Kritik sah

The timer mechanism of the Vend-o-Vision. (Credit: SpaceTime Junction, YouTube) There was a time before portable TVs and personal media players when the idea of putting coin-operated TVs everywhere, from restaurants to airports and laundromats, would have seemed like a solid business model. Thus was born the Vend-o-Vision by Mini-TV USA, which presented itself as a cash earner for businesses and a way to make their customers even happier. One of these new-in-box units recently made its way over to [Mark] of the  SpaceTime Junction YouTube channel. This unit is very simple, with what appears to be an off-the-shelf Panasonic black-and-white TV with UHF and VHF reception capability, inside a metal box that contains the timer mechanism, which is linked to the coin mechanism. Depending on a physical slider with three positions, you get anywhere from 10 to 20 minutes per quarter, with the customer having to tune into the station themselves using the TV’s controls. A counter m...

At first glance, it may look like [Rybitski]’s 7-segment RGB LED clock is something that’s been done before, but look past the beautiful mounting. It’s not just stylishly framed; the back end is just as attentively executed. It’s got a built-in web UI, MQTT automation, so Home Assistant integration is a snap, and allows remote OTA updates, so software changes don’t require taking the thing down and plugging in a cable. A slick web interface allows configuring which LEDs belong to which segments without code changes. Pixel Clock is code for the Wemos D1 Mini microcontroller board and WS2812/WS2812B RGB LED strips, but it’s made to be flexible enough to support different implementations. For example, altering which LEDs in the strip belong to which segments on which digits can be configured entirely from the web interface. Naturally, one could build an LED strip clock using the same layout [Rybitski] did and require no changes at all — but it’s very nice to see that different wir...

Picture this: you have an irregular opening you need to fabricate a piece to fill. Maybe it’s the stonework of a fireplace; maybe it’s the curved bulkhead of a ship. How do you get that shape? The most “Hackaday” answer would be to 3D scan the area, create a CAD model based on the point cloud, and route the shape with CNC. Of course, none of those were options for the entirety of human history. So how do you do it if you don’t have such high-tech toys? With a stick , as [Essential Craftsman] takes great pains to show us in the video below. It’s not just any stick, of course. Call it a “tick stick”, a “speil stick”, or a “joggle stick” — whatever you call it, it’s just an irregularly shaped piece of wood. The irregular shape is key to the whole process. How you use it is simple: get some kind of storyboard — cardboard, MDF, whatever — that fits inside your irregular void. Thanks to the magic of the stick, it need not fit flush to the edges of the hole. You put the tick stick on the st...

Everyone is probably familiar with the concept of battery-powered devices, but generally, this involves a laptop with a beefy battery pack and hardware optimized for low power draw. You could also do the complete opposite and try to run a desktop PC off alkaline AA cells, as [ScuffedBits] recently did out of morbid curiosity . Exactly how many alkaline cells does it take to run a desktop PC for any reasonable amount of time? One nice thing about using batteries with a desktop PC is that you can ditch the entire AC-DC power conversion step and instead use a DC-DC adapter like the well-known PicoATX and its many clones. These just take in 12 VDC and tend to have a fairly wide input voltage range, which is useful when your batteries begin to run out of juice. In this case, just above 10 VDC seemed to be the cut-off point for the used DC-DC adapter. In the end, [ScuffedBits] used what looks like 56 alkaline AA cells connected in both parallel and series, along with two series-connected ...

Philco was a common household brand for many years. The company started in 1892, making street lights. Then they pivoted to batteries. This was big business when early radios were all battery-operated. But in the 1920s, line-powered radios threatened to shrink their customer base, so they pivoted again. This time, they started making radios. So what happened? [The Last Shift] has the story , and you can see the video below. Philco used advanced manufacturing techniques to make radios more affordable. By 1930, they were the number one radio maker in the world. After World War II, they moved into everything electric: mostly appliances, but also the new king of the electronics market, the television. Philco faced much competition and wanted to stand out. The answer was the Predicta, a TV like no other at the time. It used an advanced semi-flat picture tube with a plastic coating. The 17-inch or 21-inch picture tube was detached from the TV itself. In one model, the tube sat on top of ...

Having an AI assistant is all the rage these days, but AI assistants usually don’t know about your automation setups and may have difficulty dealing with tasks asynchronously. Enter zclaw . It gives you the option to have a personal assistant on an ESP32 backed by Anthropic, OpenAI, or OpenRouter. The whole thing fits in 888KB, and while it doesn’t host the LLM, it does add key capabilities to monitor and control devices connected to the ESP32. You communicate with the assistant via telegram. You can say things like “Remember the garage sensor is on GPIO 4.” Then later you might say: “In 20 minutes, check the garage sensor and if it is high, set GPIO 5 low.” It has an RTOS for scheduling tasks and is aware of the timezone and common periods. Memory persists across reboots, and you can pick different personas. Some of the use cases mentioned in the manual show how having something that can precisely schedule, control, or monitor devices might pay off. Ideas like bringing up a lab se...

Recently the Myrient game video archive announced that they’re shutting down on March 31st of this year, for a couple of reasons, but primarily the skyrocketing financial costs of hosting the archive. One advantage of Myrient over e.g. Archive.org is that – per the FAQ – every game on the site is curated and checked against a checksum of a known good copy. The site also focuses on fast downloads, making it a good resource if you’re trying to find ROMs of some more obscure old gaming system. Amidst the mourning it seems also pertinent to address the reasons behind this shutdown. Although finances are the main reason for this hobby project to be shut down, it’s due to (paywalled) download managers that  have recently appeared, and which completely bypass the donation requests and similar on the website. Despite use of Myrient for commercial, for-profit purposes having always been explicitly forbidden, this has been ignored to the point where the owner of Myrient had to shell ou...

2000 m above ground level (AGL), winds are stronger and much, much more consistent than they are at surface. Even if the Earth were a perfect sphere, there’d be a sluggish boundry layer at the surface, but since it’s got all these interesting bumps and bits and bobs, it’s not just sluggish but horribly turbulent, too. Getting above that, as much as possible, is why wind turbines are on big towers. Rather than build really big tower, Beijing Lanyi Yunchuan Energy Technology Co. has gone for a more ambitious approach: an aerostat to take power from the steady winds found at high altitude. Ambitiously called the Stratosphere Airborne Wind Energy System (SAWES) , the megawatt-scale prototype has recently begun feeding into the grid in Yibin, Sichuan Province. The name might be a bit ambitious, since its 2000 m test flight is only one tenth of the way to the stratosphere, but Yibin isn’t a bad choice for testing: as it is well inland, the S2000 prototype won’t have to contend with typhoon...

[Matt Denton]’s SpoolBot is a surprisingly agile remote-controlled robot that doesn’t just repurpose filament spool leftovers. It looks exactly like a 2 kg spool of filament; that’s real filament wound around the outside of the drum. In fact, Spoolie the SpoolBot looks so much like the real thing that [Matt] designed a googly-eye add-on, because the robot is so easily misplaced. The robot’s mass rotates around a central hub in order to move forward or back. SpoolBot works by rotating its mass around the central hub, which causes it to roll forward or back. Steering is accomplished by tank-style turning of the independent spool ends. While conceptually simple, quite a bit of work is necessary to ensure SpoolBot rolls true, and doesn’t loop itself around inside the shell during maneuvers. Doing that means sensors, and software work. To that end, a couple of rotary encoders complement the gearmotors and an IMU takes care of overall positional sensing while an ESP32 runs the show. ...

The WS2812B has become one of the most popular addressable LEDs out there. They’re easy to drive from just about any microcontroller you can think of. But what if you have a microcontroller at all? [Povilas Dumcius] decided to try and drive the LEDs with raw logic only. The project consists of a small board full of old-school ICs that can be used to drive WS2812Bs in a simplistic manner. A 74HC14 Schmitt trigger oscillator provides the necessary beat for this tune, generating an 800 kHz clock to keep everything in time and provide the longer pulse trains that represent logic one to a WS2812B. A phase-shifted AND gate generates the shorter pulses necessary to indicate logic zero. Meanwhile, a binary counter cycles through 24 bits (8 per R, G, and B) to handle color. Pressing each one of the three pushbuttons allows each color channel to be activated or deactivated as desired. It can make the strip red, green, or blue, or combine the channels if you press multiple buttons at once. That...

The Haxophone is an open source MIDI saxophone project that has achieved some popularity. It’s caught the attention of [Shieladixon] not because she is a saxophonist but because she plays the recorder and is dissatisfied with existing MIDI recorder peripherals. She’s set about modifying the device to produce the Haxocorder, a better MIDI recorder . The video below the break is the third of a series, of which part one and part two deal with the Haxophone and the shortcomings of her existing recorder peripheral. She’s replacing the Pi Zero of the Haxophone with a Pi Pico in a Zero form factor, and simplifying its design significantly to remove unnecessary features. The result is a versatile instrument capable at a touch of becoming the full range of recorders, which she demonstrates with some nifty duet work. The upstream Haxophone project can be found here if you are interested, and we hope she follows this up with a release of her mods to make the Haxocorder. Meanwhile if you fee...

There was a time when only the richest ham radio operators could have a radio with a panadapter. Back in the day, this was basically a spectrum analyzer that monitored a broad slice of the receiver’s intermediate frequency so you could see signals on either side of the receiver’s actual frequency. Today, with SDR technology and computers, this is an easy thing for receivers to implement. But what if you want to refit a classic radio? It isn’t that hard, and [Mirko Pavleski] shares his notes on how he tackled the project . You can also check it out in the video below. The plan is simple. A FET amplifier taps the radio’s IF stage before the first IF filter. This provides good isolation and buffering. Then, an emitter follower stage provides a matched output to the SDR through a low-pass filter. The SDR remains tuned to the IF frequency, of course. The rest is essentially software and procedures. Of course, your exact connection to your radio will differ unless you have the same recei...

Random numbers are very important to us in this computer age, being used for all sorts of security and cryptographic tasks. [Theory to Thing] recently built a device to generate random numbers using nothing more complicated than simple camera noise. The heart of the build is an ESP32 microcontroller, which [Theory to Thing] first paired with a temperature sensor as a source of randomness. However, it was quickly obvious that a thermocouple in a cup of tea wasn’t going to produce nice, jittery, noisy data that would make for good random numbers. Then, inspiration struck, when looking at vision from a camera with the lens cap on. Particularly at higher temperatures, speckles of noise were visible in the blackness—thermal noise, which was just what the doctor ordered. Thus, the ESP32 was instead hooked up to an OV3660 camera, which was then covered up with a piece of black electrical tape. By looking at the least significant bits of the pixels in the image, it was possible to pick up ...

If you want smooth top surfaces on your 3D printed parts, a common technique is to turn on ironing in your slicer. This causes the head to drag through the top of the part, emitting a small amount of plastic to smooth the surface. [Make Wonderful Things] asserts that you don’t need to do this time-consuming step. Instead, he proposes using statistical analysis to identify the optimal settings to place the top layer correctly the first time , as shown in the video below. The parameters he thinks make a difference are line width, flow ratio, and print speed. Picking reasonable step sizes suggested that there were 19,200 combinations of settings to test. Obviously, that’s too many, so he picked up techniques from famous mathematician [George E. P. Box] and also used Bayesian analysis to reduce the amount of printing required to converge on the perfect settings. Did it work? Judging from the video, it appears to have done so. The best test pieces looked as good as the one that used trad...

Climbing is a cool sport. With that said, like everything, it’s even better if you integrate lots of glowing colorful LEDs. To that end, [Superbender] worked up this fun climbing wall that features interactive lighting built right in. Structurally, there’s nothing too wild going on here. It’s a wood-framed climbing structure that stands 10 meters long and 2.5 meters high, and can be covered in lots of climbing holds. It’s the electronic side of things where it gets fun. An Arduino Due is installed to run the show, hooked up with a small TFT display and some buttons for control. It’s then hooked up to control a whole bunch of LEDs and some buttons which are scattered all across the wall. It’s also paired with an Arduino Nano which runs sound feedback, and a 433 MHz remote for controlling the system at a distance. [Superbender] uses the lighting for fun interactive games. One example is called  Hot Lava, where after each climbing pass, more holds are forbidden until you can’t mak...

BMX bikes are a unique frame geometry, essentially forgoing all travel efficiency for maneuverability and sturdiness. For how much abuse these bikes are designed to take, these are all good tradeoffs. But it turns out that these bikes also have an exceptionally low center of gravity, which could make them useful for drag racing, provided they’re given a suitably large electric motor and a few minor frame modifications . The project began as a fun weekend project for friends [Sam Barker] and [Tom Stanton]. They had a 20″ BMX wheel with a massive integrated hub motor that seemed to be begging to be put onto a BMX bike that they had on hand. After hooking up a 72V, 20Ah battery to it they were quickly zipping around the driveway, but the short wheelbase on the bike was bottlenecking its maximum performace because the bike would wheelie under high throttle. To solve that, they broke out the welder and extended frame, which kept the wheelies to a minimum and allowed them to take it out an...

If you know about Peltier modules, a solid-state fridge seems like an easy project. Pump 12V into the module, include a heat sink and a fan. Then you are done, right? According to [Peltier Power], this is not the way to design things , but it is common enough to give these units a reputation for failing quickly. The problem is that while it makes sense that an inefficient Peltier module needs more power to get more cooling. But the reality is in practical applications, many designs push the current up when it should be moving it down. The curve describes a parabola, and you can be on the high side or low side and still get the same result. But obviously, you don’t want to put in more current and get the same cooling that you could get with lower currents. According to the video, the mistake people make is pushing to a stable point to reach a cool point, then increasing the current until the chamber cools further. However, maintaining the cool doesn’t have to require a higher curren...

Analog TV may have shuffled off its mortal coil years ago, but there are still plenty of old CRT TV sets around that could receive it. [Kris Slyka] has just such a device, and decided to feed it something from an STM32 microcontroller . An STM32G431, to be precise, and he’s doing it using the on-chip hardware rather than in software. This unexpected feat is made possible by clever use of the internal oscillators and analog multiplexer. The video itself is generated using the MCU’s DAC, and fed into the on-board op-amp multiplexer which is switched at the VHF transmission frequency. This creates the required VHF TV transmission, but without audio. This component comes by abusing another peripheral, the internal RC oscillator for the USB. This is frequency modulated, and set to the required 5.5 MHz spacing from the vision carrier for the TV in question. It doesn’t (yet) generate the PAL color sub-carrier so for now it’s black and white only, but maybe someone will figure out a way. We...

Personally, I love a monoblock or uni-body split. You’ll pry this Kinesis Advantage from under my cold, dead hands. But on the go, I really like the Glove 80, a true split that can be completely wireless in case you want to put the halves really  far apart. Image by [thehaikuza] via reddit [thehaikuza] is the opposite, preferring a full split at the desk, but finding it troublesome when using it on the couch or at a cafe or co-working space, and so created dǎ bāo (打包) — a uni-body split that can also be a distant split. And this best-of-both worlds creation is remarkably [thehaikuza]’s first keyboard. The name means to take out food, and if you click the picture you can see a cute little take-out container on the silkscreen of the right half. Directly below it, there’s a track point nubbin to be used with the thumb. It does its split-in-half trick via a magnetic four-pin connector for when you want the halves stuck together. When the halves are separated, they can instead ta...