", lees waarom.

Vaak is een enkel woord afgeleid uit een plaatje ook voldoende om een taak uit te voeren, dan hoef je het plaatje niet meer te bekijken.

Dit transformeren van een plaatje naar een woord of lijstje woorden noemen we beeld-classificatie.

Genoeg gepraat... waarom is dit belangrijk ?

De afgelopen 4 jaar is er heel veel door mij ontwikkeld om bovenstaande voor elkaar te krijgen, volledig automatisch met computer-hardware en nieuwe software, en ook nieuwe inzichten over hoe dit efficiënt kan.

Bij ABI loopt nu al 4 jaar de TiMO, 365 dagen per jaar alle dagen online.
Hier worden tientallen kelderbier-tanks op afstand gemonitord.
Dit ziet er voor de eindgebruiker-dashboard zo uit :

Als er ergens een tank leeg gaat verandert de kleur…

About me and you (a manifesto for freedom)

About me (and you)

I have been a technical person since I can remember.
Always taking stuff apart, trying to put it back together.
Always fixing stuff for people that can not do it themselves.
There are no limits to my curiosity.
I am always busy learning new things, it could be about design, engineering, music, psychology, art, writing or business. My personality is more like an artist than a perfectionist, I get things done and move on, a pragmatist as its called.
I have worked with and for the top 500 companies as a consultant, but have mixed feelings about the corporate world and the disregard of people and resources for the sake of short time financial profit.
This however does not mean I work for free or think money is evil. If you want to hire me you have bring your checkbook, no doubts there.
Freedom of expression and personal faith and expressing opinion, the freedom to live your life as you see fit, as a man a woman or otherwise, are the highest good.
I believe people as individua…

Github release of Controllino code "Het Concertgebouw" water dispensing #oetelx

Good day to you all.
I have just released this project I did in a day in 2016 under MIT license.
It was a project to help someone quickly get a water dispensing system up and running for "Het Concertgebouw" a famous building in the Netherlands.
The project was for a foundation "Join the Pipe" that tries to bring fresh drinking water to everyone in the world (Which is generally a positive thing).

The code was written in plain C (using Clion IDE for typing the code) on a linux system for an AVR ATMEGA 328P which is inside the Controllino Mini.

Hope you learn something from it.

Link to Github project :

It all worked and was delivered in a few days.

Some pictures tell more (maybe)

Find more content with hashtag : #oetelx

Nederland van het aardgas af, dat schiet lekker op (NOT!)

Om dingen even in perspectief te plaatsen moet je gewoon even wat berekeningen maken.
We gaan Nederland van het aardgas afhalen (de burgers) omdat?

In USA fakkelen ze 2123763,4944 m3 aardgas af per UUR
(bij winning van olie, gas is ongewenst daar, opslag niet handig, goedkoper om te fakkelen)

1.8 miljard cubic feet per dag...

Ons Nederlandse gasverbruik (huishoudens) is : 1500 m3 per jaar per huishouden

Even rekenen 2.1 miljoen m3 per uur, dat is

24 * 365 * 2.100.000,00 = 18.400.000.000,00 m3 aardgas affakkelen per jaar

(even de rekenmachine pakken)

18.400.000.000 / 1500 => aantal huishoudens Nederland

dat is voor 12.3 miljoen huishoudens (met gasverbruik van 1550 m3/jr)

Naast het opbranden lozen ze ook nog gewoon aardgas direct in de atmosfeer. (genaamd Venting)

Waarom moet ik ook alweer van het aardgas af?

Niet voor het milieu en de toekomst van onze kinderen, daarvoor helpt het helemaal…

ESP32 IDF master update troubles (and fix)

I am using ESP32 IDF for some private experiments. (more info later)

I really like it, not like some Arduino hobby IDE, that is a  half done, non-professional project.
I see a lot of people writing stuff like "do ESP32 in Arduino" this is completely backwards, you should avoid anything Arduino-related. You can not use Arduino in a real project, it can not be controlled, it is doing "magic" things and breaks everytime. You guessed it: I do not like it. ;-)

The ESP-IDF works really well uses cmake, is well documented, I use visual studio code insiders or clion van jetbrains to coordinate my coding and GIT to store my stuff.

I am really impressed with how well it works. Including flash-upload, debugging all works fine.

A few days ago I updated the IDF to the latest version and got errors:

$ git checkout master
$ git pull

remote: Enumerating objects: 1492, done.
remote: Counting objects: 100% (1492/1492), done.
remote: Compressing objects: 100% (213/213), done.
remote: Total…

Grinder and paint make me the welder I ain't.

Flux core.

It is not going anywhere soon!

Maidenhead locator to Degrees and back again

This code will convert a Maidenhead locator to Latitude/Longitude in degrees.
It seems that everyone tries to implement this, but I can not find any clean source code...

So here is my implementation, 2 ways, from lat,long -> maidenhead and reverse...
This is plain "C" code tested on linux, but I will include it on my STM32F4 dev board.

typedefstruct { double latitude; double longitude; int errorcode; } lat_lon_t; uint8_t to_upper(char c) { if (c >= 'a' && c <= 'z') { return c - 0x20; } return c; } // the equator and the 0 meridian are the reference // we call them +90 (instead of 0) and +180 (instead of 0) to prevent negative numbers // the world is divided into 18 * 18 fields (324 fields total) // these fields are sub-divided into squares and sub-squares and sub-sub-squares etc forever // but only 5 iterations make sense (size of a house) // and work on …

PCB looks just like the 3d rendering ;-) Update Secure Comm

Thanks to KiCAD and PCBWAY things look very nice.
The PCB arrived to my door in 6 days after sending the data to PCBWAY.COM
Time to heat up the soldering iron (vapour phase soldering is my way FYI, not the iron anymore)

Debugging in action, LED blinking, GDB running, Clion as my primary IDE for this project, integrates with CubeMX from ST. New V3 STLINK works great. The blink was active only 6 days after sending the PCB data to China. How about some fast development!

New project, END TO END encrypted texting and audio communications GLOBAL SAFE INTERCOM

Speaker modification for Old Timer Mercedes

Low power global connection with WSPR protocol it is so much fun

Conditions are good today.
I have my little transmitter with about 0.1 Watt of RF power (could be less).
I get my data across the globe : look here 40m band, from Netherlands to Antarctica, USA, Australia and more.
This is fun.
I am using a QRP labs kit :
My antenna is a piece of wire of about 10 meters hanging out of the window not a real antenna!

So much fun with so little RF power!
Best regards PA2LVD

Vapour Phase soldering, GALDEN LS230 experiment

Maxtor Shared Storage (how I recovered all the data)

Maxtor Shared Storage NAS 300 GB

Summary of long adventure: TL;DR.


- Audience : advanced users
- linux skill required : yes
- strong opinion : yes
- frustration : yes

It looks so nice in the picture : storing data on a NAS, not on the local system.
You can access it from anywhere in the network, all is fine.
Until.. The NAS breaks down and you forgot the backups..

I had this NAS for a long time (several years), somewhere safe in the house, in a dry and protected and cool place, nobody would be able to find it, a digital safe, connected to my local network.

It seems a smart idea, but it really was not.

Here is my summary of trouble to get my data back.
1) The NAS did not appear in my network anymore
2) Checked power supply, switches, cables
3) conclusion, NAS is bad
4) reboot, does not come online again
5) open it up, take out harddisk, how hard can it be? Right?

I connected the disk to my machine with one of those PATA/SATA-to-USB things (20 euro th…