Graphene isn’t easy to produce at scale. But making small batches of graphene is doable in a few ways. [Robert Murray-Smith] decided to try producing “flash graphene.” This requires a big capacitor bank that is moderately expensive, so he decided to explain a different technique he read about using an ordinary laser cutter. Check it out in the video below.
We were a little disappointed that he didn’t actually make any graphene this time. He has, however, used other methods in other videos to create some type of graphene. In fact, he has many similar videos going back quite a ways as well as applications with concrete, capacitors, and more. We understand that this method doesn’t produce monolayer graphene, but actually creates a graphene “foam” with interesting properties. [Robert] talks about recent papers that show you can grow graphene on things other than Kapton tape using this method.
Continue reading “Easy Graphene Production With A Laser Engraver” →
In recent years small drones have gone from being toys and photography tools to a deadly threat on the battlefield. Kamikaze drones have become especially prominent in the news due to their use in the war in Ukraine by both sides. While we haven’t seen coordinated swarms being actively employed on the modern battlefield, it’s likely only a matter of time, making drone swarm defense an active field of development in the industry.
The US Air Force Research Laboratory recently conducted tests and a demonstration of an anti-drone weapon that uses pulses of high-power microwave energy to fry the electronics of a swarm of drones. Named the Tactical High-power Operational Responder, or THOR (presumably they picked the acronym first), it’s housed in a 20ft shipping container with large microwave antenna on top. The form factor is important because a weapon is only useful if it can reach the battlefield, and this can fit in the back of a C130.
THOR likely functions similarly to a shotgun, with a relatively large effective “beam.” This would have added advantages like frying multiple drones with one pulse and not needing pinpoint tracking and aiming tech required for projectile and laser-based weapons. Depending on its range and directivity, THOR might come with the downside of collateral damage to electronics close to its line of fire.
Drone swarms are of course the other side of this arms race, but fortunately they also have non-destructive uses like lights shows and perhaps even 3D printing.
Integrating non-smart devices into your home automation system can be a cumbersome process, involving the wiring of multiple modules. However, [Pricelesstoolkit] has created the ESPClicker — a compact, ESP8266-based module that can remotely “press buttons” and simplify this process.
The ESPClicker’s core feature is its three relays that can be soldered to the button terminals of any existing “dumb” device, as [Pricelesstoolkit] demonstrated with his coffee machine in the video after the break. One of the relays can also be configured in the normally closed configuration. A compact twelve pin connector provides a removable wiring interface for the buttons, additional relays, power and even a contactless power detector that can be wrapped around an AC wire.
[PricelessToolkit] has done several Home Assistant related projects, and we recently featured his little Home Assistant controlled guardian bot. We’ve also seen other project that make use of ESPHome, like a iPod style scroll wheel and a LEGO train set.
Continue reading “An Elegant Solution For Smart Home Device Integration” →
When it comes to our analog designs, op-amps tend to be just another jellybean part. We tend to spec whatever does the job, and don’t give much of a thought as to the internals. And while it doesn’t make much sense to roll your own op-amp out of discrete components, that doesn’t mean there isn’t plenty to be learned from doing just that.
While we’re more accustomed to seeing [Mitsuru Yamada]’s digital projects, he’s no stranger to the analog world. In fact, this project is a follow-on to his previous bipolar transistor op-amp, which we featured back in 2021. This design features MOSFETs rather than BJTs, but retains the same basic five-transistor topology as the previous work, with a differential pair input stage, a gain stage, and a buffer stage. Even the construction of the module is similar, using his trademark perfboard and ultra-tidy wiring.
Also new is a flexible evaluation unit for these discrete op-amp modules. This very sturdy-looking circuit provides an easy way to configure the op-amp for testing in inverting, non-inverting, and transimpedance mode, selecting from a range of feedback resistors, and even provides a photodiode input. The video below shows the eval unit in action with the CMOS module, as well as highlights the excellent construction [Mitsuru Yamada] is known for.
Looking for some digital goodness? Check out the PERSEUS-8, a 6502 machine we wish had been a real product back in the day.
Continue reading “Op-Amp Challenge: MOSFETs Make This Discrete Op Amp Tick” →
We’ve seen the 1993 id Software classic DOOM running on so many pieces of unexpected hardware, as “Will it run DOOM?” has become something of a test for any new device. But will it run in the circuitry of a 1970s or 1980s TV set? Not quite, but as [lukneu] has demonstrated, it is possible to render the game using the set’s inbuilt Teletext decoder.
Teletext is a technology past its zenith and which is no longer broadcast in many countries, but for those unfamiliar it’s an information service broadcast in the unseen lines hidden in the frame blanking period of an analogue TV transmission. Its serial data packets can contain both pages of text and rudimentary block graphics, and we’re surprised to learn, can include continuous streams to a single page. It’s this feature that he’s used, piping the game’s graphics as a teletext stream which is decoded by the CRT TV and displayed as a playable if blocky game.
Delving further, we find that DOOM is running on a Linux machine on which the teletext stream is created, and the stream is then piped to a Raspberry Pi which does the encoding on to its composite video output. More powerful versions of the Pi can run both processes on the same machine. The result can be seen in the video below, and we can definitely say it would have been mind-blowing, back when DOOM was king. There are plans for further refinement, of which we’d say that color would be the most welcome.
Continue reading “It’s DOOM, But In Teletext” →
We read this news with mixed glee and horror: a company called Telly is giving TVs away, for the low price of having to live with an always-on advertisement bar and some pretty stringent terms and conditions. Break the terms, and they’ll repossess your TV. If you don’t give them the TV, they have your credit card on record and they think the set is worth $1,000.
The hacker in me sees free hardware, so I checked out the terms and conditions, and it doesn’t look good. They’ve explicitly ruled out opening up or physically modifying the device, and it has to continually have WiFi – for which you pay, naturally. It sounds like it could easily tell if you try to tamper with it. My next thought was, perhaps too cynically, to get one, put it in the closet, and wait for the company to go bankrupt. Because you know that business model isn’t going to last.
But it’s clear that they’ve seen through me. The most bizarre clause is that you have to “Use the Product as the primary television in Your household”. Now, we’re not lawyers, but it seems like an amazing stretch that they can tell you how intensively you are to use the product. Can you imagine a license with a keyboard that demanded that you only use it to write sci-fi novels, or that you have to use it more than any other keyboard?
Nope. Too many hoops to jump through for a silly free TV. You can keep your dystopian future.
You can babysit your 3D printer 100% of the time, or you can cross your fingers and hope it all works. Some monitor their printers using webcams, but [Simit] has a more stylish method of keeping tabs on six 3D printers.
The idea is to use a 3D printed hex LED display found online. Adding an ESP32 and Home Assistant allows remote control of the display. The printers use Klipper and can report their status using an API called Moonraker. Each hexagon shows the status of one printer. You can tell if the printer is online, paused, printing, or in other states based on the color and amount of LEDs lit. For example, a hex turns totally green when printing is complete.
Once you have a web API and some network-controlled LEDs, it is relatively straightforward to link it together with Home Automation. Of course, you could do it other ways, too, but if you already have Home Automation running for other reasons, why not?
We have seen other ways to do this, of course. If you need an easy monitor, the eyes have it. If you don’t use Klipper, OctoPrint can pull a similar stunt.