Exploring The Early Days Of QRP Radio

May 10, 2023 by 23 Comments

Morse code might seem obsolete but for situations with extremely limited bandwidth it’s often still the best communications option available. The code requires a fair amount of training to use effectively, though, and even proficient radio operators tend to send only around 20 words per minute. As a result of the reduced throughput, a type of language evolved around Morse code which, like any language, has evolved and changed over time. QRP initially meant something akin to “you are overloading my receiver, please reduce transmitter power” but now means “operating radios at extremely low power levels”. [MIKROWAVE1] explores some of the earlier options for QRP radios in this video.

There’s been some debate in the amateur radio community over the years over what power level constitutes a QRP operation, but it’s almost certainly somewhere below 100 watts, and while the radios in this video have varying power levels, they tend to be far below this upper threshold, with some operating on 1 watt or less. There are a few commercial offerings demonstrated here, produced from the 70s to the mid-80s, but a few are made from kits as well. Kits tended to be both accessible and easily repairable, with Heathkit being the more recognizable option among this category. To operate Morse code (or “continuous wave” as hams would call it) only requires a single transistor which is why kits were so popular, but there are a few other examples in this video with quite a few more transistors than that. In fact, there are all kinds of radios featured here with plenty of features we might even consider modern by today’s standards; at least when Morse code is concerned.

QRP radios in general are attractive because they tend to be smaller, simpler, and more affordable. Making QRP contacts over great distances also increases one’s ham radio street cred, especially when using Morse, although this benefit is more intangible. There’s a large trend going on in the radio world right now surrounding operating from parks and mountain peaks, which means QRP is often the only way to get that done especially when operating on battery power. Modern QRP radios often support digital and voice modes as well and can have surprisingly high prices, but taking some cues from this video about radios built in decades past could get you on the radio for a minimum or parts and cost, provided you can put in the time.

Continue reading “Exploring The Early Days Of QRP Radio” →

3D Print For Extreme Temperatures (But Only If You’re NASA)

April 25, 2023 by 23 Comments

At the level pursued by many Hackaday readers, the advent of affordable 3D printing has revolutionised prototyping, as long as the resolution of a desktop printer is adequate and the part can be made in a thermoplastic or resin, it can be in your hands without too long a wait. The same has happened at a much higher level, but for those with extremely deep pockets it extends into exotic high-performance materials which owners of a desktop FDM machine can only dream of.

NASA for example are reporting their new 3D printable nickel-cobalt-chromium alloy that can produce extra-durable laser-sintered metal parts that van withstand up to 2000 Fahrenheit, or 1033 Celcius for non-Americans. This has obvious applications for an organisation producing spacecraft, so naturally they are excited about it.

The alloy receives some of its properties because of its oxide-dispersion-strengthened composition, in which grains of metal oxide are dispersed among its structure. We’re not metallurgists here at Hackaday, but we understand that the inconsistencies in the layers of metal atoms caused by the oxides in the crystal structure of the alloy leads to a higher energy required for the structure to shear.

While these particular materials might never be affordable for us mere mortals to play with, NASA’s did previously look into how it could greatly reduce the cost of high-temperature 3D printing by modifying an existing open source machine.

OSI Superboard II Replicated

April 24, 2023 by 6 Comments

While our modern computer can easily emulate a lot of different old machines, there is something about having replica hardware that is even better. Not as nice as having the real thing, in some ways, although you don’t have to worry about wear and tear on a replica, either. [Jeff Tranter] has built a kit replica of an Ohio Scientific Superboard II, and it looks great, as you can see in the video below.

This was an inexpensive all-in-one 6502 computer with a keyboard and provision for TV or monitor output. If you had a 5V power supply, a cassette deck, and a TV you were in business for less money than most of the comparable alternatives. In fact, [Jeff] has the canceled check where his parents paid $486 Canadian for one in 1981. That was his introduction to computing, and we’d say that was a reasonable investment on the part of his parents.

Continue reading “OSI Superboard II Replicated” →

MRI Resolution Progresses From Millimeters To Microns

April 20, 2023 by 15 Comments

Neuroscientists have been mapping and recreating the nervous systems and brains of various animals since the microscope was invented, and have even been able to map out entire brain structures thanks to other imaging techniques with perhaps the most famous example being the 302-neuron brain of a roundworm. Studies like these advanced neuroscience considerably but even better imaging technology is needed to study more advanced neural structures like those found in a mouse or human, and this advanced MRI machine may be just the thing to help gain better understandings of these structures.

A research team led by Duke University developed this new MRI technology using an incredibly powerful 9.4 Tesla magnet and specialized gradient coils, leading to an image resolution an impressive six orders of magnitude higher than a typical MRI. The voxels in the image measure at only 5 microns compared to the millimeter-level resolution available on modern MRI machines, which can reveal microscopic details within brain tissues that were previously unattainable. This breakthrough in MRI resolution has the potential to significantly advance understanding of the neural networks found in humans by first studying neural structures in mice at this unprecedented detail.

The researchers are hopeful that this higher-powered MRI microscope will lead to new insights and translate directly into advancements healthcare, and presuming that it can be replicated, used on humans safely, and becomes affordable, we would expect it to find its way into medical centers as soon as possible. Not only that, but research into neuroscience has plenty of applications outside of healthcare too, like the aforementioned 302-neuron brain of the Caenorhabditis elegans roundworm which has been put to work in various robotics platforms to great effect.

Continue reading “MRI Resolution Progresses From Millimeters To Microns” →

Peering Down Into Talking Ant Hill

April 19, 2023 by 14 Comments

Watching an anthill brings an air of fascination. Thousands of ants are moving about and communicating with other ants as they work towards a goal as a collective whole. For us humans, we project a complex inner world for each of these tiny creatures to drive the narrative. But what if we could peer down into a miniature world and the ants spoke English? (PDF whitepaper)

Researchers at the University of Stanford and Google Research have released a paper about simulating human behavior using multiple Large Language Models (LMM). The simulation has a few dozen agents that can move across the small town, do errands, and communicate with each other. Each agent has a short description to help provide context to the LLM. In addition, they have memories of objects, other agents, and observations that they can retrieve, which allows them to create a plan for their day. The memory is a time-stamped text stream that the agent reflects on, deciding what is important. Additionally, the LLM can replan and figure out what it wants to do.

The question is, does the simulation seem life-like? One fascinating example is the paper’s authors created one agent (Isabella) intending to have a Valentine’s Day party. No other information is included. But several agents arrive at the character’s house later in the day to party. Isabella invited friends, and those agents asked some people.

A demo using recorded data from an earlier demo is web-accessible. However, it doesn’t showcase the powers that a user can exert on the world when running live. Thoughts and suggestions can be issued to an agent to steer their actions. However, you can pause the simulation to view the conversations between agents. Overall, it is incredible how life-like the simulation can be. The language of the conversation is quite formal, and running the simulation burns significant amounts of computing power. Perhaps there can be a subconscious where certain behaviors or observations can be coded in the agent instead of querying the LLM for every little thing (which sort of sounds like what people do).

There’s been an exciting trend of combining LLMs with a form of backing store, like combining Wolfram Alpha with chatGPT. Thanks [Abe] for sending this one in!

Noninvasive Sensors For Brain–Machine Interfaces Based On Micropatterned Epitaxial Graphene

April 15, 2023 by 4 Comments

As fun as brain-computer interfaces (BCI) are, for the best results they tend to come with the major asterisk of requiring the cutting and lifting of a section of the skull in order to implant a Utah array or similar electrode system. A non-invasive alternative consists out of electrodes which are placed on the skin, yet at a reduced resolution. These electrodes are the subject of a recent experiment by [Shaikh Nayeem Faisal] and colleagues in ACS Applied NanoMaterials employing graphene-coated electrodes in an attempt to optimize their performance.

Impedance values of eight-channel FEG and eight-channel HPEG sensor systems placed on the occipital area of the head. (Faisal et al., 2023)
Impedance values of eight-channel FEG and eight-channel HPEG sensor systems placed on the occipital area of the head. (Faisal et al., 2023)

Although external electrodes can be acceptable for basic tasks, such as registering a response to a specific (visual) impulse or for EEG recordings, they can be impractical in general use. Much of this is due to the disadvantages of the ‘wet’ and ‘dry’ varieties, which as the name suggests involve an electrically conductive gel with the former.

This gel ensures solid contact and a resistance of no more than 5 – 30 kΩ at 50 Hz, whereas dry sensors perform rather poorly at >200 kΩ at 50 Hz with worse signal-to-noise characteristics, even before adding in issues such as using the sensor on a hairy scalp, as tends to be the case for most human subjects.

In this study, they created electrode arrays in a number of configurations, each of which used graphene as the interface material. The goal was to get a signal even through human hair — such as on the back of the head near the visual cortex — that would be on-par with wet electrodes. The researchers got very promising results with hex-patterned epitaxial graphene (HEPG) sensors, and even in this early prototype stage, the technique could offer an alternative where wet electrodes are not an option.

While the subject is complex, brain-computer interfaces don’t have to be the sole domain of research laboratories. We recently covered an open hardware Raspberry Pi add-on that can let you experiment with detecting and filtering biosignals from the comfort of your own home.

The Challenges Of Producing Graphene In Quantity

April 12, 2023 by 26 Comments

We’ve all heard the incredible claims made about graphene and its many promising applications, but so far the wonder-material has been held back by the difficulty of producing it in large quantities. Although small-scale production was demonstrated many years ago using basic Scotch tape, producing grams or even kilograms of it in a scalable industrial process seemed like a pipedream — until recently. As [Tech Ingredients] demonstrates in a new video, the technique of flash Joule heating of carbon may enable industrial graphene production.

The production of this flash graphene (FG) was first demonstrated by Duy X. Luong and colleagues in a 2020 paper in Nature, which describes a fairly straightforward process. In the [Tech Ingredients] demonstration it becomes obvious how easy graphene manufacturing is using this method, requiring nothing more than carbon black as ingredient, along with a capacitor bank, vacuum chamber and a number of reasonably affordable items.

Perhaps best of all is that no refinement or other complicated processes are required to separate the produced graphene from the left-over carbon black and other non-graphene products. Using multiple of these carbon black-filled tubes in parallel, producing graphene could conceivably be scaled up to industrial levels. This would make producing a few kilograms of graphene significantly easier than coating hard drive platters with the substance.

Continue reading “The Challenges Of Producing Graphene In Quantity” →