A Floppy Controller For The Raspberry Pi

March 30, 2021 by 26 Comments

The Raspberry Pi is the darling single board computer that is everything to everyone. It even has lit up the eyes of the older set with the Pi 400 mimicking the all-in-one keyboard computer design so popular in the 1980s. Another project that harkens back to that golden era is this Raspberry Pi floppy controller board from [Dr. Scott M. Baker].

[Scott] is no stranger to floppy controllers, having worked with the popular WD37C65 floppy controller IC before with the RC2014 homebrew Z80 computer. Thus, it was his part of choice when looking to implement a floppy interface on the Raspberry Pi. The job was straightforward, and done with just the IC itself. Despite the Pi running at 3.3 V and the controller at 5 V, [Scott] has found no problems thus far, implementing just a resistor pack to try and limit damage from the controller sending higher voltage signals back to the Pi. With that said, he plans to implement a proper level shifter down the road to ensure trouble-free operation long term.

The project is rounded out with a bunch of Python tools used to interface with the controller, available on Github. Performance is limited by the non-realtime nature of the Raspberry Pi’s user mode operation, which [Scott] notes could be fixed with a kernel module. With that said, if you’re looking for performance, floppies aren’t it anyway.

We do love the Pi put to use in retro tasks; it can even be a SCSI Swiss Army Knife if you need one. Video after the break.

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Raspberry Pi Zero Beams Back Video From 100,000 Feet

March 26, 2021 by 13 Comments

The Project Horus team routinely launches high-altitude balloons in Australia. However, despite their desire for it, they haven’t beamed back live video. Until now. Horus 55 beamed video back to the ground from over 100,000 feet using a Raspberry Pi and some software-defined radio gear. Be sure and check out their video, below.

You might think this is easy, but there are many technical hurdles. First, the transmitter needs some power, but the thin atmosphere creates problems with cooling. In addition a really good receiving station is required, and the project wanted to stream that video to the Internet, which they were able to do.

The balloon carried a Raspberry Pi Zero W to capture and compress video. A LimeSDR Mini provided the DVB-S transmission on 70cm along with a power amplifier to get to about 800mW. Power dissipation in the payload was about 6 watts and required a special heat sink system to operate. The payload was powered by eight lithium AA primary cells, which perform well at low temperatures.

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A Raspberry Pi Tablet, With A DSI Screen

March 24, 2021 by 36 Comments

Since the Raspberry Pi arrived back in 2012, we’ve seen no end of interesting and creative designs for portable versions of the little computer. They often have problems in interfacing with their screens, either on the very cheap models using the expansion port or on more expensive ones using an HDMI screen with associated controller and cabling. The official Raspberry Pi touchscreen has made life easier with its DSI convector, but as [jrberendt] shows us with this neat little tablet, there are other DSI-based options. This one uses a 5″ DSI touchscreen available through Amazon as well as a Pi UPS board to make a tablet that is both diminutive and self-contained.

Having fooled around ourselves in the world of Pi tablets we like this one for its clean look and a bezel that is little bigger than the screen itself. As is the case with so many Pi tablets though it has to contend with the bulk of a full-sized Model B board on its behind, making it more of a chunky brick than a svelte tablet. The screen has potential though, and we can’t help wondering whether there’s any mileage in pairing it with a much thinner Pi Zero board and a LiPo board for a slimmer alternative.

Probably the nicest Pi tablet we’ve brought you was this one, which managed to remain impressively slim despite its HDMI screen.

Raspberry Pi Cosmic Ray Detector

March 16, 2021 by 14 Comments

[Marco] has a sodium iodide detector that indicates cosmic radiation by scintillation. The material glows when hit by cosmic rays and, traditionally, a photomultiplier tube detects the photos from the detection. After a quick demonstration that you can see in the video below, he built the Cosmic Pi, a CERN project to create a giant distributed cosmic ray detector. The Cosmic Pi uses scintillation, but not from a crystal. It uses a plastic scintillator and silicon photodetectors, so it is much easier to work with than a traditional detector.

Using a four-layer board and some harvested components, the device detects muons. There are two scintillation detectors and muons striking both detectors presumably don’t have a local origin. The instrument has a GPS to get accurate time and position data. There are other sensors onboard, too, to collect data about the conditions of each detected event.

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The Raspberry Pi Pico As An SDR Receiver

March 16, 2021 by 30 Comments

With the profusion of cheap RTL-SDR devices and the ever-reducing prices of more capable SDRs there might seem to be little place left for the low-bandwidth devices we’d have been happy with a decade or more ago, but there’s still plenty to be learned from something so simple. It’s something [Luigi Cruz] shows us with a simple SDR using the analogue-to-digital capabilities of the Raspberry Pi Pico, and since it works with GNU Radio we think it’s rather a neat project. CNX Software have the full story, and and quickly reveal that with its 500k samples per second bandwidth it’s not a machine that will set the SDR world on fire even when pushing Nyquist’s Law to the limit.

So with the exception of time signals and a few Long Wave broadcast stations if you live somewhere that still has them, you’ll need a fliter and receive converter to pull in anything of much use radio-wise with this SDR. But a baseband SDR with a couple of hundred kHz useful bandwidth and easy hackability through GNU Radio for the trifling cost of a Raspberry Pi Pico has to be worth a second look. You can see it in action in the video below the break, and if you’re at a loss for what to do with it take a look at Michael Ossmann and Kate Temkin’s 2019 Superconference talk.

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Raspberry Pi Pico ADC Characterized

March 15, 2021 by 21 Comments

[Markomo] didn’t find much useful information about the Raspberry Pi PIco’s analog to digital converter, so he decided to do some tests to characterize it. Lucky for us, he documented the findings and shared them. The results are in a series of blog posts that cover power supply noise, input-referred noise, signal to noise ratio, and distortions.

There are some surprising results. For example, the Pico’s low noise regulator mode appears to produce more noise than having it set for normal operation. There also appears to be a large spike in nonlinearity around certain measurements.

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Raspberry Pi Hitches A Ride In A 1989 BMW Dashboard

March 11, 2021 by 12 Comments

It probably won’t surprise you to find out that a 1989 BMW 325i doesn’t have much in the way of electronic gadgetry onboard. In fact, what passes for an in-dash “computer” in this vintage Beemer is just a digital clock with a rudimentary calendar function. Not content to waste his precious dashboard space any longer, [Ryan Henderson] used his time in quarantine to replace the clock module with a Raspberry Pi.

Nestled in a custom laser-cut housing is a touch screen LCD module that connects directly to the GPIO header of a Pi Zero. Combined with some Python code, this provides a very slick multipurpose interface for pretty much anything [Ryan] wants. Right now he’s got it hooked up to a GPS receiver so he can figure out things like speed and acceleration, but the only real limit on what this little drop-in upgrade can do is how much code you want to sit down and write.

Thankfully, it sounds like [Ryan] has done a lot of the hard work for you. He’s put together a Python library that allows the user to easily draw analog gauges on the screen. The faces are parametrically sized, and even have custom minimum/maximum marks. Of course if you’d rather just throw some text and images on the screen, that’s accomplished easily enough with existing libraries such as PyGame.

[Ryan] says he’s also working on some code to better integrate the Pi into the vehicle’s systems by way of a Bluetooth OBD2 adapter. In the most basic application that would allow you to throw various bits of engine data up on the screen, but on more modern cars, you could potentially tap into the CAN bus and bend it to your will.

While the physical size and shape of this particular modification is clearly focused on this model and year of BMW, the general concepts could be applied to any car on the road. [Ryan] has recently started a GitHub repository for the project and hopes to connect with others who are interested in adding a little modern complexity convenience to their classic rides.

The reality is that cars become more dependent on their onboard computers with each passing year. Already we’re seeing Tesla owners struggle with cooked flash chips, and things are likely to get worse before they get any better. While undoubtedly there are some that would rather keep their daily driver as simplistic as possible, we’re encouraged by projects like this that at least let owners computerize their cars on their own terms.