Kritik sah

The first known use of humans using wind to perform mechanical work with machines dates back to ninth-century Persian windmills. But if we count sailing vessels among those machines, the history goes back to sometime just before the invention of written language. Since then, humans have been sailing everything from the tiniest of Sunfish to the largest of shipping vessels, and even sailing boats like canoes that aren’t typically designed for efficient sailing. For those who already own a canoe, the conversions can be straightforward but often involve drilling into the hull. This homemade conversion kit, on the other hand, requires no drilling at all . The first, and most obvious, part of the conversion is to add a mast and sail. [Tea]’s primary setup does involve drilling a mast thwart into the gunwales of the canoe, but he also built an alternative setup which clamps to the gunwales and the bow deck instead. The standing lug sail is then hoisted on an unstayed wooden m...

We’re all used to satellite navigation systems such as GPS or GLONASS, sheer magic in which the combination of a set of reference transmitters and super-accurate timing information can be used to calculate a position to an astounding precision. They had land based predecessors such as LORAN and Decca Navigator which worked in a similar fashion but with fixed land-based reference transmitters. Terra is an attempt to do the same thing without a network of dedicated transmitters , instead using FM broadcast transmitters as its fixed points. This might seem like an impossible task without access to the transmitters, but they have a workaround using the Internet as a backhaul. Instead of transmitting their timing information like the systems mentioned above, they rely on a set of reference receivers sharing it online to the client’s receiver software. So far they have a demo running in Denver. The interesting thing about this system is that it’s open-source, and requires ...

This week Jonathan chats with Andy Gryc and Aaron Basset about QNX, and the interesting Open Source history and future of that embedded OS. Why does QNX Everywhere feel more open, and why do you need to register an account to download images? All that and more — Watch to find out! Open-source Dashboard: https://oss.qnx.com/ GitHub Repository: https://github.com/qnx-ports QNX Everywhere webpage: https://qnx.software/en/developers/get-started/qnx-everywhere 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 Comm...

We all love a good bit of bounce now and then, with everything from trampolines to bouncy castles and bouncy balls forming the staple of a wholesome childhood for many. That said, most of our bouncy experiences in day to day life concern bouncy objects that meet immovable or rigid objects, including said child having a blast in a bouncy castle. Where the physics get arguably more interesting and less intuitive is when you combine two objects that are both bouncy, with [Steve Mould] recently taking a look at the tuning of said bounciness to even kill the bounce completely. Understanding how to achieve this tuning means understanding how the kinetic energy is stored in each flexible material, and how to dissipate it in a way that doesn’t result in the aforementioned bounciness. In the simple physical demonstration setup the addition or removal of weights to the lower sprung platform tunes the response to the bouncy ball that is dropped on top of it. After going through the scienc...

Laser diodes are convenient light sources, but for precise optical work their often-elliptical beam profile leaves something to be desired. One way to get around this is to couple the beam into a single-mode optical fiber, which then emits a circular Gaussian beam from the other end. For more advanced experiments, therefore, [Diffraction Limited] built this fiber-coupled laser source . The simplest approach is to place the fiber directly against a light source, but this results in most of the light missing the three-micron fiber core. Optical fibers have an acceptance cone, and only light approaching from within this cone is coupled into the fiber. The design therefore uses an aspheric lens to focus light from the laser diode down to a tiny point matching the diameter of the fiber core, creating a cone of incoming light narrower than the acceptance cone. The body of the laser source was CNC machined out of brass, with the laser-diode press-fit in one end. The lens stands in front of...

The phenomenon of cable-shaped indents in the plastic cases of retro systems is one that’s probably painfully familiar to many a collector of such systems. Although in these situations neither side got hot enough to cause any melting – especially while disconnected in storage – it still has that same melted appearance. The real cause here is not heat, but plasticizer migration, as detailed in a recent video by [Run Stop Restored] over on YouTube. Plasticizers are an additive to many plastics that aim to make it more flexible (‘plastic’), as well as improve other characteristics of the base material, with PVC in particular relying on plasticizers to give it its desired properties for applications where PVC has to be flexible. Here the flexible cable insulation of these devices generally uses PVC, which over time can migrate to other polymers when brought into close contact for extended periods of time. The – usually ABS – enclosures of e.g. C...