A Gentle Introduction To COBOL

April 30, 2025 by Maya Posch 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.

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Terminal DAW Does It In Style

April 30, 2025 by Fenix Guthrie 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 Maya Posch 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 Bryan Cockfield 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 Maya Posch 18 Comments

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 Donald Papp 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” →

Crossing Commodore Signal Cables On Purpose

April 29, 2025 by Bryan Cockfield 19 Comments

On a Commodore 64, the computer is normally connected to a monitor with one composite video cable and to an audio device with a second, identical (although uniquely colored) cable. The signals passed through these cables are analog, each generated by a dedicated chip on the computer. Many C64 users may have accidentally swapped these cables when first setting up their machines, but [Matthias] wondered if this could be done purposefully — generating video with the audio hardware and vice versa.

Getting an audio signal from the video hardware on the Commodore is simple enough. The chips here operate at well over the needed frequency for even the best audio equipment, so it’s a relatively straightforward matter of generating an appropriate output wave. The audio hardware, on the other hand, is much less performative by comparison. The only component here capable of generating a fast enough signal to be understood by display hardware of the time is actually the volume register, although due to a filter on the chip the output is always going to be a bit blurred. But this setup is good enough to generate large text and some other features as well.

There are a few other constraints here as well, namely that loading the demos that [Matthias] has written takes so long that the audio can’t be paused while this happens and has to be bit-banged the entire time. It’s an in-depth project that shows mastery of the retro hardware, and for some other C64 demos take a look at this one which is written in just 256 bytes.

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