Today, acronyms such as PAL and initialisms such as NTSC are used as a lazy shorthand for 625 and 525-line video signals, but back in the days of analogue TV broadcasting they were much more than that, indeed much more than simply colour encoding schemes. They became political statements of technological prowess as nations vied with each other to demonstrate that they could provide their citizens with something essentially home-grown. In France, there was the daddy of all televisual symbols of national pride, as their SECAM system was like nothing else. [Matt’s TV Barn] took a deep dive into video standards to find out about it with an impressive rack of test pattern generation equipment.
At its simplest, a video signal consists of the black-and-while, or luminance, information to make a monochrome picture, along with a set of line and frame sync pulses. It becomes a composite video signal with the addition of a colour subcarrier at a frequency carefully selected to fall between harmonics of the line frequency and modulated in some form with the colour, or chrominance, information. In this instance, PAL is a natural progression from NTSC, having a colour subcarrier that’s amplitude modulated and with some nifty tricks using a delay line to cancel out colour shifting due to phase errors.
SECAM has the same line and frame frequency as PAL, but its colour subcarrier is frequency modulated instead of amplitude modulated. It completely avoids the NTSC and PAL phase errors by not being susceptible to them, at the cost of a more complex decoder in which the previous line’s colour information must be stored in a delay line to complete the decoding process. Any video processing equipment must also, by necessity, be more complex, something that provided the genesis of the SCART audiovisual connector standard as manufacturers opted for RGB interconnects instead. It’s even more unexpected at the transmission end, for unlike PAL or NTSC, the colour subcarrier is never absent, and to make things more French, it inverted the video modulation found in competing standards.
The video below takes us deep into the system and is well worth a watch. Meanwhile, if you fancy a further wallow in Gallic technology, peer inside a Minitel terminal.
Remember learning to tie your shoes or ride a bike? Like many things, that’s easy once you know how to do it, but seems impossible before you learn. [NovaSpirit] asserts that Freecad is simple, and provides a simple walkthrough to create a part in the video below.
If this were riding a bike, this tutorial would be akin to watching someone ride a bike to pick up tips. You’d probably still want to have someone explain details to you before you attempt it yourself.
Building with LEDs is a hacker pastime like no other – what’s more, if you keep playing with LED tech out there, you’re bound to build something elegant and noteworthy. For today’s fix of beautiful LED devices, take a look at the two LÄMP creations of [Jana Marie], both LED projects building upon one another. It’s not just your regular RGB LEDs – she adds a healthy mix of white and yellow LEDs, making for colors way more natural-looking and pleasant to the eye!
The first one is the LAEMP-Panel, a two-PCB sandwich, combining into a spot light you can use for any purpose where some extra LED would really shine – be it photography, accent, or mood lighting. All of these LEDs are individually controlled and from the SK6812 family, half of them YYW and half RGB variation. As for the base board, the controller is an ESP32, paired to an E75 ZigBee module – this spot light is built to be part of your home’s ZigBee network. If you look at the base board’s KiCad files, you will also notice six-pin headers on five edges – and they’re there for a reason.
The sister project to this one, the LAEMP-Prism, is a remarkable hexagonal lamp built upon the LAEMP-Panel’s PCB base, but in a desk-friendly form-factor. Six extra side panels with a generous amount of circular cutouts give you a total of 291 LEDs, mix of yellow, white and RGB as before – we got to say, from the pictures we found, it looks like a gorgeous thing to have in your house!
Such is a story of building a spotlight and a desk lamp, both using the same hardware base to accomplish quite different purposes. As is [Jana-Marie]’s tradition, these two lamps are fully open-source, complete with instructions on assembling them – everything is ready for you if you’d like to build one of your own, whichever version it may be! When it comes to lamp-building projects that excel at looks, one can’t forget the two other lamps we’ve seen a few years ago – one built with fiber optics, and another in the shape of the Moon.
Photographic enthusiasts will invariably amass an extensive collection of lenses, and in their communities there are near-mythical and sought-after lenses that change hands for incredible prices. It’s probably the oldest photographic adage though, that the best camera in the world is the one in your hand when the scene presents itself, and probably one of the simplest cameras in the world remains the disposable film camera. Their tiny plastic lenses are not in the same league as the pricey ones, but can they be used by a more serious photographer? [Volzo] set out to find out.
Disposable cameras aren’t the most environmentally friendly items, and he rightly points out that a cheap compact camera can deliver the same in a more sustainable package. There’s also the point to make that the flash capacitor if it has one can deliver a nasty shock, but once past that it’s easy to remove the lens itself.
A single element lens brings with it some significant distortion, and it’s a surprise to find that the focal plane of a disposable camera is curved to take account of that. His first 3D printed mount and adapter for a Sony mirrorless compact camera uses a small aperture to reduce the distortion effects from the edge of the lens but he’s not out of tricks yet. Using a pair of the lenses back-to-back he halves the focal length but further corrects the distortion and delivers a consequent wider angle. Take a look, in the video below.
The result is a usable lens for the toy-camera look on your digital camera, and since the files can all be found at the link above it’s something you can try too. If a disposable camera comes our way, we certainly will.
We like to think that most common electronic components are essentially commodity items. We don´t buy premium wire or resistors. You just assume these electronic components are more or less the same from anywhere unless you need some very special characteristics. What about fuses? We would assume they are all essentially the same, but [Ham Radio A2Z] says he’s throwing away his generic fuses after he found they didn’t work as he would expect.
Of course, name-brand fuses are tested to very specific tests, and you get to see the plots of how the fuses are supposed to melt for Bussmann fuses. Then he takes out a generic assortment of fuses he bought at a hamfest. No Bussmann fuses in that batch!
Comparing the generic fuses with some from Bussmann and Littlefuse, they all work fine to carry current. That isn’t the problem. The problem is when you feed the fuses 20 A and expect them to clear. A 5 A generic fuse carried over 20 A for a very long time, and, as you might expect, it got very hot. We kept waiting for the fuse to blow, but after three minutes, he gave up.
For comparison, a 10 A Bussmann fuse in the same conditions blew almost immediately — about 350 milliseconds. None of the generic fuses blew, and, in fact, the fuse in the video had been subjected to 20 A of over-stress several times already. It seems like it is nearly impossible to blow them at that current level despite it being four times the marked current. Not much of a bargain.
As the video points out, fuses aren’t as much to protect your equipment as much as they are to prevent fires, so don’t forget to include them even on simple projects. Remember the TI 99/4A? The power supply for that vintage computer has an odd little box in the power cable very near the plug. Why? Because they forgot to put a fuse in until the UL reminded them.
To say that desktop 3D printing had a transformative effect on our community would be something of an understatement. In just a decade or so, we went from creaky printers that could barely extrude a proper cube to reliable workhorses that don’t cost much more than a decent cordless drill. It’s gotten to the point that it’s almost surprising to see a project grace these pages that doesn’t include 3D printed components in some capacity.
There’s just one problem — everything that comes out of them is plastic. Oh sure, some plastics are stronger than others…but they’re still plastic. Fine for plenty of tasks, but certainly not all. The true revolution for makers and hackers would be a machine that’s as small, convenient, and as easy to use as a desktop 3D printer, but capable of producing metal parts.
If Cooper Zurad has his way such a dream machine might be landing on workbenches in as little as a month, thanks in part to the fact that its built upon the bones of a desktop 3D printer. His open source Powercore device allows nearly any 3D printer to smoothly cut through solid metal using a technique known as electrical discharge machining (EDM). So who better to helm this week’s Desktop EDM Hack Chat?
You know how it goes. You’re working on a project, and you need to do some ultra-precise probing, so you end up making a custom PCB probing octopus along the way. Or you find that you spend more time making the jig to hold down a part for machining than you do machining it. Hackers are not merely a tool-using species, we’re a tool-making species – it’s in our nature to want to build the tools that make it easier to get the job done.
The Gearing Up round of the Hackaday Prize celebrates the tool makers. If you’ve got a project that maybe isn’t an end in itself, but rather one of those utility project that can make all the difference, we want to see it here. Maybe it’s obscure measurement gear, maybe it’s a test rig or a bolt sorter, maybe you’ve built your own reflow hot plate. This is the challenge round for you!