While developing my website I frequently got warnings. The one below means WordPress tried to access the property slug of an object that doesn’t exist (is null) and, as mentioned elsewhere, this usually happens when a menu, a snippet or other piece of code references a category that no longer exist. Here are a few […]
While creating some code for the Arduino and C struct post, I ran into this issue “not enough values to unpack” and this has to do with Python’s struct format. This is the link to Python’s own exhaustive documentation on the topic. A Python struct format string is used to specify the layout when converting […]
While doing some tests with a 9-axis sensor I wnated to read all the values and send them all via an Arduino (or any other μ-controller) serial interface. You generate that data at point “A”, the sensor, and you want that data to arrive at point “B” with minimal delay, for example a computer software […]
I have a love-hate relationship with Adalm Pluto. I bought it from Mouser in 2020 when it was roughly 100 euros (now it is almost double that price !) and I never managed to do anything useful with it.
Lately I am doing a lot of development on Raspberry Pi systems and I use Visual Studio Code Remote Development. This is a neat feature because it allows me to connect from the same platform to multiple systems at once and work in parallel if I need. Visual Studio Code includes a full featured integrated […]
lsof command can show which processes are using which resources. This is extremely useful for troubleshooting. Basic syntax is: Without arguments, it lists all open files on the system (requires root privileges). Common Use Cases and Examples: Find which process is using a file: Find which process is using a port: The above command Lists […]
While developing my website I frequently got warnings. When WordPress tries to access the property slug of an object that doesn’t exist (is null), it throws the following (or similar) warning: This usually happens when a menu, a snippet or other piece of code references a category that no longer exist. This means somewhere in […]
There is a problem I forgot to take care before creating the custom image for my radio node project. Programming SA818 module via Raspberry Pi’s UART interface cannot be done unless the UART interface is released from any interaction in console mode. I was banging my head for hours because of sustained DMOERROR message for […]
Recently I had to make a bootable SD card for a Raspberry Pi Zero and I faced some issues. I thought to write some hints on how to properly clone and shrink a Pi image on an SD card. Here’s how you can create a compressed ISO (or disk image) from your Raspberry Pi SD […]
Most of my website posts that include code use syntaxhighlighter to nicely format code. Unfortunately, you have to manually tag the piece of text as code. I thought it would be nice to have one or more buttons in the classical editor toolbar that will automatically surround the code with needed tags to be displayed […]
Here are some handy commands that can be used to check the hardware version on a Linux-based machine.
I want to get back to FPGA design because I have some projects in mind and I did some in the past that were quite fun and very interesting. I am a bit rusty, though, and I am afraid I have to review all my past, and very diluted, experience with FPGAs. This has a […]
Recently I hit a blocker when using journalctl -b -1 did not work. Using the flags ended up in error
The autumn 2025 edition of Tuzla Field Day, Constanța, Romania, took place between 16 and 22 september. A lovely event, an occasion to meet old friends and make new ones.
I recently ran into an issue with my Raspberry-based radio node. I tried to connect to some othet WiFi access points and I realized that I had no idea how to set connection priorities if I have multiple candidates for connection. I was used with wpa-supplicant way of doing things which was just to add […]
CM108 has a set of four GPIOs that can be used via hidraw. These can be read from or write to.
Today I did some thermal measurements with my Flir C2.
My new radio node that I designed last month is back from production at jlcpcb. Designed in Romania and built in China 😁. This is my first attempt using jlcpcb for the entire manufacturing chain, from PCB creation to part selection and assembly.
There is a problem (or I am doing something terribly wrong !) with the coordinate system in KiCad.
I am already one week into the design of the PCB for my new radio node and today I discovered some schematic errors that I had to fix. Running the DRC (Design Rule Check[er]) KiCad threw some schematic parity errors which “occurs when there’s a mismatch between the schematic diagram and the physical PCB (printed […]
Today I finalzied the designed for my new Raspberry Pi Zero-based radio node. Designed around SA818 and CM108B sound codec, will replace my old dead-bug style radio node that I used for so many years.
More work today. Some wires got loose and I did some experiments with .asoundrc and ALSA settings. I added a 39 Ω ballast resistor on SDIN and SDOUT lines and put a ferrite core on both wires. The radio node works as expected, absolutely no issues with one exception, a periodic pop that is audible […]
Update July 11, 2025 Some thoughts and tasks today. The project is the same I2S interface.
I have some Si5351 chips that I never used for any projects. I purchased them from Mouser, I believe for an APRS project, long-standing and overdue. That APRS project I started some time ago but I never completed and maybe I should strongly consider to complete. But this is another topic.
These days we are at Tuzla, in the sunny Dobrogea, on the Black Sea coast, for the sixth edition of Tuzla Ham Radio Field Day. From May 21st to May 25th. Amazing for this event is our desire to meet and socialize. In a world and time when people spend more time with bots and […]
While testing my I2S project I ran into some boot issues on the Raspberry Pi 4 host. For what seemed to be some unknown reasons the boot process was completely chaotic, sometimes running well, sometimes hanging. I banged my head for some time looking for a solution until it came to my mind to change […]
RDA1846, the transceiver inside Baofeng UV-5R, Yaesu FT-4XR, SA818 and other radios is no longer manufactured. There are equivalent chips that can be used.
Update September, 2024. Activities and notes while developing the I2S interface for my radio node.
Today I managed to connect the Digilent Pmod I2S2 to a Raspberry Pi 4 and have all frequencies generated. This is part of an older project that I left abandoned for a while: a radio node built on Raspberry Pi and using Svxlink. As known, Raspberry boards do not have a proper audio interface and […]
I made this for a friend. Is a remote controller for Yaesu DR-1X repetear that is installed on Summit Heniu (145.725 Tx -6khz Rx). This is a mixed digital (C4FM) and analogue repeater that is covering almost all northern half of Transyvania and can also be accessed via Echolink YO5D-R, node 54452. This version is […]
