raspberry pi

1624 Articles

Raspberry Pi Simulates The Real Analog TV Experience

June 20, 2022 by 18 Comments

If you’ve laid hands on a retro analog TV, have the restoration bug, and you plan to make the final project at least somewhat period-correct, you face a bit of a conundrum: what are you going to watch? Sure, you can serve up just about any content digitally these days, but some programs just don’t feel right on an old TV. And even if you do get suitably retro programming, streaming isn’t quite the same as the experience of tuning your way through the somewhat meager selections as we did back in the analog days.

But don’t worry — this Raspberry Pi TV simulator can make your streaming experience just like the analog TV experience of yore. It comes to us from [Rodrigo], who found a slightly abused 5″ black-and-white portable TV that was just right for the modification. The battery compartment underneath the set made the perfect place to mount a Pi, which takes care of streaming a variety of old movies and shorts. The position of the original tuning potentiometer is read by an Arduino, which tells the Pi which “channel” you’re currently tuned to.

Composite video is fed from the Pi’s output right into the TV’s video input, and the image quality is just about what you’d expect. But for our money, the thing that really sells this is the use of a relay to switch the TV’s tuner back into the circuit for a short bit between channel changes. This gives a realistic burst of static and snow, just like we endured in the old days. Hats off to [Rodrigo] for capturing everything that was awful about TV back in the day — Mesa of Lost Women, indeed! — but still managing to make it look good.

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Turing Pi 2: The Low Power Cluster

June 16, 2022 by 39 Comments

We’re not in the habit of recommending Kickstarter projects here at Hackaday, but when prototype hardware shows up on our desk, we just can’t help but play with it and write it up for the readers. And that is exactly where we find ourselves with the Turing Pi 2. You may be familiar with the original Turing Pi, the carrier board that runs seven Raspberry Pi Compute boards at once. That one supports the Compute versions 1 and 3, but a new design was clearly needed for the Compute Module 4. Not content with just supporting the CM4, the developers at Turing Machines have designed a 4-slot carrier board based on the NVIDIA Jetson pinout. The entire line of Jetson devices are supported, and a simple adapter makes the CM4 work. There’s even a brand new module planned around the RK3588, which should be quite impressive.

One of the design decisions of the TP2 is to use the mini-ITX form-factor and 24-pin ATX power connection, giving us the option to install the TP2 in a small computer case. There’s even a custom rack-mountable case being planned by the folks over at My Electronics. So if you want 4 or 8 Raspberry Pis in a rack mount, this one’s for you.
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At Last! A Cyberdeck You Might Want To Use

May 31, 2022 by 14 Comments

Cyberdecks make for interesting projects, some are a bit rough while others are beautiful, but it’s maybe something that even the most ardent enthusiast might agree — these home-made portable computers aren’t always the most convenient to use. Thus we’re very pleased to see this machine from [TRL], as it takes the cyberdeck aesthetic and renders it in a form that looks as though it might be quite practical to use.

It takes a Raspberry Pi and a Waveshare 1280×400 capacitive touch screen, and mounts this combo with a keyboard in an uncommonly well-designed 3D printed chassis.  With the screen flat it resembles the venerable TRS-80 Model 100 “slab” computer of the early 1980s, but flip it up, and a surprisingly usable laptop appears. Power comes from an external battery pack with a lead, but this is due more to thermal management issues with PSU boards than it is to necessity. The finishing touch is a stylish custom laptop bag, making for a combo we’d take on the train to bang out Hackaday articles any day.

Looking around, we think perhaps it might give the Clockwork DevTerm a run for its money. Alternatively, you might take a look at this upgraded TRS-80 model 100.

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A Raspberry Pi As An Offboard Display Adapter

May 9, 2022 by 6 Comments

The humble USB-C port has brought us so many advantages over its USB ancestors, one of which is as a handy display output for laptops. Simply add an inexpensive adapter and you can hook up everything from a mobile phone upwards to an HDMI display or projector. There’s a snag though, merely having USB-C is not enough as the device has to support the display feature. It’s a problem [Gunnar Wolf] had to face with a Lenovo ARM laptop, and his solution is unexpected. Instead of an adapter, he’s used a Raspberry Pi 3 and some software tricks.

The obvious route to an off-board Pi mirroring onboard video is to use VNC, which he tried but found wanting due to lagginess. As a user of the Wayland compositor he found he could instead use wf-recorder and send its output to a stream, and thus capture his screen in a way that the Pi could read over the network. It’s not quite as convenient a solution as a pure-hardware adapter, but at least it allowed him to share the screen.

It’s surprising how often we find projects needing to mirror the display of a computer using what hardware is to hand, at least this one is more elegant than some others.

Learn Sign Language Using Machine Vision

April 30, 2022 by 9 Comments

Learning a new language is a great way to exercise the mind and learn about different cultures, and it’s great to have a native speaker around to improve the learning experience. Without one it’s still possible to learn via videos, books, and software though. The task does get much more complicated when trying to learn a language that isn’t spoken, though, like American Sign Language. This project allows users to learn the ASL alphabet with the help of computer vision and some machine learning algorithms.

The build uses a computer vision model in MobileNetV2 which is trained for each sign in the ASL alphabet. A sign is shown to the user on a screen, and the user needs to demonstrate the sign to the computer in order to progress. To do this, OpenCV running on a Raspberry Pi with a PiCamera is used to analyze the frames of the user in real-time. The user is shown pictures of the correct sign, and is rewarded when the correct sign is made.

While this only works for alphabet signs in ASL currently, the team at the University of Glasgow that built this project is planning on expanding it to include other signs as well. We have seen other machines built to teach ASL in the past, like this one which relies on a specialized glove rather than computer vision.

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This Machine-Vision Ekranoplan Might Just Follow You Home

April 29, 2022 by 9 Comments

What is it that’s not quite either a plane or a boat, but has characteristics of both? There are probably a lot of things that fit that description, but the one that [Nick Rehm] is working on is known as an ekranoplan. Specifically, he’s looking to make the surface-skimming ground-effect vehicle operate autonomously.

If you think you’ve heard about ekranoplans around here before, you’d be right — we’ve covered a cool LIDAR-controlled model ekranoplan that [rctestflight] worked on about a year ago, and more recently, [ThinkFlight]’s attempts to make an autonomous ekranoplan that can follow behind a boat. The latter is where [Nick] enters the collaboration, and the featherweight foam ground-effect vehicle shown in the video below is his test platform.

After sorting out the basic airframe design and getting the LIDAR integrated, he turned his attention to the autonomous bit, which relies on a Raspberry Pi 4 running ROS and a camera with a wide-angle lens. The Pi uses machine vision algorithms to find an “AprilTag” fiducial marker in the scene, which gives the flight controller information about the relative orientation of the ekranoplan to the tag. [Nick] tested tag tracking using an electric longboard, and the model ekranoplan did an admirable job of not only managing the ground-effect, but also staying on target right behind him. And hats off to [Nick] for keeping all the balls in the air and not breaking his neck in the process.

We’re looking forward to seeing what [Nick] built here end up in [ThinkFlight]’s big ekranoplan build. Ground-effect vehicles like these are undeniably cool, and it seems like they’ve got the potential to solve some interesting transportation problems.

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A Real GPU On The Raspberry Pi — Barely.

April 28, 2022 by 36 Comments

[Jeff Geerling] saw the Raspberry Pi Compute Module 4 and its exposed PCI-Express 1x connection, and just naturally wondered whether he could plug a GPU into that slot and get it to work. It didn’t. There were a few reasons why, such as the limited Base Address Register space, and drivers that just weren’t written for ARM hardware. A bit of help from the Raspberry Pi software engineers and other Linux kernel hackers and those issues were fixed, albeit with a big hurdle in the CPU. The Broadcom chip in the Pi 4, the BCM2711, has a broken PCIe implementation.

There has finally been a breakthrough — Thanks to the dedicated community that has sprung up around this topic, a set of kernel patches manage to work around the hardware issues. It’s now possible to run a Radeon HD 5000/6000/7000 card on the Raspberry Pi 4 Compute Module. There are still glitches, and the Kernel patches to make this work will likely never land upstream. That said, It’s possible to run a desktop environment on the Radeon GPU on a Pi, and even a few simple benchmarks. The results… aren’t particularly inspiring, but that wasn’t really ever the point. You may be asking what real-world use is for a full-size GPU on the Pi. Sure, maybe crypto-mining or emulation, or being able to run more monitors for digital signage. More than that, it might help ensure the next Pi has a working PCIe implementation. But like many things we cover here, the real reason is that it’s a challenge that a group of enthusiasts couldn’t leave alone.

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