Adapter Board Expands The Pi Zero

July 17, 2023 by Bryan Cockfield 23 Comments

The standard Raspberry Pi computers have been in short supply for a while now, so much so that people are going to great lengths to find replacements. Whether it’s migrating to alternative single-board computers or finding clones of the Pi that are “close enough”, there are solutions out there. This method of building a full-size Raspberry Pi with all of the bells and whistles using the much-less-in-demand Pi Zero also stands out as a clever solution.

[SpookyGhost] didn’t build this one himself, but he did stumble across it and write a pretty extensive how-to and performance evaluation for the board, which can be found here. The adapter connects to the Zero’s HDMI and USB ports, and provides all the connectors you’d expect from a larger Pi such as the 3B. It’s not a perfect drop-in replacement though — you don’t get the 3.5 mm audio jack, and the micro SD card location doesn’t match up with where it should be on a “real” Pi.

All things considered, this is one of those solutions that seems obvious in retrospect but we still appreciate its elegance. It might disappear as soon as chip shortages stop being an issue, but for now we’ll take any solutions we can. If you don’t already have a Pi Zero on hand, we’ve seen some other successes replacing them with thin clients or even old smartphones.

Pi Zero Runs DOOM Via Wireless Power

July 15, 2023 by Donald Papp 8 Comments

What’s better than a Raspberry Pi Zero running DOOM on a 3.5″ touchscreen? Running it over wireless power, of course!

[atomic14] has been interested in wireless power for a while, and while most of the hardware he’s tested over the years has been less than impressive, he demonstrates one that’s able to reliably deliver 5 V at about 1 A which is more than enough to boot a Raspberry Pi W2 into X and launch DOOM. But while that’s neat, he explains that wireless power isn’t quite yet an effortless solution.

The hardware can deliver 5 V at about 1 A wirelessly, which is plenty, but coil alignment is critical to efficiency.

For one thing, the hardware he’s using — similar to those used for mobile phone charging — need the receiver to be very close to the transmitter. In addition, they need to be aligned well or efficiency drops off sharply. For mobile phones this isn’t much of a problem, but it’s difficult to position a Raspberry Pi and display just so when one can’t see the coils. Misalignment means brownouts and other unreliable operation.

So while the wireless power is capable of running the Pi directly, [atomic14] attempts to put a small battery and charger circuit into the mix in order to make the whole thing both portable and more reliable. But because nothing is easy, he discovers that his charging board — which should be able to output as low as 4.5 V — isn’t able to be adjusted down any lower than 5.66 V. It turns out that a resistor marked 104 (which should be 100 kΩ) is actually measuring 57 kΩ, and the trim pot doesn’t go lower than 10 kΩ. The solution is a bit of component swapping, but we suppose it’s a reminder that sometimes with cheap parts, one pays in other ways.

You can see [atomic14]’s wireless power Raspberry Pi running the classic shooter in the video below. Wireless power may have its issues, but it’s certainly a lot less messy than running DOOM with a gigantic potato battery.

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Listening To Bats As They Search For Food

July 14, 2023 by Bryan Cockfield 14 Comments

The range of human hearing goes up to about 20 kilohertz, which is fine for our purposes, but is pretty poor compared to plenty of other animal species. Dogs famously can hear up to about 60 kHz, and dolphins are known to distinguish sounds up to 100 kHz. But for extremely high frequencies we’ll want to take a step into the world of bats. Some use echolocation to locate each other and their food sources, and bats like the pipistrelle can listen in to sounds up to 350 kHz. To listen to them you’ll need a device like the π*pistrelle. (Ed Note: a better explanation is available at the project’s website.)

The original implementation of the bat detector was based on a Raspberry Pi Pico, from which it gets its name. But there have been several improvements on it in the years since it was first developed. The latest can detect bats when it hears their 350 kHz sonar calls thanks to an ultrasonic microphone and op amp. The device then records the bat sounds and then either heterodynes the sound down or time-expands it to human-audible range so the calls can actually be heard. There’s an LED display on the board as well as three input buttons, but an iOS companion app is available to interact with the device as well.

If you want to know for sure which species is flying around at night, you can use machine learning to help figure that out.

Raspberry Pi Pico W Now Supports Bluetooth

June 15, 2023 by Tom Nardi 11 Comments

What’s the best kind of upgrade a piece of consumer technology can get? A free one that doesn’t require you to do anything other than accept a new version of the software it’s running.

That’s precisely what every current (and future) owner of the Raspberry Pi Pico W just got with the addition of Bluetooth support to SDK 1.5.1. This is possible because the CYW43439 radio chipset used on the wireless version of the Pi Pico has always had Bluetooth capabilities, they just weren’t officially accessible from the C or MicroPython environments until now. In a corresponding blog post, [Eben Upton] explains that part of the delay was due to difficulties in getting both WiFi and Bluetooth connections to work simultaneously over the three-pin SPI bus that links the two chips on the board.

One thing that struck us as particularly interesting here is the use of BlueKitchen’s BTStack to provide support for both Bluetooth Classic and Low Energy profiles. This library is released under a modified version of the BSD 3-Clause license that otherwise specifically forbids commercial usage. That would be a problem for anyone who wanted to sell a gadget built around the Pico W, so Raspberry Pi Ltd negotiated — and presumably paid for — a special dispensation so commercial use is in the clear.

We should note that technically Bluetooth support was available in a beta state previously, albeit without this new license agreement made with BlueKitchen. Though anyone with a keen eye knew Bluetooth support was coming well before that, our own [Elliot Williams] called it when he first set eyes on the Pi Pico W back in 2022.

Zelda Guardian Sculpture Tracks Humans And Pets Via Camera

June 3, 2023 by Lewin Day 3 Comments

In The Legend of Zelda: Breath of the Wild Guardians are a primitive form of sentry turret that tracks the player with a watchful eye. Inspired by this, [npentrel] decided to whip up one of her own in the real world.

The build relies on a Raspberry Pi kitted out with its usual camera for machine vision purposes. It uses the Viam robot toolkit, which runs a machine learning model to detect pets and humans on the camera feed. The guardian then tracks any pets or humans that show up by turning its head, and thus the camera, with a servo controlled by a PWM signal via the Raspberry Pi’s GPIO pins. It’s all wrapped up in a nicely-decorated 3D printed model that really does look like something straight out of Breath of the Wild.

Sentry projects are a great way to learn about electronics, mechanics, and image processing techniques. It’s funny to see how advanced and complicated these projects were fifteen years ago, compared to how easy they are today with modern machine learning libraries. How times change!

What Next For The SBC That Has Everything?

May 31, 2023 by Jenny List 113 Comments

In the decade-and-a-bit since the first Raspberry Pi was launched we’ve seen an explosion of affordable single-board computers (SBCs), but as the prices creep up alongside user expectation and bloat, [Christopher Barnatt] asks where the industry will go next.

The Pi started with an unbeatable offer, $35 got you something similar to the desktop PC you’d had a decade earlier — able to run a Linux desktop on your TV from an SD card. Over the years the boards have become faster and more numerous, but the prices for ARM boards are now only nominally as affordable as they were in 2012, and meanwhile the lower end of x86 computing is now firmly in the same space. He demonstrates how much slower the 2023 Raspberry Pi OS distribution is on an original Pi compared to one of the early pre-Raspbian distros, and identifies in that a gap forming between users. From that he sees those people wanting a desktop heading towards the x86 machines, and the bare-metal makers at the lower end heading for the more powerful microcontrollers which simply weren’t so available a decade ago.

We have to admit that we agree with him, as the days when a new Raspberry Pi board was a special step forward rather than just another fast SBC are now probably behind us. In that we think the Pi people are probably also looking beyond their flagship product, as the hugely successful lunches of the RP2040 and the industrial-focused Compute Module 4 have shown.

What do you think about the SBC market? Tell us in the comments.

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Mangle Videos With RecurBOY And A Raspberry Pi Zero

May 28, 2023 by Elliot Williams 6 Comments

You used to need a lot of equipment to be a video DJ. Now you can do it all with a Raspberry Pi Zero and [cyberboy666]’s recurBOY. And if you missed out on the 1970’s video-editing psychedelia, now’s your chance to catch up – recurBOY is a modern video synth with all of the bells and whistles, and it’ll fit in your pocket. Check out [cyberboy666]’s demo video if you don’t yet know what you’re getting into. (Embedded below.)

RecurBOY has four modes: video, shader, effects, and external input, and each of these is significantly cooler than the previous. Video mode plays videos straight off of the SD card through the recurBOY’s composite video out. Shader mode lets you program your own shaders using the GLES shader dialect for resource-constrained devices. And this is where the various knobs and buttons come in. You can program the various shader routines to read any of the pots as input, allowing you to tweak the graphics demos on the fly.

Effects mode overlays your shaders on the video that’s playing, and external mode allows you to plug in a USB video capture card or a webcam so you can do all that same mangling with a live camera feed. And these two modes are where it gets awesome. The shader effects in the demo video cover all of the analog classics – including bloom and RGB separation – but also some distinctly digital effects. And again, you can tweak them all live with the knobs. Or plug in a MIDI controller and control it all externally. What hasn’t he thought of?

Old school analog video effects are really fun, and recurBOY brings them to you with the flexibility of modern shader coding. What’s not to love? If you want to see the pinnacle of the pre-digital era, that would be the Scanimate. For a video synth that integrates with your audio synth, check out Hypno. And if glitching the video is more your style, you can hijack the RAM of a VGA/composite converter.

Trippy, man!

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