Troubleshooting Video Delay On The Raspberry Pi

The Raspberry Pi line of single-board computers are great little devices, and they can do great things with cameras and video. However, there can be a fair bit of latency involved in these tasks depending on the board you’re using and just what you’re doing. You need to have things set up just so to get peak performance. [MattKC] has tangled with this issue in a personal project, and recently had somewhat of a breakthrough.

The issue came up during [MattKC’s] work on cloning the WiiU gamepad. The idea was to receive the video stream from the WiiU console and display it using a Raspberry Pi Zero 2W. He had some problems with latency, wherein there was a strange 3 frames of latency in the video pipeline that just wouldn’t go away. Even substituting in some dummy frames into the pipeline and ignoring them at output time didn’t work—the latency stuck around. Eventually, [MattKC] realized the delay wasn’t about a certain number of frames—it was about time. About 50 milliseconds, in fact.

Drilling down further revealed that there was a problem in the way frames were being fed into and received from the decoder. The first frame would take about 50 ms to decode, while later frames would take far less—as little as 5ms. However, [MattKC’s] code wasn’t set up to grab frames as soon as they were done, so the lag carried forward. The video explains it in greater detail, and how polling the decoder regularly helped solve the issue. The final result was a Raspberry Pi Zero 2W that could process and display the WiiU video feed as quickly as the original Nintendo WiiU gamepad.

If you dug this, it’s worth going back and checking out where the WiiU gamepad project started, too. Video after the break.

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Tearing Down A Cheap Digital Caliper

Most hackers and makers end up with a cheap pair of calipers in the toolbox at some point or another. [DiodeGoneWild] decided to take a particularly cheap plastic pair and tear them down to see what makes them tick measure.

The electronics is, unsurprisingly, all contained inside the carriage which slides along the ruler. The ruler itself has an etched copper strip inside, underneath the scale sticker, with repetitive T-shaped sections. Meanwhile, the PCB in the carriage has a series of plates for capactive sensing. As the carriage slides along the copper strip inside the ruler, the capacitive sensing plates pick up varying capacitances which are directly proportional to how far the carriage has moved, allowing for precise measurement of relative position. Zeroing is a job for the user, via the ZERO button. We get to see how this works on the bare hardware level, and [DiodeGoneWild] even breaks out the oscilloscope to help show us what’s going on.

[DiodeGoneWild] also notes that these calipers are particularly frustrating for how quickly they discharge batteries while in storage. This may be down to the convenience feature, wherein moving the caliper switches the display on. There’s no hard off switch here—so the caliper is always drawing some juice even when it’s just in the cupboard. This is why these things are forever turning up dead when you need them.

If you’ve never pulled apart one of these cheap tools, this is a great way to see what’s actually going on under the hood. We’ve seen some other great teardowns lately, like this deep dive into a cheap pair of smartglasses. Video after the break.

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Bridging Older Tasmota Hardware Into Apple Home

The Tasmota firmware is a popular choice for flashing to a range of Espressif microcontrollers to turn them into smart home devices. If you have such devices in your house, you might wish they were easier to integrate with the Apple Home platform. As it turns out, though, there’s a convenient app for that.

[Christof Müller] built an app called Tasmoshelf for just this purpose. Its primary claim to fame is that it can easily help port a Tasmota-based setup into the Apple Home universe. It can achieve this without requiring a Home Assistant server or MQTT broker or any other workarounds. This is thanks to the fact that Apple Home is compatible with Matter technology, as are ESP32 devices running Tasmota 13 firmware or newer. They can natively jump on an Apple Home setup, and even act as a bridge for older ESP8266 devices that can’t speak Matter themselves. The device is able to run network scans to automatically discover devices and advise whether they can hook up directly to Apple Home, or whether a bridge is needed.

If you’re running Tasmota devices and want to easily integrate them, you might find Tasmoshelf a useful addition to your smart home setup. Just note that it does require a one-off purchase if you intend to use it beyond three devices, a limit which some might find somewhat restrictive.

We’ve looked at Tasmota in detail before; it’s a great way to whip up a smart home to suit your own desires. Meanwhile, if you’re whipping up your own nifty integrations, don’t hesitate to let us know on the tipsline.

Supercon Ten Tickets On Sale Now

Hackers, start your engines! We’re opening up ticket sales for our tenth, the 2026 Hackaday Supercon, to take place Nov 6-8 in Pasadena, CA. As always, because we haven’t announced the full slate of talks yet, we’d like to give the Hackaday True Believers out there a bonus: early bird tickets for $150 instead of the regular price of $296 (plus fees). If you know you want to attend (and you know that you want to attend) do not delay and order your tickets now!

As we mentioned before, there are a few exciting changes coming to this year’s Supercon. First off, we are moving to a larger venue on Saturday and Sunday: a few blocks south at the ArtCenter South Campus. We’re looking forward to two larger stages, more room for attendees, and more space to spread out and hack. No longer crammed into a cozy alley, we’ll sprawl out in a luxurious courtyard.

We have more tickets available than ever this year, which is great because Supercons past have all sold out. But we’re not expanding so much that we’ll lose the killer signal-to-noise ratio and friendly hacker atmosphere that makes Supercon our favorite con.

But do get your tickets soon! Whether you get in at the True Believer rate or not, Supercon is a bargain. Two and a half days of fully catered hacking and entertainment, plus the great talks, make it a bargain. Then we throw in sweet hackable badge over the top. But it’s truly the assembled crowd that makes it a priceless experience.

If you’re a Hackaday Supercon regular, we look forward to seeing you again soon! If you’ve always wanted to attend, but never pulled the trigger, the nice round number of Supercon Ten is a great excuse.

Of course, the best way to attend any convention is as a presenter, and our call for proposals just got extended for another two weeks. If you have something you’d like to say: let us know soon!

Holograms, From Your Plotter

When mass-printed holograms appeared on magazines in the 1980s they were a huge novelty, before degrading to the level of kids’ stickers in the years since. At the time they were seen as not for ordinary people to make, but the truth is they can be created without lasers or an optics lab. [Jordan Matelsky] is here to show us how they can be made using as humble a device as a pen plotter.

The effect of an interference pattern from a set of fine lines in a thin film can be demonstrated at its simplest with an oily finger and a mobile phone screen, and once he’s demonstrated that he takes us through some of the theory involved in shifting the light to make an image. There are some false starts with different materials, but eventually he shows us some finished holograms scribed on the polycarbonate of a CD case. It seems you really can make a hologram with a pen plotter. If these images interest you, we’ve looked deeper into the subject in the past. Meanwhile, one of the plotter-scribed holograms can be seen below. Continue reading “Holograms, From Your Plotter”

Bladerunners And The Mother Of Invention

There are plenty of stories about inventors who see a problem and decide they can do better. But Van Phillips had a little more motivation than most. The problem was his own leg. In 1976, Phillips was a 21-year-old college student when a water-skiing accident cost him his left leg below the knee. If that wasn’t bad enough, the prosthetic leg he received afterward wasn’t exactly a technological marvel. Prosthetic limbs of the era were generally designed to look and act something like a biological leg and foot, but “act” might be giving them too much credit. They were passive structures that provided something to stand on and roll over while walking.

Phillips wanted to do more than walk. There was just one problem: he wasn’t an engineer. Before the accident, he had been studying business. So, if he was going to build a better leg, first he was going to have to learn how.

Back To School

Traditional prosthetic feet (public domain)

Phillips became fascinated with prosthetics and eventually studied prosthetic design at Northwestern University’s Prosthetic-Orthotic Center. He also worked at the University of Utah’s prosthetics laboratory, where he had access to both the people and equipment he needed to experiment.

The conventional wisdom was that a prosthetic foot should imitate a human foot. That seems perfectly reasonable — evolution has had quite a long time to work on the design. But there’s a problem with simply copying the shape. A real foot isn’t just a foot-shaped object attached to the bottom of your leg. Muscles, tendons, and ligaments store and release energy as you walk or run. Your Achilles tendon, in particular, acts very much like a spring. A conventional prosthetic foot might look right, but it didn’t have anything corresponding to that spring.

Phillips eventually stopped worrying so much about making something that looked like a foot. Instead, he decided to make something that worked like one.

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Hacking Fiber To The Home

When we think about security threats, we generally imagine them coming from far away across the wider internet. But what if the connection between you and your ISP was the target? [Rithwik Jayasimha] and [Rithvik Vibhu] have explored how fiber to the home connections may not be as secure as you would hope.

The hack centers around fiber-to-the-home connections, of which many deployments rely on Gigabit Passive Optical Network (GPON) standards. The key there is the “passive” part—these networks don’t rely on active components to switch signals. ISPs run central trunk lines out to optical line terminals (OLT), with passive splitters installed in neighborhoods to serve a number of downstream subscribers. Each subscriber then has something called an Optical Network Unit (ONU) in their home, which filters out the traffic intended for that specific subscriber.

Therein lies the flaw, though. Light (and thus, data) for many subscribers flows into the home, and it’s only the ONU that is filtering that out. Hack the ONU, or replace it… and you have access to downstream traffic from your neighbors that you shouldn’t be able to access.

The duo were able to hack an ONU to forward every single frame it receives, revealing downstream data intended for other homes in their immediate neighborhood. A great deal of traffic is encrypted these days, which provides a layer of safety, but it is by no means an ideal situation that such a hack is possible at all. They also explored other threats, such as installing splitters in publicly-accessible infrastructure, and compromising an upstream OLT and using it to flash firmware to other subscriber’s ONUs on the network. All this was presented in a talk at DEF CON, too, which can be viewed online.

It’s a concerning look at an often unconsidered link in the network chain. Few of us expect our data to be snooped upon in between us and the ISP, after all.

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