Interactive Cake Takes Your Picture

[Abigail] is a confectionery roboticist, and [Hazal] is a developer advocate at a robotics company. The two met recently and decided to collaborate on a smart cake, with amusing results.

The resulting cake not only looks like a camera it also has a camera inside. When the camera detects people in its field of view, a NeoPixel is lit up in green to signal it’s spotted something. If you so desire, you can then hit a button and the cakera (cake-camera, keep up) will take your photo.

The cake itself looks to be a sponge of some sort with fondant used to create the camera housing and a surround for the preview screen. Inside the cake is a standard photo-booth style setup built with a Raspberry Pi. The Pi is responsible for taking photos with a USB cam. It does this when instructed via an arcade button acting as the shutter release. After taking a photo, the Pi prints out a receipt with an Adafruit thermal printer. This provides the user a number they can use to receive their photo afterward.

We’ve seen some neat cakes before, too. If you’ve been hacking on cakes, either edible or theoretical, we might just want to know more. Drop us a line!

Left: a DIY chording keyboard with seven keys Right: the guts of said keyboard

Chording Keyboard Leaves Your Mouse Hand Free

[akmnos22] was getting tired of moving one hand to the mouse and back to the keyboard. Rather than integrating mouse controls into a keyboard, they decided to really lean in and create a chording keyboard — one that creates characters with combinations of key presses, like playing chords on a piano.

This project was inspired in part by the Infogrip BAT, which has graced these pages before. Much like the BAT, this uses a total of seven Cherry MX switches: one for each finger, and three for the thumb. In order to get the placement just right for you, [akmnos22] suggests laying your hand in a comfortable position on a piece of paper and marking where your fingers naturally rest, then importing these markings into CAD software to decide where the key switch holes should be.

The brains of this operation is a Raspberry Pi Pico, which provides more than enough GPIO pins to do the job. [akmnos22] does a nice job of explaining exactly how to put one of these together, from the design concept through the programming process and how to actually chord on the thing.

Would you rather chord with two hands? It might be even faster.

RP2040 Boot Loader Is A Worm

[Hunter Adams] has written a secondary bootloader for the RP2040 that uses an IR link and can be extended to behave like a polite worm virus. This allows the easy updating of a large cluster of co-located RP2040-based controllers. This could be handy in applications like swarm robotics or virtual cattle fencing. The project he demonstrates in the two videos ( below the break ) uses a pair of IR transmitters/receivers. But he purposely wrote the boot loader to be independent of the serial link, which could be infrared, radio, audio, or just wires.

Not only did [Hunter] make a boot loader, but he documented the entire boot process of the RP2040 chip. Whether or not you need a secondary bootloader, this is an excellent resource for understanding how the RP2040 responds to power cycling and resets. The boot loader code is available at his GitHub repository.

You may recall that [Hunter] is the lecturer of Cornell University’s Designing with Microcontroller classes, whom we’ve mentioned before. We’ve also covered some of his students’ projects as well, like these air drums and this CoreXY pen plotter.

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PDP-10 Fits In Your Living Room

[Oscar] at Obsolescence Guaranteed is well-known for fun replicas of the PDP-8 and PDP-11 using the Raspberry Pi (along with some other simulated vintage computers). His latest attempt is the PDP-10, and you can see how it looks in the demo video below.

Watching the video will remind you of every old movie or TV show you’ve ever seen with a computer, complete with typing noise. The PDP-10, also known as a DECsystem-10, was a mainframe computer that usually ran TOPS-10. These were technically “mainframes” in 1966, although the VAX eclipsed the system. By 1983 (the end of the PDP-10’s run), around 1,500 had been sold, including ones that ran at Harvard, Stanford, Carnegie Mellon, and — of course — MIT. They also found homes at CompuServe and Tymshare.

The original 36-bit machine used transistors and was relatively slow. By the 1970s, newer variants used ICs or ECL and gained some speed. A cheap version using the AM2901 bit-slice CPU and a familiar 8080 controlling the system showed up in 1978 and billed itself as “the world’s lowest cost mainframe.”

The Knight terminals were very unusual for the day. They each used a PDP-11 and had impressive graphics capability compared to similar devices from the early 1970s. You can see some of that in the demo video.

Naturally, anyone who used a PDP-10 would think a Raspberry Pi was a supercomputer, and they wouldn’t be wrong. Still, these machines were the launching pad for Adventure, Zork, and Altair Basic, which spawned Microsoft.

The cheap version of these used bitslice which we’ve been talking about lately. [Oscar] is also known for the KIMUno, which we converted into a COSMAC Elf.

PCB Design Review: DPI-LVDS Sony Vaio LCD Devboard

Ordering a PCB with mistakes sucks. We should help each other avoid such mistakes – especially newcomers. One of the best ways to avoid these mistakes, especially if it’s your first one, is to get a few other people to look at it. You deserve to get a PCB that is as functional and as helpful as humanly possible, so that you can be happy with your project, and feel ever so slightly more confident in yourself in whatever you shall set out to do next.

At the end of last year, I put out a call for design review submissions, and we’ve received enough projects to make me feel overwhelmed for a bit. A design review has always felt like a personal thing, and here we are doing them in public. But in that sense, we hope that everyone can learn from them, and we hope to push forward a healthy review culture.

What’s more, these articles won’t just be design review. Every project I’m highlighting is worthy of a Hackaday feature just on its own, so tune in and learn more about them!

Today’s Contestant

For this example, I will be walking through a review I’ve already given someone with a pretty cool board, for a pretty cool project I’ve already shown you. Remember the Sony Vaio remake project? A fair bit of people have reached out to me afterwards, and one of them, [Exentio] also had the same Sony Vaio rebuild idea in mind. We started chatting, and he decided to tackle one of the project’s milestones, and perhaps the most crucial one – adapting the LCD.

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Your Cat Needs Its Own TV

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

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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