Radio Repeaters In The Sky

April 30, 2025 by 10 Comments

One of the first things that an amateur radio operator is likely to do once receiving their license is grab a dual-band handheld and try to make contacts with a local repeater. After the initial contacts, though, many hams move on to more technically challenging aspects of the hobby. One of those being activating space-based repeaters instead of their terrestrial counterparts. [saveitforparts] takes a look at some more esoteric uses of these radio systems in his latest video.

There are plenty of satellite repeaters flying around the world that are actually legal for hams to use, with most being in low-Earth orbit and making quick passes at predictable times. But there are others, generally operated by the world’s militaries, that are in higher geostationary orbits which allows them to serve a specific area continually. With a specialized three-dimensional Yagi-Uda antenna on loan, [saveitforparts] listens in on some of these signals. Some of it is presumably encrypted military activity, but there’s also some pirate radio and state propaganda stations.

There are a few other types of radio repeaters operating out in space as well, and not all of them are in geostationary orbit. Turning the antenna to the north, [saveitforparts] finds a few Russian satellites in an orbit specifically designed to provide polar regions with a similar radio service. These sometimes will overlap with terrestrial radio like TV or air traffic control and happily repeat them at brief intervals.

[saveitforparts] has plenty of videos looking at other satellite communications, including grabbing images from Russian weather satellites, using leftover junk to grab weather data from geostationary orbit, and accessing the Internet via satellite with 80s-era technology.

Continue reading “Radio Repeaters In The Sky” →

A Gentle Introduction To COBOL

April 30, 2025 by 70 Comments

As the Common Business Oriented Language, COBOL has a long and storied history. To this day it’s quite literally the financial bedrock for banks, businesses and financial institutions, running largely unnoticed by the world on mainframes and similar high-reliability computer systems. That said, as a domain-specific language targeting boring business things it doesn’t quite get the attention or hype as general purpose programming or scripting languages. Its main characteristic in the public eye appears be that it’s ‘boring’.

Despite this, COBOL is a very effective language for writing data transactions, report generating and related tasks. Due to its narrow focus on business applications, it gets one started with very little fuss, is highly self-documenting, while providing native support for decimal calculations, and a range of I/O access and database types, even with mere files. Since version 2002 COBOL underwent a number of modernizations, such as free-form code, object-oriented programming and more.

Without further ado, let’s fetch an open-source COBOL toolchain and run it through its paces with a light COBOL tutorial.

Continue reading “A Gentle Introduction To COBOL” →

Terminal DAW Does It In Style

April 30, 2025 by 30 Comments

As any Linux chat room or forum will tell you, the most powerful tool to any Linux user is a terminal emulator. Just about every program under the sun has a command line alternative, be it CAD, note taking, or web browsing. Likewise, the digital audio workstation (DAW) is the single most important tool to anyone making music. Therefore, [unspeaker] decided the two should, at last, be combined with a terminal based DAW called Tek.

Tek functions similarly to other DAWs, albeit with keyboard only input. For anyone used to working in Vim or Emacs (we ask you keep the inevitable text editor comment war civil), Tek will be very intuitive. Currently, the feature set is fairly spartan, but plans exist to add keybinds for save/load, help, and more. The program features several modes including a multi-track sequencer/sampler called the “arranger.” Each track in the arranger is color coded with a gradient of colors generated randomly at start for a fresh look every time.

Modern audio workflows often span across numerous programs, and Tek was built with this in mind. It can take MIDI input and output from the JACK Audio Connection Kit, and plans also exist to create a plugin server so Tek could be used with other DAWs like Ardor or Zrythm. Moreover, being a terminal program opens possibilities for complicated shell scripting and other such Linux-fu.

Maybe a terminal DAW is not your thing, so make sure to check out this physical one instead!

Building An NRF52840 And Battery-Powered Zigbee Gate Sensor

April 30, 2025 by 23 Comments

Recently [Glen Akins] reported on Bluesky that the Zigbee-based sensor he had made for his garden’s rear gate was still going strong after a Summer and Winter on the original 2450 lithium coin cell. The construction plans and design for the unit are detailed in a blog post. At the core is the MS88SF2 SoM by Minew, which features a Nordic Semiconductor nRF52840 SoC that provides the Zigbee RF feature as well as the usual MCU shenanigans.

Previously [Glen] had created a similar system that featured buttons to turn the garden lights on or off, as nobody likes stumbling blindly through a dark garden after returning home. Rather than having to fumble around for a button, the system should detect when said rear gate is opened. This would send a notification to [Glen]’s phone as well as activate the garden lights if it’s dark outside.

Although using a reed relay switch seemed like an obvious solution to replace the buttons, holding it closed turned out to require too much power. After looking at a few commercial examples, he settled for a Hall effect sensor solution with the Ti DRV5032FB in a TO-92 package.

Whereas the average person would just have put in a PIR sensor-based solution, this Zigbee solution does come with a lot more smart home creds, and does not require fumbling around with a smartphone or yelling at a voice assistant to turn the garden lights on.

Back To Reality With The Time Brick

April 29, 2025 by 8 Comments

There are a lot of distractions in daily life, especially with all the different forms of technology and their accompanying algorithms vying for our attention in the modern world. [mar1ash] makes the same observation about our shared experiences fighting to stay sane with all these push notifications and alerts, and wanted something a little simpler that can just tell time and perhaps a few other things. Enter the time brick.

The time brick is a simple way of keeping track of the most basic of things in the real world: time and weather. The device has no buttons and only a small OLED display. Based on an ESP-01 module and housed in a LEGO-like enclosure, the USB-powered clock sits quietly by a bed or computer with no need for any user interaction at all. It gets its information over a Wi-Fi connection configured in the code running on the device, and cycles through not only time, date, and weather but also a series of pre-programmed quotes of a surreal nature, since part of [mar1ash]’s goals for this project was to do something just a little bit outside the norm.

There are a few other quirks in this tiny device as well, including animations for the weather display, a “night mode” that’s automatically activated to account for low-light conditions, and the ability to easily handle WiFi drops and other errors without crashing. All of the project’s code is also available on its GitHub page. As far as design goes, it’s an excellent demonstration that successful projects have to avoid feature creep, and that doing one thing well is often a better design philosophy than adding needless complications.

Comparing ‘AI’ For Basic Plant Care With Human Brown Thumbs

April 29, 2025 by 18 Comments

The future of healthy indoor plants, courtesy of AI. (Credit: [Liam])
The future of healthy indoor plants, courtesy of AI. (Credit: [Liam])
Like so many of us, [Liam] has a big problem. Whether it’s the curse of Brown Thumbs or something else, those darn houseplants just keep dying despite guides always telling you how incredibly easy it is to keep them from wilting with a modicum of care each day, even without opting for succulents or cactuses. In a fit of despair [Liam] decided to pin his hopes on what we have come to accept as the Savior of Humankind, namely ‘AI’, which can stand for a lot of things, but it’s definitely really smart and can even generate pretty pictures, which is something that the average human can not. Hence it’s time to let an LLM do all the smart plant caring stuff with ‘PlantMom’.

Since LLMs so far don’t come with physical appendages by default, some hardware had to be plugged together to measure parameters like light, temperature and soil moisture. Add to this a grow light and a water pump and all that remained was to tell the LMM using an extensive prompt, containing Python code, what it should do (keep the the plant alive), and what Python methods are available. All that was left now was to let the Google’s Gemma 3 handle it.

To say that this resulted in a dramatic failure along with what reads like an emotional breakdown on the part of the LLM would be an understatement. The LLM insisted on turning the grow light on when it should be off and had the most erratic watering responses imaginable based on absolutely incorrect interpretations of the ADC data, flipping dry and wet. After this episode the poor chili plant’s soil was absolutely saturated and is still trying to dry out, while the ongoing LLM experiment, with an empty water tank, has the grow light blasting more often than a weed farm.

So far it seems like that the humble state machine’s job is still safe from being taken over by ‘AI’, and not even brown thumb folk can kill plants this efficiently.

Read Motor Speed Better By Making The RP2040 PIO Do It

April 29, 2025 by 8 Comments

A quadrature encoder provides a way to let hardware read movement (and direction) of a shaft, and they can be simple, effective, and inexpensive devices. But [Paulo Marques] observed that when it comes to reading motor speeds with them, what works best at high speeds doesn’t work at low speeds, and vice versa. His solution? PicoEncoder is a library providing a lightweight and robust method of using the Programmable I/O (PIO) hardware on the RP2040 to get better results, even (or especially) from cheap encoders, and do it efficiently. Continue reading “Read Motor Speed Better By Making The RP2040 PIO Do It” →