A Nerf Gun Upgrade

February 18, 2021 by Bryan Cockfield 16 Comments

A lot of us have nostalgia for our childhood toys, and as long as they’re not something like lawn darts that nostalgia often leads to fun upgrades since some of us are adults with industrial-sized air compressors. Classics like Super Soakers and Nerf guns are especially popular targets for improvements, and this Nerf machine gun from [Emiel] is no exception.

The build takes a Nerf ball-firing toy weapon and basically tosses it all out of the window in favor of a custom Nerf ball launching rifle. He starts with the lower receiver and machines a pneumatic mechanism that both loads a ball into the chamber and then launches it. This allows the rifle to be used in both single-shot mode and also in fully-automatic mode. From there, a barrel is fashioned along with the stock and other finishing touches.

[Emiel] also uses a high-speed camera to determine the speed of his new Nerf gun but unfortunately it isn’t high-speed enough, suffering from the same fate as one of the fastest man-made objects ever made, and he only has a lower bound on the speed at 400 km/h. If you don’t want to go fast with your Nerf builds, though, perhaps you should build something enormous instead. Continue reading “A Nerf Gun Upgrade” →

Racing Game Crashes Into Its Next Life As A Sound Bender

February 15, 2021 by Kristina Panos 1 Comment

They say the best things in life are free, but we would loudly argue that a dollar can go a long way, too. It all depends on what you do with it. When [lonesoulsurfer] saw this busted-up handheld racing game at the junk store, he fell in love with the lines of the case and gladly forked over a buck in order to give it a new life as a wicked little sound-bending machine with dancing LEDs.

Here’s how it works: [lonesoulsurfer] records a few seconds of whatever into the mic with the looping function switched off, then turns it back on to start the fun. He can vary the pitch with the speed controller pot, or add in some echo and reverb. Once the sound is dialed in, he works the pause button on the left to make melodies by stopping and restarting the loop, or just pausing it momentarily depending on the switch setting.

The electronics are a mashup of modules mixed with a custom PCB that combines the recording module with an LM386 amplifier and holds the coolest part of this build — those LEDs that dance to the music behind the toy’s original lenticular screen. Like most of [lonesoulsurfer]’s builds, it’s powered by an old cell phone battery that’s buck-boosted to 5 V. Check out the build and bleep-bloop video after the break.

Lenticular lenses are all kinds of fun. Get one that’s big enough, and you can use it to disappear for a while.

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Driving Upside Down With An RC Fan Car

February 3, 2021 by Lewin Day 8 Comments

We’ve all seen those tiny little RC cars that can climb walls thanks to the suction generated with fans. Their principle is essentially the opposite to that of a hovercraft. [Engineering After Hours] wanted to build his own RC car that could do the same, driving upside down and generating huge amounts of grip.

The build is based on a Traxxas RC car, but heavily modified for the task. An undertray is crafted, with ducts feeding a pair of twin 50mm electric fans. A skirt is fitted around the edge of the undertray, helping create a seal to maximise the downforce generated. This skirt is the area of much engineering effort, as it must form a good seal with the ground, particularly over minor pertubations, without creating undue levels of friction. Suspension components correspondingly need to be beefed up to stop the car bottoming out with the huge downforce generated by the fan system.

After much experimentation, the kinks are worked out, and the car is able to drive upside down successfully. It generates far more downforce than earlier wing experiments from [Engineering After Hours], as expected – with a tradeoff of higher weight and complexity. With the plan to create an RC car capable of huge lateral acceleration, we can’t wait to see what comes next. Video after the break.

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Youngster’s ESP32 Jukebox Uses RFID To Queue Tunes

February 2, 2021 by Tom Nardi 14 Comments

Though kids today have an incredible knack for figuring out modern phones and tablets, there’s still something to be said for offering a simple physical user interface for little hands. To that end, [Martin Hierholzer] has put together a whimsical jukebox that his two year old daughter can use to listen to her favorite songs. With just a few simple buttons, no display to read, and the ability to stop and start songs using RFID tags embedded into 3D printed figures, it’s a perfect interface for tiny humans just getting the hang of interacting with technology.

While the Raspberry Pi might have been the more obvious choice to base this project around, [Martin] decided to go the ESP32 route for improved energy efficiency. The popular microcontroller is more than powerful enough to play MP3s, and its integrated WiFi connectivity allows the player to download new tracks from the network occasionally. He added a micro SD slot to provide some mass storage, a PCM5102 I2S DAC with a PAM8403 amplifier to handle the audio side of things, and a MFRC522 RFID receiver that can pick up tags placed on the top of the player. Power is provided by parts salvaged from a USB battery bank, and everything is housed on a custom PCB.

The relatively low power requirements of the ESP32 means the jukebox can keep the party going for many hours (perhaps even days) when in active use. When the RFID token is removed and there are no songs to play, some clever coding kicks the chip into low-power mode to greatly extend the player’s standby time. [Martin] says it can sleep for months without having to be recharged, and considering some of the impressive feats of battery-sipping we’ve previously seen from the ESP32, we don’t doubt it.

Even if you don’t have any young music lovers at home, the documentation [Martin] has put together for this project is absolutely worth a look. Whether its how he configures the server side to push songs and firmware updates to the player, how he wrangled the ESP32’s Ultra-Low Power coprocessor (ULP), or the woodworking tips used to produce the charming enclosure, you’re sure to pick up a trick or two.

The children of hackers and makers always seem to get the coolest stuff, and we’re looking forward to seeing what [Martin] comes up with next. After all, kids grow up fast and pretty soon his daughter is going to need something new to entertain her.

Building A 60s Toy The Way It Should Have Been

February 2, 2021 by Dan Maloney 24 Comments

The original Hasbro “Think-a-Tron”, a toy from the dawn of the computer revolution, was billed with the slogan, “It thinks! It answers! It remembers!” It, of course, did only one of these things, but that didn’t stop the marketers of the day from crushing the hopes and dreams of budding computer scientists and their eager parents just to make a few bucks. It’s not like we’re bitter or anything — just saying.

In an effort to right past wrongs, [Michael Gardi] rebuilt the 1960s “thinking machine” toy with modern components. The original may not have lived up to the hype, but at least did a decent job of evoking the room-filling computers of the day is a plastic cabinet with a dot-matrix-like display. The toy uses “punch-cards” with printed trivia questions that are inserted into the machine to be answered. A disk with punched holes spins between a light bulb and the display lenses, while a clever linkage mechanism reads the position of a notch in the edge of the card and stops the wheel to display the letter of the correct answer.

[Michael]’s update to the Think-aTron incorporates what would have qualified as extraterrestrial technology had it appeared in the 1960s. A 35-LED matrix with a 3D-printed diffuser and case form the display, with trivia questions and their answer as a QR code standing in for the punch-cards.He also added a pair of user consoles, so players can lock-in and answer before an ESP32-Cam reads the QR code and displays the answer on the LED matrix, after playing some suitable “thinking music” through a speaker.

As usual with [Michael]’s retrocomputing recreations, the level of detail here is fantastic. We especially like the custom buttons; controls like these seem to be one of his specialties judging by his slide switches and his motorized rotary switch.

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AT Keyboard Becomes Child’s Speaking Toy

January 17, 2021 by Jenny List 6 Comments

Just as cats find sitting on a keyboard to be irresistible, so do children find pressing their keys. After throwing some ideas around with other parents, [Peter] came up with the idea of transforming an old AT keyboard into a learning toy by making each key press “speak” its corresponding letter.

The donor keyboard is a nondescript late-80s AT compatible PC. Before readers imagine that a sought-after mechanical ‘board is being defiled, these were manufactured in their millions back then with exactly the same lackluster actions as modern cheap input devices. This one had plenty of space inside for an Arduino Nano that emulates an AT keyboard host and plays WAV file samples from an SD card to one of its PWM outputs. An op-amp low pass filter cleans up the noise from this rudimentary DAC, and feeds a little speaker through an audio amplifier. The keyboard supports both male and female voices, as well as a piano.

Hours of juvenile fun will no doubt result, but we can’t help wondering whether this could become the bane of a parent’s life in the manner of so many other noise-producing toys. Meanwhile, [Peter]’s work has graced these pages in the past, most recently with an automatic cooker hood.

You’re Going To Flip Out Over This Rocket League RC Car

January 15, 2021 by Lewin Day 10 Comments

Rocket League is a video game famous for being wildly popular despite being virtually unplayable without several hours practice. It involves hyper fast cars playing soccer, complete with the ability to flip, jump, and rocket boost into the ball. [mrak_ripple] decided he wanted some of that action in a real RC car, and set to work.

While rocket boosts were out of scope for this build, [mrak_ripple] was pretty confident he could build a jumping, flipping RC car modelled after the Rocket League Octane vehicle. Initial experiments involved a custom 3D printed spring mechanism, but the results were underwhelming. Instead, in the true hacker spirit, a jumping mechanism was taken from an existing toy, and installed in the car instead. This was combined with a mechanism built out of a brushless motor with a flywheel added to generate a flipping moment in mid-air.

The final result is impressive, with the car flipping relatively cleanly once refined and lightened from its original design. We’d love to see a two-axis build that can front- and back-flip as well. It’s a step up in complexity from the last build we saw from [mrak_ripple], the amusing mashed potato trebuchet. Video after the break.

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