Meowing Box Will Befuddle Your Friends

January 29, 2022 by Lewin Day 11 Comments

If you don’t own a cat, hearing the sound of one meowing from somewhere in the house probably comes as quite a shock. The Cat Prank box built by [Reuben] promises to deliver such hilarity with aplomb.

The idea is simple: hide the Cat Prank box in a cupboard or other space in a friend’s house, and it will meow from its secret location. When found, either the light sensor or motion sensor will trigger the yowling of an angry feline, with hopefully startling effects.

An Arduino Mini is the brains of the operation, paired with an XY-V17B sound module which plays the required animal wailings. There’s also a 433 MHz radio module that lets the prankster trigger meowing via remote control.

Code is available for those wishing to build their own. We’d love to see a mod with a time delay built in, so the device could be hidden and left to start meowing at some later date when the prankster is far away.

Similar work has graced these pages before, like the devilishly fiendish OpenKobold design. Just make sure your friends are receptive to such jokes before you go ahead and invest time and hardware in the prank!

Recreating MS Paint For The ESP32

January 27, 2022 by Lewin Day 11 Comments

Microsoft Paint was one of the first creative outlets for many children when they first laid hands on a computer in the 1990s. Now, [Volos Projects] has brought the joy of this simple application to a more compact format on the ESP32!

The GUI is a fair bit simpler than even the Windows 3.1 version of MS Paint, looking a little more like something from the very early GUI era. Regardless, one can draw simple shapes in block colors just like the old days, with a pair of potentiometers to move the cursor and twin tactile buttons for selecting tools and committing changes to the canvas.

The build shows that even a 1.3″ 240×240 TFT display can display some charming, colorful graphics, and realistically it’s not far off the resolution most computers had in the late 80s anyway. We’d love to see the software get some more tools too, like the spray can and brushes that were such a key part of the MS Paint experience. Code is available for those eager to play with ES Paint 32 for themselves.

It bears noting that despite some claims to the contrary, MS Paint isn’t dead. Incidentally, if you’re a masochist, you can even program in everybody’s favorite Windows-bundled art program. Video after the break.

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Pocket-Sized Doom Is Actually Playable

January 26, 2022 by Lewin Day 19 Comments

It used to be that you needed a well-equipped expensive new beige-box PC if you wanted to play Doom at all. Now, you can do so in a form factor with a footprint smaller than a credit card, as demonstrated by this nifty little build from Adafruit.

The build relies on the Retro-Go firmware for ESP32 devices, which can emulate a range of machines, from the Nintendo NES and Game Boy to the NEC PC Engine, Atari Lynx, and, yes, Doom itself. It can even run Doom mods, via the WAD architecture used by the game.

It was a simple matter of porting Retro-Go to run on the tiny QT Py ESP32 Pico board, and everything fell into place. With six tactile buttons, it’s capable of not just running Doom, but running it at full playable speeds including that classic soundtrack. The 1.3″ 240×240 screen looks surprisingly crisp and does a great job of displaying the game while keeping everything readable.

It’s one of the smaller Doom-capable portables we’ve seen; we reckon you could stuff this in the change pocket in your jeans if you tried hard enough. We’ll never quite get over seeing the world’s most loved FPS running on commercial kitchen hardware, though. Video after the break.

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Building Switching Points For A Backyard Railway

January 26, 2022 by Lewin Day 7 Comments

A home-built railway is one of the greatest things you could possibly use to shift loads around your farm. [Tim] and [Sandra] of YouTube channel [Way Out West] have just such a setup, but they needed some switching points to help direct carriages from one set of rails to another. Fabrication ensued!

The railway relies on very simple rails made with flat bar and angle iron, allowing the railway to be built without a lot of heavy blacksmithing work. For a light-duty home railway, these are more than strong enough to do the job.

As for the points, a simple V-shaped frog-and-blade design was used. The frog is the V-shaped section where the rails diverge into two directions, sitting in the center of the Y, while the blade is the part that moves to either side to guide the carriages in one way or t’other.

The blade consists of a 2.2 meter long piece of angle iron with a pin welded on, allowing it to pivot. Two pieces of flat bar were then welded together with a pin to make the frog. Two metal bushes were then forced into a wooden sleeper, allowing the blade to pivot as needed. The rails themselves are slightly kinked as needed and everything tacked down into sleepers with bolts and pipe pegs.

The design runs smoothly, much to [Tim]’s enjoyment. It’s a clear improvement over the earlier design we looked at least year.

There’s something inherently charming about a railway built with little more than wood, metal, and hammers. Seeing the little stone wagon run down the rails to bed in the sleepers is utterly joyful in a way that’s difficult to fully explain. Video after the break.
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Display Your Speech In Realtime To Help Lipreaders In The Mask Era

January 23, 2022 by Lewin Day 18 Comments

Masks are all well and good when it comes to reducing the spread of deadly pathogens, but they can make it harder to understand people when they speak. They also make lipreading impossible. [Kevin Lewis] set about building something to help.

The system consists of a small screen that can be worn on the chest or other part of the body, and a lapel microphone to record the wearer’s speech. Using the Deepgram AI speech recognition API running on a Raspberry Pi Zero W, the system decodes the speech and displays it on the Hyperpixel screen.

The API is quite capable, and can be set to only respond to the wearer’s voice, or in a group mode, display speech from multiple people in the area, displaying other voices in another colour. There’s also a translation feature using the iTranslateApp API as well.

It’s a neat tool that could be of great use in conferences or in situations where a quick simple machine translation could majorly ease communication. Video after the break.
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Robot Nerf Alarm Blasts You Awake With Foam

January 21, 2022 by Lewin Day 11 Comments

The sentry gun targets [Vinnie] with blasts of foam as he runs through the bedroom to the sounds of Your New Morning Alarm by [Marc Rebillet].

Waking up is hard; sometimes you need more than a little chiming alarm to get you out of bed. When [Vinnie Satriale] started unconsciously switching his alarms off, he went all out, deciding to build a Nerf sentry blaster to wake him up instead.

A Nerf Rival Nemesis MXVII-10K flywheel blaster is the core of the build, with a 100-round capacity of soft foam balls. Stepper motors are used to control a pan and tilt system to aim the blaster. It’s moved under instruction from a Raspberry Pi that uses machine vision algorithms running on a Coral USB accelerator to track targets in the bedroom. A relay board is then used to activate the blaster’s firing action, blasting any targets until they wake up.

[Vinnie] had plenty of fun during build, also showing the sentry gun off to his coworkers in the office. It’s a hard sentry to dodge, with the machine vision algorithm using a full-body tracking model, so merely covering one’s face won’t be enough to get away.

We’ve seen all kinds of sentry guns over the years, from those firing rubber bands to others spraying jets of water. Video after the break.

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Coin Sorter Is Elegant And Beautiful

January 16, 2022 by Lewin Day 32 Comments

Counting change is a great way to teach children about mathematics and money, but it grows tiresome for those of us that have passed the first grade. Thus, a machine should the job, as [Daniele Tartaglia] demonstrates.

A vibrating motor is used to shake a hopper full of coins, letting them fall through a feeder slot into the machine at a steady rate. They then go through a size-based sorter, which flicks the coins into a different channel depending on their physical dimensions. The coins are counted via infrared sensors wired up to an Arduino, and then pass through a rather lovely maze on their way down to sorting bins at the bottom of the machine.

It’s a tidy build, and a great thing to have if you regularly find yourself needing to count change. We haven’t seen too many coin counters before, but we have seen a laundromat given an overhaul with some hacker skills. Video after the break.

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