Your Cat Needs Its Own TV

March 10, 2024 by Kristina Panos 21 Comments

Cats are wonderful creatures to have around, and they provide us with hours of entertainment. So why not do a little something to entertain them in return? That’s exactly what [Becky Stern] did by making a cat TV that shows YouTube videos of birds and other cat-approved content. Not all cats seem to care about TV, but [Becky]’s cat Benchley really gets into it.

As you may have guessed, this is a fairly simple build, consisting largely of a Raspberry Pi, a speaker, and a screen — a 5″ HDMI LCD display to be exact. Seems like a nice size for cats. After getting the cat-puter up and running, [Becky] set about designing a 3D-printed enclosure to turn it into a TV. The first draft looked great in marble-effect filament, but lacked breathing holes for the Pi, so the final version has a nice honeycomb pattern that is too small for curious cat paws to fit through.

What their paws can do is accidentally pause the video via the touch screen, so [Becky] swapped the USB cable for a charge-only to prevent this. Be sure to check out the build video after the break, because there is plenty of cat cuteness to be had. [Benchley] was so into it that he went looking around back for cats and squirrels inside the box.

Would you rather not encourage your cats to lie about the house watching TV all day? Make them play piano for their dinner.

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The $16 PCB Robot

March 6, 2024 by Al Williams 20 Comments

It is a fun project to build a simple robot but, often, the hardest part these days is creating the mechanical base. [Concrete Dog] has a new open source design for stoRPer that uses a PC board as the base. The board has a Raspberry Pi Pico and motor drivers. The modular design allows you to add to it easily and use custom wheels. The video below shows some treaded wheels and some mechanum wheels with gears.

There are mounting holes for sensors and also a way to put another deck above to hold other circuits, power, or whatever you like. There’s lots you could do with this as a starting point.

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Thumbs Up To This Pico MIDI Kalimba

March 6, 2024 by Kristina Panos 8 Comments

The kalimba, or thumb piano, is an easy way to make some music even if you have next to no idea what you’re doing. The only real downside is that they are limited to the twinkly sounds of metal tines being plucked by thumbs.

[Jeremy Cook] broke the sonic possibilities wide open by converting a couple of kalimbas into capacitive-touch MIDI instruments using the Raspberry Pi Pico. He started with a small one that is curiously made of solid wood. Usually these instruments are at least partially hollow to allow air to resonate inside the body.

After soldering up all the 1 MΩ resistors necessary to utilize the capacitive touch capabilities of the Pico, [Jeremy] found it a bit difficult to play individual notes on such a small instrument, so he made version two out of a much larger specimen.

This time, [Jeremy] cooked up a custom PCB which he is calling the Pico Touch 2, which adds the necessary resistors at the SMD level for capacitive touch sensing and in turn cleans up the wiring a bit. Be sure to check it out in action after the break.

Okay, so you don’t have an iota of musical talent. You could always build a kalimba that plays itself.

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RGB LED Disco Ball Reacts To Sound And Color

March 5, 2024 by Kristina Panos 3 Comments

Although disco music and dancing may be long dead, the disco ball lives on as a staple of dance parties everywhere. [Tim van de Vathorst] spent a considerable amount of time reinventing the disco ball into something covered with RGB LEDs that reacts to sound and uses a color sensor to change hue based on whatever it’s presented with.

[Tim] started by modeling the disco ball after a soccer ball with a mixture of pentagons and hexagons. Then it was off to the laser cutter to cut it out of 3mm plywood sheets. Once assembled, [Tim] added LED strips across all the faces and wired them up. Then it was time to figure out how to hold the guts together inside of the ball. Back to the drawing board and laser cutter [Tim] went to design a simple two-piece skeleton to hold the Raspberry Pi and the power supply.

In order to do some of the really interesting effects, [Tim] had to make sure that the faces were divvied up correctly in code. That was difficult and involved a really big array, but the result looks worth the trouble. Finally, [Tim] covered the ball in white acrylic to diffuse the LEDs. As you will see in the build/demo video after the break, the ball turned out really well. The only real problem is that the camera doesn’t work very well without light, which is something good parties are usually short on. [Tim] might add a spotlight or something in the future.

Do you prefer the mirrored look of the standard disco ball? Peep the tiny one in this Disco Containment Unit.

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The Juggler: In Rust

March 4, 2024 by Dave Rowntree 12 Comments

Back on the theme of learning to program by taking on a meaningful project — we have another raytracing demo — this time using Rust on the Raspberry Pi. [Unfastener] saw our previous article about writing a simple raytracer in spectrum BASIC and got inspired to try something similar. The plan was to recreate the famous juggler 3D demo, from the early days of 3D rendering on the Amiga.

The juggler story starts with an Amiga programmer called [Eric Graham] who created ssg, the first ray tracer application on a personal computer. A demo was shown to Commodore, who didn’t believe it was done on their platform, but a quick follow-up with the actual software used soon quelled their doubts. Once convinced, they purchased the rights to the demo for a couple of thousand dollars (in 1986 money, mind you) to use in promotional materials. [Eric] developed ssg into the popular Sculpt 3D, which became available also on Mac and Windows platforms, and kick-started a whole industry of personal 3D modelling and ray tracing.

Anyway, back to the point. [Unfastener] needed to get up the considerable Rust learning curve, and the best way to do that is to let someone else take care of some of the awkward details of dealing with GUI, and just concentrate on the application. To that end, they use the softbuffer and winit Rust crates that deal with the (important, yet frankly uninteresting) details of building frame buffers and pushing the pixels out to the window manager in a cross-platform way. Vecmath takes care of — you guessed it — the vector math. There’s no point reinventing that wheel either. Whilst [Unfastener] mentions the original Amiga demo took about an hour per frame to render, this implementation runs in real-time. To that end, the code performs a timed pre-render to determine the most acceptable resolution to get an acceptable frame rate, achieving a respectable 30 or so frames per second on a Pi 5, with the older Pis needing to drop the resolution a little. This goes to show how efficient Rust code can be and, how capable the new Pi is. How far we have come.

We saw another interesting rust-based raytracer a while back, which is kinda fun. We’ve also covered rust in other applications a few times, like inside the Linux kernel. Finally here’s our guide to getting started with rust, in case you need any more motivation to have a crack at this upcoming language.

For Today Only, Pi=3

February 29, 2024 by Jenny List 47 Comments

In 1897 the state assembly of the American state of Indiana famously tried and failed to pass a bill which would have had the effect of denying the value of the mathematical constant Pi. It was an attempt to define a method to “square the circle”, or draw a square of the same area as a given circle through a series of compass and straight edge steps. It’s become something of a running joke and internet meme, and of course defining Pi exactly remains as elusive as ever.

Today and today alone though, you can in one sense claim that Pi is 3, because it’s twelve years since the launch of the original Raspberry Pi. The 29th of February 2012 was a leap day, and today being the third leap day since, could be claimed by a date pedant to be the third birthday of the little board from Cambridge. It’s all a bit of fun, but the Pi folks have marked the occasion by featuring an LED birthday cake.

Three leap days ago, your scribe was up at the crack of dawn to be one of the first to snag a board, only to witness the websites of the two distributors at the time, RS and Farnell, immediately go down under the denial of service formed by many thousands of other would-be Pi owners with the same idea. It would be lunchtime before the sites recovered enough to slowly buy a Pi, and it would be May before the computer arrived.

The Pi definitely arrived with a bang, but at tweleve years old is it still smoking? We think so, while it’s normalized the idea of an affordable little board to run Linux to the extent that it’s one of a crowd, the Pi folks have managed to stay relevant and remain the trend setter for their sector rather than Arduino-style becoming an unwilling collective term.

We’ve said this before here at Hackaday, that while the Pi boards are good, it’s not them alone which sets them apart from the clones but their support and software. Perhaps their greatest achievement is that a version of the latest Raspberry Pi OS can still run on that board ordered in February 2012, something unheard of elsewhere in single board computers. If you still have an original Pi don’t forget this, while it’s not the quickest any more there are still plenty of tasks at which they can excel. Meanwhile with their move into branded silicon and their PCIe architecture move we think things are looking exciting, and we look forward to another 12 years and three birthdays for them. Happy 3rd birthday, Raspberry Pi!

DietPi Version 9.1: Now With Raspberry Pi 5 Support And More

February 26, 2024 by Maya Posch 11 Comments

DietPi recently released version 9.1, which among other changes includes new images for the Raspberry Pi 5, Radxa Rock 4 SE and NanoPi R5S/R5C & 6. The Radxa Rock 4 SE image was necessary because the Rock 4’s RK3399 SoC is subtly different from the RK3399-T’s SoC in terms of memory support, which prevents a Rock 4 image from booting on the Rock 4 SE. Meanwhile the Raspberry Pi 5 image is all new and still a bit rough around the edges, with features like the changing of the resolution and camera module support not working yet. These new images are all available for testing.

We covered DietPi previously with their 8.12 release, along with the reasons why you might want to use DietPi over Armbian and Raspberry Pi OS. Essentially DietPi’s main focus is on performance combined with a small installed size, with the included configuration tools and the setup allowing for many more features to be tweaked than you usually find. If the performance improvements, lower RAM usage and faster boot times seen with the Raspberry Pi 4 holds up, then DietPi can just give the Raspberry Pi 5 a nice little boost, while saving power in the process.

Thanks to [StephanStS] for the tip.