Kritik sah

One of the good things about simulating circuits is that you can easily change component values trivially. In the real world, you might use a potentiometer or a pot to provide an adjustable value. However, as [Ralph] discovered, there’s no pot component in LTSpice. At first, he cobbled up a fake pot with two resistors, one representing the top terminal to the wiper, and the other one representing the wiper to the bottom terminal. Check it out in the video below. At first, [Ralph] just set values for the two halves manually, making sure not to set either resistor to zero so as not to merge the nets. However, as you might guess, you can make the values parameters and then step them.  By using .step you can alter one of the resistor values. Then you can use a formula to compute the other resistor since the sum of the two resistors has to add up to the pot’s total value. That is, a 10K pot will have the two resistors always add up to 10K. Of course, you could do this without the ....

Normally, if you want to blast out samples to a DAC in a hurry, you’d rely on an FPGA, what with their penchant for doing things very quicky and in parallel. However, [Anabit] figured out a way to do the same thing with a microcontroller , thanks to the magic of the Raspberry Pi Pico 2. The design in question is referred to as the PiWave 150 MS/s Bipolar DAC, and as the name suggests, it’s capable of delivering a full 150 million samples per second with 10, 12, or 14 bits of resolution. Achieving that with a microcontroller would normally be pretty difficult. In regular linear operation, it’s hard to clock bits out to GPIO pins at that sort of speed. However, the Raspberry Pi Pico 2 serves as a special case in this regard, thanks to its Programmable I/O (PIO) subsystem. It’s a state machine, able to be programmed to handle certain tasks entirely independently from the microcontroller’s main core itself, and can do simple parallel tasks very quickly. Since it can grab data from RAM an...

Well there’s your problem. (Credit: Mark Funeaux, YouTube) Akin to the razor-and-blades model, capsule-based coffee machines are an endless grind of overpriced pods and cheaply made machines that you’re supposed to throw out and buy a new one of, just so that you don’t waste all the proprietary pods you still have at home. What this also means is a seemingly endless supply of free broken capsule coffee makers that might be repairable. This is roughly how [Mark Furneaux] got into the habit of obtaining various Nespresso VertuoLine machine for attempted repairs . The VirtuoLine machines feature the capsule with a bar code printed on the bottom of the lip, requiring the capsule to be spun around so that it can be read by the optical reader. Upon successful reading, the code is passed to the MCU after which the brewing process is either commenced or cruelly halted if the code fails. Two of the Vertuo Next machines that [Mark] got had such capsule reading errors, leading to a full tear...

This week Jonathan chats with Nicholas Adams about OpenRiak ! Why is there a Riak and an OpenRiak, which side of the CAP theorem does OpenRiak land on, and why is it so blazingly fast for some operations? Listen to find out! https://www.linkedin.com/groups/14551410/ https://github.com/openriak/ https://join.slack.com/t/postriak/shared_invite/zt-3i0e8alkg-hUKkWVcJQhWt5IzmQQ9I0w https://files.tiot.jp/riak/ https://www.tiot.jp/riak-docs/ https://www.meetup.com/tokyo-openriak-meetup-group/ Did you know you can watch the live recording of the show right on our YouTube Channel ? Have someone you’d like us to interview? Let us know, or have the guest contact us! Take a look at the schedule here . Direct Download in DRM-free MP3. If you’d rather read along, here’s the transcript for this week’s episode . Places to follow the FLOSS Weekly Podcast: Spotify RSS Theme music: “Newer Wave” Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4....

DDR3 seemed plenty fast when it first showed up 19 years ago. Who could say no to 6400 Mb/s transfer speeds? Of course compared to the modern DDR5 that’s glacially slow, but given that RAM is worth its weight in gold these days– with even DDR4 spiking in price– some people, like [Gheeotine], are asking “ can you game on DDR3 “? The answer is a shocking yes. [Gheeotine] builds two budget-friendly PCs for this video, using some of the newest DD3-supporting motherboards available. That’s not exactly new: we’re talking 12 to 15 years old, but hey, not old enough to drive. We certainly didn’t expect to hear about an x79 motherboard hosting an Ivy Bridge processor in 2026, but needs must when the devil dances. The only concession to modernity is the graphics cards: the x79 mobo got an RX6600XT 8GB, and the other build, using a z97 motherboard got an NVIDIA RTX 4060. The z97 motherboard allowed a slightly newer processor, as well, an i7 4790, with the new and exciting Haswell architecture y...

When you’re driving a car with a stickshift, it’s pretty easy to keep track of which gear you’re in. That can be a little bit more difficult on something like a motorcycle with a sequential shifter. [decogabry] built a neat gearshift indicator to solve this issue. An ESP32 devboard is used as the brain of the build. It’s paired with an ELM327 dongle over Bluetooth, which is able to hook into the bike’s ODB diagnostic port to pick up data like engine RPM, wheel speed, and coolant temperature. The first two factors are combined in order to calculate the current gear, since the ratio between engine RPM and wheel speed is determined directly by the gear selection. The ESP32 then commands a Philips ZM1020 Nixie tube to display the gear, driving it via a small nest of MPSA42 transistors. A separate self-contained power supply module is used to take the bike’s 12 volt supply up to the 170 volts needed to run the tube. There is also a small four-digit display used to show status information,...

If you were asked to pick the most annoying of the various Microsoft Windows interfaces that have appeared over the years, there’s a reasonable chance that Windows 8’s Metro start screen and interface design language would make it your choice. In 2012 the software company abandoned their tried-and-tested desktop whose roots extended back to Windows 95 in favor of the colorful blocks it had created for its line of music players and mobile phones. Consumers weren’t impressed and it was quickly shelved in subsequent versions, but should you wish to revisit Metro you can now get the experience on Linux . [er-bharat] has created Win8DE, a shell for Wayland window managers that brings the Metro interface — or something very like it — to the open source operating system. We have to admire his chutzpah in bringing the most Microsoft of things to Linux, and for doing so with such a universally despised interface. But once the jibes about Windows 8 have stopped, we can oddly see a point here....

Space telescopes are all the rage, and rightfully so. The images they take are spectacular, and they’ve greatly increased what we know about the universe. Surely, any picture taken of, say, the Andromeda galaxy before space telescopes would be little more than a smudge compared to modern photos, right? Maybe not. One of the most famous pictures of our galactic neighbor was taken in — no kidding — 1888. The astronomer/photographer was Isaac Roberts , a Welsh engineer with a keen interest in astrophotography. Around 1878, he began using a 180 mm refracting telescope for observations, and in 1883, he began taking photographs. He was so pleased with the results that he ordered a reflecting telescope with a 510 mm first-surface mirror and built an observatory around it in 1885. Photography and optics back then weren’t what they are now, so adding more mirrors to the setup made it more challenging to take pictures. Roberts instead mounted the photographic plates directly at the prime foc...

If you ever built a line following robot, you’ll be nostalgic about [Jeremy’s] light-seeking robot . It is a very simple build since there is no CPU and, therefore, also no software. The trick, of course, is a pair of photo-sensitive resistors. A pair of motors turns the robot until one of the sensors detects light, then moves it forward. This is a classic beginner project made even easier with a 3D printer and PCB to hold the components. You might consider using an adjustable resistor to let you tune the sensitivity more easily. In addition, we’ve found that black tubes around the light sensors in this sort of application give you a better directional reading, which can help. The robot only has two wheels, but a third skid holds the thing up. A freely-rotating wheel might work better, but for a simple demonstration like this, the skid plate is perfectly fine. This is a good reminder that not every project has to be fantastically complex or require an RTOS and high-speed multi-...

How do you go about making a mirror with 128 segments, each of which can be independently angled? That was the question that a certain bloke over at [Time Sink Studio] found himself pondering on , to ultimately settle on a whole batch of mini-actuators bought through AliExpress. These stepper-based actuators appear to be akin to those used with certain Oppo smartphones with pop-up camera, costing less than half a dollar for a very compact and quite fast actuator. The basic design is very much akin to a macro version of a micromirror device , as used in e.g. DLP projectors, which rely on a kinetic mirror mount to enable precise alignment. With the small actuators travelling up to 8 mm each, the mirrors can cover 73 mm at a distance of 4 meters from a wall. With the required angle of the mirror being effectively just the application of the Pythagorean theorem, the biggest challenge was probably calibrating these linear motors. Since they’re open loop devices, they are zeroed much li...

Syringes are pretty ergonomic, but when manually dispensing flux and solder paste it doesn’t take long before one wants a better way. [Elektroarzt]’s flux and solder paste dispenser design uses 3D-printed parts and minimal hardware (mostly M3x20 screws, and an optional spring) to improve handling and control. The operating principle is very similar to how a hot glue gun feeds a stick of glue. How does it work? The ratcheting lever mechanism is similar to that of a hot glue gun, where an arm slips into notches in a rod when pressed down, driving it forward and never backward. In the process, a larger lever movement is translated into a shorter plunger travel, enhancing control. The types of syringes this tool is meant to be used with have a plunger tip or piston (the rubber stopper-looking part, in contact with the liquid) inside the loaded syringe, but no plunger shaft attached to it. This is common with syringes meant to be loaded into tools or machines, and [Elektroarzt]’s too...

Get a handle on this bad boy! Okay, so those voids are really more for airing out your palms, I’d imagine, because palm sweat sure is real — you should see the pads of my Kinesis. This kind of looks like two sawed-off machine guns kissing, and I mean that in the best possible and non-violent way. Image by [ntc490] via reddit So, [ntc490] has been on Team Special Keyboard for eight years now and decided it was time to design one. The goal was to make something semi-portable, super ergo, and as easy/cheap to build as possible, which, honestly, that sounds like one of those pick-two situations. And yet, pricing (oh yeah, this is gonna be A Thing You Can Buy) will be around $115-155, depending upon whether you want the base kit, or the add-ons, too, minus switches and key caps. So let’s get into the particulars here. As you can see, there are key wells and thumb clusters, inspired by other keyboards including your bog standard Maltrons, Kinesis Advantages and more modern, open-sourc...

For switching high-powered loads from a microcontroller, or for switching AC loads in general, most of us will reach into the parts bin and pull out a generic relay of some sort. Relays are fundamental, proven technologies to safely switch all kinds of loads. They do have their downsides, though, so if you need silent operation, precise timing, or the ability to operate orders of magnitude more times you might want to look at a triac instead. These solid state devices can switch AC loads unlike other transistor-based devices and [Ray] at OpenSprinkler is here to give us an overview on how to use them . The key to switching an AC load is bi-directional conductivity. A normal transistor or diode can only conduct in one direction, so if you try to switch an AC load with one of these you’ll end up with what essentially amounts to a bad rectifier. Triacs do have a “gate” analogous to the base of a bipolar junction transistor, but the gate will trigger the triac when current flows in eithe...

Looking for a unique vacation spot? Have at least $10 million USD burning a hole in your pocket? If so, then you’re just the sort of customer the rather suspiciously named “GRU Space” is looking for. They’re currently taking non-refundable $1,000 deposits from individuals looking to stay at their currently non-existent hotel on the lunar surface. They don’t expect you’ll be able to check in until at least the early 2030s, and the $1K doesn’t actually guarantee you’ll be selected as one of the guests who will be required to cough up the final eight-figure ticket price before liftoff, but at least admission into the history books is free with your stay. This never happened. The whole idea reminds us of Mars One, which promised to send the first group of colonists to the Red Planet by 2024 . They went bankrupt in 2019 after collecting ~$100 deposits from more than 4,000 applicants, and we probably don’t have to tell you that they never actually shot anyone into space. Admittedly, ...

When [Electron Impressions] used a powerful ultrasonic array to project a narrow beam of sound toward a target, he described it as potentially useful in getting someone’s attention from across a crowded room without disturbing other people. This is quite a courteous use compared to some of the ideas that occur to us, and particularly compared to the crowd-control applications that various militaries and police departments put directional speakers to. Regardless of how one uses it, however, the physics behind such directional speakers is interesting. Normal speakers tend to disperse their sound widely because the size of the diaphragm is small compared to the wavelength of the sound they produce; just like light waves passing through a pinhole or thin slit, the sound waves diffract outwards in all directions from their source. Audible frequencies have wavelengths too long to make a handheld directional speaker, but ultrasonic waves are short enough to work well; [Electron Impressions...