Robot Air Hockey Player Predicts Your Next Move

Air hockey is a fun game, but it’s one you can’t play by yourself. That is, unless you have a smart robot hockey player to act as your rival. [Zeroshot] built exactly that.

The build is based around a small 27-inch air hockey table—not exactly arcade-spec, but big enough to demonstrate the concepts at play. The robot player moves its mallet in the X and Y axes using a pair of NEMA17 stepper motors and an H-belt configuration. To analyze the game state, there’s a Raspberry Pi 3B fitted with a camera, and it has a top-down view of the board. The Pi gives the stepper motors commands on how to move the mallet via an Arduino that communicates with the stepper drivers.  The Pi doesn’t just aim for the puck itself, either. With Python and OpenCV, it tries to predict your own moves by tracking your mallet, and the puck, too. It predicts the very-predictable path of the puck, and moves itself to the right position for effective defence.

Believe it or not, we’ve featured quite a few projects in this vein before. They’ve all got their similarities, and their own unique quirks. Video after the break.
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Emulating The Battery Controller In An Ancient Acer PDA

[Mark B] had a problem. He’d come into possession of an Acer N30 PDA, sans batteries. He couldn’t just throw any old cells in, since the unit expected to communicate with an onboard controller chip in the original pack. What ensued was his effort to emulate the original battery controller hardware. This is classic Hackaday right here, folks.

Just wiring in typical Li-Ion voltages to the PDAs battery pins wasn’t enough to make this Windows CE device happy. The device kept fleeing to sleep mode, thinking the battery was faulty or very low. Eventually, inspecting the motherboard revealed the PDA hosted a BQ24025 charger IC from Texas Instruments. [Mark] surmised it was trying to communciate with a BQ26500 “gas gauge” IC from the original battery pack. Armed with that knowledge, he then set about programming an STM32 chip to emulate its behavior. He then successfully ported the functionality over to a CH32V003 microcontroller as well. Paired with a Nokia BL-5CT battery, he had a working portable power solution for his PDA.

It’s great to see ancient hardware brought back to functionality with some good old fashioned hacking. I’d hoped to do the same with my Apple Newton before someone nicked it from my lounge room, more’s the pity. If you’re rescuing your own beleaguered battery-powered portables, don’t hesitate to let us know!

Using A Smartphone As A Touchscreen For Arduino

If you want a good display and interface device for an embedded project, it’s hard to look past an old smartphone. After all, you’ve got an excellent quality screen and capacitive touch interface all in the same package! [Doctor Volt] explains how to easily set up your old smartphone to work as a touchscreen for your Arduino.

[Doctor Volt] demonstrates the idea with a 2018 Samsung Galaxy A8, though a wide variety of Android phones can be put to use in this way. The phone is connected to the Arduino via a USB-to-serial converter and an OTG cable. Using a USB-C phone with Power Delivery is ideal here, as it allows the phone to be powered while also communicating with the Arduino over USB.

The RemoteXY app is built specifically for this purpose. It can be installed on an Android phone to allow it to communicate effectively with Arduino devices, which run the RemoteXY library in turn. Configuring the app is relatively straightforward, with a point-and-click wizard helping you designate what hardware you’re using and how you’ve got it hooked up. [Doctor Volt] does a great job of explaining how to hook everything up, and how to build some simple graphical interfaces.

There are a ton of display and interface options in the embedded space these days, many of which can be had cheaply off the shelf. Still, few compete with the resolution and quality of even older smartphones. It’s a neat project that could come in very handy for your next embedded build! Video after the break.

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3D-Printed Boat Feeds The Fishes

In most natural environments, fish are able to feed themselves. However, if you wanted to help them out with some extra food, you could always build a 3D-printed boat to do the job for you, as [gokux] did.

The concept is simple enough—it’s a small radio-controlled boat that gets around the water with the aid of two paddle wheels. Driven together, the paddle wheels provide thrust, and driven in opposite directions, they provide steering. A SeeedStudio XIAO ESP32 is the brains of the operation. It listens into commands from the controller and runs the paddle drive motors with the aid of a DRV8833 motor driver module. The custom radio controller is it itself running on another ESP32, and [gokux] built it with a nice industrial style joystick which looks very satisfying to use. The two ESP32s use their onboard wireless hardware to communicate, which keeps things nicely integrated. The boat is able to putter around on the water’s surface, while using a servo-driven to deliver small doses of food when desired.

It’s a neat build, and shows just what you can whip up when you put your 3D printer to good use. If you’d like to build a bigger plastic watercraft, though, you can do that too. Video after the break.

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A Red Ring Light Show For Your Xbox 360

The Red Ring of Death (RROD) was the bane of many an Xbox 360 owner. The problem was eventually solved, mostly, but memories of that hellish era lurk in the back of many a gamer’s mind. For a more cheery use of those same status lights, you might appreciate “Lightshow” from [Derf].

The concept is simple enough. It’s a small application that runs on an Xbox 360, and allows you to test the individual LEDs that make up the Ring of Light indicator, along with the main power LED. If you want to test the lights and see each segment correctly lights up as green, yellow and red, you can.

Alternatively, you can have some fun with it. [Derf] also programmed it to flash along to simple four-channel MIDI songs. Naturally, Sandstorm was the perfect song to test it with. It may have been the result of a simple throwaway joke, but [Derf] delivered in amusing fashion nonetheless.

Lightshow is an entry for Xbox Scene Modfest 2024; it’s nice to see the community is still popping off even in this era of heavily-locked-down consoles. We’ve featured some other useful 360 hacks in recent months, too. Video after the break.

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It’s Critical: Don’t Pile Up Your Fissionable Material

Nuclear fission is a powerful phenomenon. When the conditions are right, atomic nuclei split, releasing neutrons that then split other nuclei in an ongoing chain reaction that releases enormous amounts of energy. This is how nuclear weapons work. In a more stable and controlled fashion, it’s how our nuclear reactors work too.

However, these chain reactions can also happen accidentally—with terrifying results. Though rare, criticality incidents – events where an accidental self-sustaining nuclear chain reaction occurs – serve as sobering reminders of the immense and unwieldy forces we attempt to harness when playing with nuclear materials.

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Creating A Radiation King Radio In The Real World

If you’re a fan of the Fallout series of games, you’ve probably come across a Radiation King radio before. In the game, that is, they don’t exist in real life. Which is precisely why [zapwizard] built one!

Externally, the design faithfully recreates the mid-century design of the Radiation King. It’s got the louvered venting on the front panel, the chunky knobs, and a lovely analog needle dial, too. Inside, it’s got a Raspberry Pi Zero which is charged with running the show and dealing with audio playback. It’s paired with a Pi Pico, which handles other interface tasks.

It might seem simple, but the details are what really make this thing shine. It doesn’t just play music, it runs a series of simulated radio stations which you can “tune into” using the radio dial. [zapwizard dives into how it all works—from the air core motor behind the simulated tuning dial, to the mixing of music and simulated static. It’s really worth digging into if you like building retro-styled equipment that feels more like the real thing.

It’s not just a prop—it’s a fully-functional item from the Fallout universe, made manifest. You know how much we love those. If you’re cooking up your own post-apocalyptic hacks, fictional or non-fictional, don’t hesitate to let us know.