This Block Of Rubber Can Count To Ten

July 6, 2023 by 19 Comments

Complex behaviors can arise from simple mechanics, and that’s demonstrated by a block of rubber that acts as a counter.

The block contains beams, and by controlling how the block is compressed, the vertical beams shift in a stable and consistent way, acting as a mechanical counter. It’s a straightforward implementation of the work of two physicists from the Netherlands: [Martin van Hecke] and [Lennard Kwakernaak].

This device brings flexures to mind, which are also examples of obtaining complex and useful behavior from seemingly simple objects. We’ve seen flexures used as latches and counters, and we’ve seen 3D printed flexures as a kind of linear actuator.

You can check out the research paper for more details on the rubber beam counter. [Kwakernaak] aims to create a much more complex structure with elements that interact across a plane instead of in a single direction. Such a device would, in effect, be a simple computer.

Watch the beam counter in action in the short video embedded below. See how the elements of the green rubber block move while constrained by an outer frame that helps control the force that is applied. The thin beams flip from left to right, one at a time with each press.

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Tentacle Robot Is Like An Elephant Trunk

July 6, 2023 by 1 Comment

It sounds like bad science fiction or anime, but researchers are creating helical-artificial fibrous muscle structured tubular soft actuators. What? Oh, tentacle robot arms. Got it.

The researchers at Westlake University in China found inspiration in elephant trunks. Elephant trunks are entirely devoid of bone but use a tubular muscle structure. By deforming certain muscles, complex motion is possible. After understanding how they work, it was just a matter of making a similar structure from artificial muscle fibers.

The resulting actuator uses smart materials and has eleven different morphing modes — more than other attempts to build similar structures. The fabrication sounds difficult, it involves stretching chemically reactive materials over a form with specific winding angles.

The fibers react to light. Depending on the configuration, the stalk can seek light or avoid light. We were hoping the “Materials and Methods” section would give some ideas of how to do this ourselves, but it looks like you’d need some uncommon liquid crystal materials, and you’d also have to work out some of the details.

Animatronic tentacles are usually complex cable affairs. However, we have seen some soft robots in the past, too.

System Essentially Contradicting American Methods

July 5, 2023 by 36 Comments

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.

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FreeCAD Is Simple, According To This Tutorial

July 5, 2023 by 44 Comments

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.

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Two lamp versions side by side - one desk lamp and one spotlight lamp, both turned on and shining

A Tale Of Two LÄMPs

July 5, 2023 by 4 Comments

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.

Probably The Cheapest Lens You Will Ever Use

July 5, 2023 by 23 Comments

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.

This isn’t the first disposable camera lens project we’ve brought you.

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A Fuse Is Just A Fuse, Right?

July 5, 2023 by 39 Comments

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.

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