Bear with us for a moment for a little background. The Rideau Canal Skateway in Ottawa is the world’s largest natural skating rink, providing nearly 8 km of pristine ice surface during the winter. But maintaining such a large ice surface is a challenge. A regular Zamboni can’t do it; the job is just too big. So the solution is a custom machine called the Froster, conceived by Robert Taillefer and built by Sylvain Fredette.

A patent was filed in 2010, granted by the Canadian Intellectual Property Office, and later lost because important notifications started going to an apparently unchecked spam folder. The annual fee went unpaid, numerous emails went unanswered, an expiry date came and went, and that was that.

It’s true that emailed reminders (the agreed-upon — and only — method of contact) going unnoticed to spam was what caused Robert to not take any action until it was too late. We’d all agree that digital assistants in general need to get smarter, and that includes being better at informing the user about automatically-handled things like spam.

But what truly cost Robert Taillefer his patent was having a single point of failure for something very, very important. The lack of any sort of backup method of communication in case of failure or problem meant that this sad experience was, in a way, a disaster just waiting to happen. At least that’s how the Federal Court saw it when he took his complaint to them, and that’s how they continued to see it when he appealed the decision.

If you’ve never heard of the Rideau Canal Skateway or would like to see the Froster in action, check out this short video from the National Capital Commission of Canada, embedded just under the page break.

Ink stamps can be fun to make and use, and 3D printers are uniquely positioned to create quality stamps of all kinds with just a little care. As with most things, the devil is in the details and the best results will require some extra work. Luckily, [Prusa] has a blog post that goes through how to 3D print the best stamps and includes concrete recommendations and tips to get the most out of the process.

What makes a good 3D-printed stamp? It should be easy to use, transfer an image cleanly, and retain ink reasonably well. To hit these bases, printing the stamp face out of a flexible material is probably the most important, but a flat and smooth stamp surface is equally crucial. Satin-finish build plates will give a weathered look to the stamp, but textured build plates in general are no good.

As for the design, turning an image into a 3D object can be a bit challenging for novices, but there are tools that make that much easier now than it used to be. Some slicers allow importing .svg files (scalable vector graphics) with which to emboss or deboss objects, and online tools as well as free software like Inkscape will let folks covert images into .svg format.

Flexible filaments tend to be stringy so they should be dried before use, especially if the stamp design has a lot of separate elements that invite stringing. Any flex filament should do the job, but of course some specific filament brands perform better than others. Check out the full blog post for specific recommendations.

The remaining tricky element is that flexible filaments also tend to be poor at bridging, and if one is printing a stamp face-down on the build plate (to get that important, ultra-flat face) then the upper inside of the stamp may need some support for it to come out right. As [Prusa] suggests, this is a good place to use a manual, drop-in pre-printed support piece. Or if one has the ability to print in multiple materials, perhaps print the support structure in PLA since it is just about the only material that won’t completely weld itself to flex filaments. Of course, if one is designing the stamp entirely in CAD, then the best option would be to chamfer the stamp elements so supports aren’t necessary in the first place. Finally, don’t overlook the value of a physical design that makes handling easy and attractive.

Since 3D printing makes iteration so fast and easy, maybe it would be worth using this to revisit using rubber stamps to help create PCBs?

At the recent 38C3 conference in Germany, someone gave a talk about sending TOSLINK digital audio over fiber optic networks rather than the very low-end short distance fibre you’ll find behind hour CD player. This gave [Manawyrm] some ideas, so of course the IP-over TOSLINK network was born.

TOSLINK is in effect I²S digital audio as light, so it carries two 44.1 kilosamples per second 16-bit data streams over a synchronous serial connection. At 1544 Kbps, this is coincidentally about the same as a T1 leased line. The synchronous serial link of a TOSLINK connection is close enough to the High-Level Data Link Control, or HDLC, protocol used in some networking applications, and as luck would have it she had some experience in using PPP over HDLC. She could configure her software from that to use a pair of cheap USB sound cards with TOSLINK ports, and achieve a surprisingly respectable 1.47 Mbit/s.

We like this hack, though we can see it’s not entirely useful and we think few applications will be found for it. But she did it because it was there, and that’s the essence of this game. Now all that needs to happen is for someone to use it in conjunction with the original TOSLINK-over network fiber, for a network-over-TOSLINK-over-network abomination.

If you’ve owned a CD player or other piece of consumer digital audio gear manufactured since the 1980s, the chances are it has a TOSLINK port on the back. This is a fairly simple interface that sends I²S digital audio data down a short length of optical fibre, and it’s designed to run between something like a CD player and an external DAC. It’s ancient technology in optical fibre terms, with a lowish data rate and plastic fibre, but consider for a minute whether it could be adapted for modern ultra-high-speed conenctions. It’s what [Ben Cartwright-Cox] has done, and he delivered a talk about it at the recent 38C3 event in Germany.

if you’ve cast you eye over any fibre networking equipment recently, you’ll be familiar with SFP ports. These are a standard for plug-in fibre terminators, and they can be had in a wide variety of configurations for different speeds, topographies, and wavelengths. They’re often surprisingly simple inside, so he wondered if he could use them to carry TOSLINK instead of a more conventional network. And it worked, with the simple expedient of driving an SFP module with an LVDS driver to make a differential signal. There follows a series of experiments calling in favours from friends with data centre space in various locations around London, finally ending up with a 140 km round trip for CD-quality audio.

It’s an interesting experiment, but perhaps the most value here is in what it reveals to us about the way optical networking systems work. Most of us don’t spend our days in data centres, so that’s an interesting technology to learn about. The video of the talk itself is below the break.

Modern remote control (RC) radios are capable of incredible range, but they’re still only made for line-of-sight use. What if you want to control a vehicle that’s 100s of kilometers away, or even on the other side of the planet? Cellular is an option, but is obviously limited by available infrastructure — good luck getting a cell signal in the middle of the ocean.

But what if you could beam your commands down from space? That’s what [Thingify] was looking to test when they put together an experimental RC boat using a Starlink Mini for communications. Physically, there was no question it would work on the boat. After all, it was small, light, and power-efficient enough. But would the network connection be up to the task of controlling the vehicle in real-time?

During early ground testing, the Mini version of the Starlink receiver worked very well. Despite being roughly 1/4 the size of its predecessor, the smaller unit met or exceeded its performance during benchmarks on bandwidth, latency, and signal strength. As expected, it also drew far less power: the Mini’s power consumption peaked at around 33 watts, compared to the monstrous 180 W for the larger receiver.

On the water, there was even more good news. The bandwidth was more than enough to run a high-resolution video feedback to the command center. At the same time, the boat moved autonomously between waypoints, and when [Thingify] switched over to manual control, the latency was low enough not to be a problem. We wouldn’t recommend manually piloting a high-speed aircraft over Starlink, but for a boat that’s cruising along at 4 km/h, the lag didn’t even come into play.

The downside? Starlink is a fairly expensive proposition; you’d need to have a pretty specific mission in mind to justify the cost. The Mini receiver currently costs $599 USD (though it occasionally goes on sale), and you’ll need at least a $50 per month plan to go with it. While this puts it out of the price range for recreational RC, [Thingify] notes that it’s not a bad deal if you’re looking to explore uncharted territory.

BLiiNK is an AI-powered app that helps promote good eye health and posture while using your computer. BLiiNK reminds you to blink regularly to reduce the risk of dry eyes. It works by counting your blinking rate and notifies you if it falls below the recommended level of 12 blinks per minute. The notification then […]

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