Posts

Featured Post

A TV Transmitter From An STM32

-
Image
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...
Post a Comment
Get this one»

Keebin’ with Kristina: the One With the Uni-body That Does the Splits

-
Image
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...
Post a Comment
Get this one»

How to Restore your 19th-Century Lancashire Boiler to Hold 120 PSI

-
Image
The Industrial Revolution was powered by steam, with boilers being a crucial part of each steam engine, yet also one of the most dangerous elements due to the high pressures involved. The five Lancashire boilers at the Claymills Pumping Station are relatively benign in this regard, as they operate at a mere 80 PSI unlike e.g. high-pressure steam locomotives that can push 200 – 300 PSI. This doesn’t mean that refurbishing one of these boilers is an easy task and doesn’t involve plugging a lot of leaks, as the volunteers at this pumping station found out . At this Victorian-era pumping station there are a total of five of these twin-flue Lancashire boilers , all about 90 years old after a 1930s-era replacement , with them all gradually being brought back into service. The subject of the video is boiler 1, which was last used in 1971 before the pumping station was decommissioned . Boilers 2 and 3 were known to be in a pretty bad condition, and they needed a replacement for boiler 5 as i...
Post a Comment
Get this one»

X-Ray a PCB Virtually

-
Image
If you want to reverse engineer a PC board, you could do worse than X-ray it.  But thanks to [Philip Giacalone], you could just take a photo, load it into PCB Tracer , and annotate the images. You can see a few of a series of videos about the system below. The tracer runs in your browser. It can let you mark traces, vias, components, and pads. You can annotate everything as you document it, and it can even call an AI model to help generate a schematic from the net list. This is one of those things that you could do without. Any photo editor could do the same thing. But having the tool aware of what the photo is showing makes life easier. The built-in features are free, but if you use the AI tool, he says it will cost you about a half-dollar per schematic (paid to the AI company). Even if you don’t think you need to reverse-engineer anything, you may still find this useful if you are trying to understand a board for repair. We’ve had a good Supercon/Remoticon talk about PCB rev...
Post a Comment
Get this one»

ATABoy is an Open Source USB Bridge For Old IDE Drives

-
Image
You can get an IDE to USB bridge from all the usual sources, but you may find those fail on the older drives in your collection– apparently they require drives using logical block addressing, which did not become standard until the mid-1990s. Some while some older drives got in on the LBA game early, you were more likely to see Cylinder-Head-Sector (CHS) addressing. That’s why [JJ Dasher], a.k.a [redruM0381] created ATABoy, an open-source IDE bridge that can handle the oldest drives that fit on the bus. The heart of the build is an RP2350, which serves as both IDE and USB host controller. To computer, after a little bit of setup, the drive attached to ATABoy shows up as a regular USB mass storage device. A little bit of setup is to be expected with drives of this vintage, you may remember. Luckily [JJ] included a handy BIOS-themed configuration utility that can be accessed through any serial console. He says you’ll usually be able to get away with “Auto Detect & Set Geometry,” b...
Post a Comment
Get this one»

Tech In Plain Sight: Projection Clocks

-
Image
You wake up in the middle of the night. Is it time to get up? Well, you can look at the nightstand clock. Unless your partner is in the way. Whoops. Even then, without your glasses, the time is just a fuzzball of light. You could ask Alexa, but that’s sure to wake your partner, too. The answer is a projection clock. In its modern form, it shoots a digital time display on a wall or ceiling with digits so large that you don’t need your glasses. If you can see the ceiling, you can tell what time it is. New Tech A modern invention, of course. No, not really. According to [Roger Russel], a UK patent in 1909 used an analog clock face and lightbulbs to project the clock face and hands on the ceiling. Unfortunately, [Roger’s] website is no more, but the Wayback Machine is on the job . You can see a device of the same type at the British Museum . A modern projection clock on the ceiling. In 1938, [Leendert Prins] filed for a patent on a similar projection clock . Sometimes known as “ceil...
Post a Comment
Get this one»

Running in Printf

-
Image
You may or may not know, but printf is a Turing-complete language, once you exploit all the strange and wonderful format characters in it (especially %n). But who has time to write code as printf modifiers? Now, thanks to [sebsite], you can at least write in a slightly higher level assembly language and compile to printf . Practical? No. Cool? Undeniably. As an example, the page shows fizzbuzz written in the assembler: <pre><code>alias i, fizz, buzz ->fizz ([i] + 1) % 3 == 0 ->buzz ([i] + 1) % 5 == 0 ->i [i] + 1 ->exit [i] == 100 [i] if !![i] & ![fizz] & ![buzz] "Fizz" if [fizz] "Buzz" if [buzz] "\n" if [i]</code></pre> <pre> The alias keyword defines constants and, owing to default values, sets i to zero, fizz to one, and buzz to 2. The “arrow” statements store a result into a variable (so the first assignment sets the resulting value into fizz). You need C23 to compile the assembler. Good luck tr...
Post a Comment
Get this one»