Hydrogen Powered Nerf Blaster Is Dangerously Awesome

December 10, 2018 by Lewin Day 10 Comments

Nerf blasters have been around for decades now, exciting children and concerning parents alike. Most are powered by springs or compressed air, and are the ideal holiday toy for putting delicate family heirlooms at risk. Not content to settle for the usual foam-flinging sidearm, [Peter Sripol] decided to take things up a notch.

The build starts with a MEGA CYCLONESHOCK blaster, which uses the larger red NERF darts as ammunition. Water tanks are rigged to the outside, fitted with stainless steel electrodes. The original spring & plunger firing assembly is then removed, to make room for a firing chamber made out of copper pipe. A small taser-like device is used as an igniter. When the charging switch is pressed, current is passed through the electrodes in the water, which splits the water into hydrogen and oxygen gas. This is then passed to the firing chamber, where it can be ignited by the taser module, activated by the trigger.

Despite some issues with the blaster occasionally destroying darts due to what appears to be overpressure, it is capable of higher shot velocities than the stock blaster. For all its complexity, performance is somewhat hit and miss, but the cool factor of a handheld hydrogen bubbler is hard to ignore. [Peter] does note however that the combination of explosive gases and dangerous catalyst chemicals make this one build that’s probably best left to adults.

If this NERF hack isn’t dangerous enough, you might prefer these Taser darts instead. Video after the break.

[Thanks to Baldpower for the tip!]

Continue reading “Hydrogen Powered Nerf Blaster Is Dangerously Awesome” →

Energy Sipping Neodymium Sphere Keeps On Spinning

November 23, 2018 by Tom Nardi 16 Comments

At this point we’re sure you are aware, but around these parts we don’t deduct points for projects which we can’t immediately see a practical application for. We don’t make it our business to say what is and isn’t worth your time as an individual hacker. If you got a kick out of it, great. Learned something? Even better. If you did both of those things and took the time to document it, well that’s precisely the business we’re in.

So when [Science Toolbar] sent in this project which documents the construction of an exceptionally energy efficient spinning neodymium sphere, we knew it was our kind of thing. In the documentation it’s referred to as a motor, though it doesn’t appear to have the torque to do any useful work. But still, if it can spin continuously off of the power provided by a calculator-style photovoltaic cell, it’s still a neat trick.

But how does it work? It starts by cracking open one of those little solar powered toys; the ones that wave or dance around as soon as any light hits the panel in their base. As [Science Toolbar] explains, inside these seemingly magical little gadgets is a capacitor and the classic black epoxy blob that contains an oscillator circuit. A charge is built up in the capacitor and dumped into a coil at roughly 1 Hz, which provides just enough of a push to get the mechanism going.

In the video after the break, [Science Toolbar] demonstrates how you can take those internals and pair it with a much larger coil. Rather than prompting a little sunflower or hula girl to do its thing, the coil in this version provides the motive force for getting the neodymium sphere spinning. To help things along, they’re even using a junk box zero friction magnetic bearing made up of a wood screw and a magnetized screwdriver tip.

It’s an interesting example of how a tiny charge can be built up over time, and with a nice enough enclosure this will make for a pretty cool desk toy. We’ve previously seen teardowns of similar toys, which revealed a surprising amount of complexity inside that little epoxy blob. No word on whether or not the version [Science Toolbar] cannibalized was quite so clever, however.

Continue reading “Energy Sipping Neodymium Sphere Keeps On Spinning” →

Move Over Strandbeest, Here’s Strider!

November 23, 2018 by Elliot Williams 20 Comments

Father-and-son team [Wade] and [Ben Vagle] have developed and extensively tested two great walker designs: TrotBot and the brand-new Strider. But that’s not enough: their website details all of their hard-earned practical experience in simulating and building these critters, on scales ranging from LEGO-Technic to garage-filling (YouTube, embedded below). Their Walker ABC’s page alone is full of tremendously deep insight into the problem, and is a must-read.

These mechanisms were designed to be simpler than the Jansen linkage and smoother than the Klann. In particular, when they’re not taking a stroll down a beach, walker feet often need to clear obstacles, and the [Vagles’] designs lift the toes higher than other designs while also keeping the center of gravity moving at a constant rate and not requiring the feet to slip or slam into the ground. They do some clever things like adding toes to the bots to even out their gaits, and even provide a simulator in Python and in Scratch that’ll help you improve your own designs.

If you wanted a robot that simply moved, you’d use wheels. We like walkers because they look amazing. When we wrote [Wade] saying that one of Trotbot’s gaits looked animal-like, he pointed out that TrotBot got its working name from a horse-style gait (YouTube). Compared to TrotBot, the Strider family don’t have as much personality, but they run smoother, faster, and stronger. There’s already a 3D-printing-friendly TrotBot model out there. Who’s going to work something up for Strider?

How much do we love mechanical walkers? Enough to post about bicycles made with Jansen linkages, remote-controlled toy Strandbeests both with weaponry and without, power-drill-powered walking scooters, and of course basically anything that Theo Jansen is up to.

If a trip to [Wade] and [Ben]’s website doesn’t get you working on a walker project, physical or virtual, we don’t know what will.

(And from the editorial department of deconfusion: the image in the banner is TrotBot, but it was just too cool to not use.)

Continue reading “Move Over Strandbeest, Here’s Strider!” →

Centurion Bridge Layer, Now In RC

November 14, 2018 by Lewin Day 1 Comment

Radio controlled models are great fun. Most of us have had a few RC cars as children and maybe dabbled with the occasional helicopter or drone. It’s a rare breed of modeler, however, that gets to drive a radio-controlled bridge laying tank.

The lads prepare to fight the good fight.

The model is a replica of the British Centurion Bridgelayer – a modified tank designed to allow mechanized units to readily cross rivers and similar obstacles in European battlefields. While the genuine article relied on hydraulics, the RC version takes a different tack. [hawkeye3guns] built custom linear actuators out of motors, gears, and brass to deploy the bridge.

The build shows other smart techniques of the enterprising modeler. Rather than start from scratch, the Centurion is built on a modified KV tank hull. After the modifications were complete, the tank received a lick of paint in the requisite British Army green. The final result is rather impressive.

It goes to show what can be achieved with some off-the-shelf parts and ingenuity. We’ve seen other impressive RC tanks before – like this French build with a homebrew targeting computer.

The Mighty D Battery Becomes A USB Powerbank

November 13, 2018 by Brian Benchoff 63 Comments

[Jan] is one of those people who’s always playing around with synthesizers, and in this day and age, that means a lot of USB cables supplying power. If you want to make a synth setup portable, your best option is looking at USB powerbanks with their fancy lithium cells. These will work just fine, but remember: you can buy D cells just about anywhere, and they actually hold a ridiculous amount of energy. They’re cheap albeit one-use and disposable, so why not build a USB power bank out of a massive pair of batteries?

The build started off, naturally, with a pair of Energizer D cells that hold 20,000mAh. A battery holder for these cells is cheap and easy to source, leaving the only other needed component a cheap 5V boost converter. This was simply hot glued to the back of the battery holder in parallel, a simple switch was added, and the entire thing was fitted in a neat little 3D printed case that looks like a car (motorcycle?) battery.

Testing the with a phone revealed this thing will charge at 570mA from 3V, which is more than sufficient for [Jan]’s needs. Sure, using disposable batteries in 2018 is more than a little wasteful, but a project like this is meant to be a simple solution to the problem of providing power to USB devices anywhere. You can get D cell batteries everywhere, and what this build produces in damage to the environment is more than made up for in its convenience.

Lego Tardis Spins Through The Void

November 12, 2018 by Rich Hawkes 8 Comments

Using LEGO Technic gears and rods seems like a great way of bringing animation to your regular LEGO creation. Using gears and crank shafts you can animate models from your favorite TV show or movie like LEGO kinetic sculpture maker, [Josh DaVid] has done when he created a spinning TARDIS. Crank the handle and the sculpture spins through space and time.

The large gear stays in place. The hidden gears, turned by the crank, rotate a shaft from below that goes through the large gear making the TARDIS rotate around the main axis. Connected to the TARDIS model is a smaller gear, at an angle, that meshes with the larger, stationary, gear. This smaller gear is what causes the TARDIS to rotate around its own axis while the whole thing rotates around the main axis. If your hand gets too tired, you can substitute a LEGO motor.

It’s a neat effect, and you can get the plans [Josh]’s Etsy page. The best part, however, is that you can get a set with all the parts as well! The TARDIS is a popular item here and we’ve had plenty of projects with it as the focus: Everything from a tree topper to sub-woofers. The only question we have, of course, is, ‘Is it bigger on the inside?’

Continue reading “Lego Tardis Spins Through The Void” →

Mini LEGO Technic Tank Patrols Your Desk Under ESP32 Control

November 1, 2018 by Tom Nardi 11 Comments

We probably don’t have to tell the readers of Hackaday that LEGO isn’t just for kids; we’ve seen plenty of projects that live in an enclosure made of the multi-color bricks, and let’s not even get started on the Mindstorms builds we’ve seen over the years. But while LEGO (and especially the Technic product line) is fine for prototyping and putting together quick projects, the stock electronic components aren’t exactly top of the line. Which is why [Jason Kirsons] has been working on bridging the gap between LEGO and “real” parts.

His LEGO Technic tank is a perfect example of this principle. While the tank design itself is standard LEGO fare, he’s gone all in on the electronics. With an Adafruit Feather ESP32, custom motor controller board, and NEMA 8 steppers with 3D printed Technic adapters, this little tank has a lot more going on under the hood than you might expect. While this project is more a proof of concept than anything, the methods [Jason] demonstrates might be something to consider the next time you’re building with Billund’s best.

[Jason] chose the Feather ESP32 because of its small size, but you could get away with a generic board if you’re not trying to compress everything down into such a small footprint. Of course, if you go with another board you won’t be able to use the PCB he’s designed which attaches to the Feather and holds four Pololu DRV8835 motor drivers.

Easily the most broadly applicable element of this project is the work [Jason] has done designing adapter plates that let you use NEMA 8 motors with LEGO Technic parts. He’s put the adapters up on Thingiverse, for anyone looking for a drop-in solution to give their Technic creations a bit more oomph (technical term).

LEGO has a long history with hackers and makers. We’ve covered some absolutely incredible projects built with the famous construction set, and we don’t see any sign of it slowing down in the future.

Continue reading “Mini LEGO Technic Tank Patrols Your Desk Under ESP32 Control” →