Planet Arduino

Well, here it is: a shoe-in for the new world’s largest NERF gun. (Video, embedded below.) The Guinness people haven’t shown up yet to award [Michael Pick], but at 12.5 feet, this baby is over twice as long as the current record holder, which belongs to former NASA mechanical engineer Mark Rober and his now-puny six-foot six-shooter.

We have to wonder if it is technically bigger than the six-shooter, because they seem to be roughly the same scale, except that [Michael] chose a much bigger model to start from. The main body is made from wood, and there are a ton of 3D-printed details that make it look fantastically accurate. The whole thing weighs over 200 pounds and takes at least two people to move it around. We especially love the DIY darts that [Michael] came up with, which are made from a PVC tube inside a section of pool noodle, topped off with a 3D printed piece for that distinctive orange cap.

Propelling those darts at around 50 MPH is a 3,000 PSI air tank connected to an Arduino Pro Mini that controls the trigger and the air valves. While [Michael] hasn’t run the thing quite that high, it does plenty of damage in the neighborhood of 40-80 PSI. As you’ll see in the video after the break, this is quite the ranged weapon. Watch it blow a hole clean through a sheet of drywall and much more.

Want to build something with a bit more stealth? Make it death from above with a NERF quadcopter.

As has been made abundantly clear by the advertising department of essentially every consumer electronics manufacturer on the planet: everything is improved by the addition of sensors and a smartphone companion app. Doesn’t matter if it’s your thermostat or your toilet, you absolutely must know at all times that it’s operating at peak efficiency. But why stop at household gadgets? What better to induct into the Internet of Things than 600 year old samurai weaponry?

Introducing the eKatana by [Carlos Justiniano]: by adding a microcontroller and accelerometer to the handle of a practice sword, it provides data on the motion of the blade as it’s swung. When accuracy and precision counts in competitive Katana exhibitions, a sword that can give you real time feedback on your performance could be a valuable training aid.

The eKatana is powered by an Adafruit Feather 32u4 Bluefruit LE and LSM9DS0 accelerometer module along with a tiny 110 mAh LiPo battery. Bundled together, it makes for a small and unobtrusive package at the base of the sword’s handle. [Carlos] mentions a 3D printed enclosure of some type would be a logical future improvement, though a practice sword that has a hollow handle to hold the electronics is probably the most ideal solution.

A real-time output of sword rotation, pitch, and heading is sent out by the Adafruit Feather over BLE for analysis by a companion smartphone application. For now he just has a running output of the raw data, but [Carlos] envisions a fully realized application that could provide the user with motions to perform and give feedback on their form.

Incidentally this isn’t the first motion-detecting sword we’ve ever covered, but we think this particular incarnation of the concept might have more practical applications.

With All Hallow’s Eve looming close, makers have the potential to create some amazing costumes we’ll remember for the rest of the year. If you’re a fan of the hugely addict-*cough* popular game Minecraft, perhaps you’ve considered cosplaying as your favorite character skin, but lacked the appropriate props. [Graham Kitteridge] and his friends have decided to pay homage to the game by making their own light-up Minecraft swords.

These swords use 3D-printed and laser-cut parts, designed so as to hide the electronics for the lights and range finder in the hilt. Range finder? Oh, yes, the sword uses an Arduino Uno-based board to support NewPixels LEDs and a 433Mhz radio transmitter and receiver for ranged detection of other nearby swords that — when they are detected — will trigger the sword to glow. Kind of like the sword Sting, but for friendlies.

All of the files for the parts are available on the project’s Thingverse page and the board setup can be purchased here. If you want to have some fun controlling the real world from inside Minecraft, check out how this fan uses it to turn on lamps in their home.

Looks like another shot has been fired in the simmering Coil Gun Control War. This time, [Great Scott] is taken to the discrete woodshed with a simplified and improved control circuit using a single CMOS chip and a few transistors. Where will it end? Won’t somebody think of the children?

The latest salvo is in response to [GreatScott]’s attempt to control a DIY coil gun with discrete logic, which in turn was a response to comments that he took the easy way out and used an Arduino in the original build. [Great Scott]’s second build was intended to justify the original design choice, and seemed to do a good job of explaining how much easier and better the build was with a microcontroller. Case closed, right?

Nope. Embedded designer [fede.tft] wasn’t sure the design was even close to optimized, so he got to work — on his vacation, no less!’ He trimmed the component count down to a single CMOS chip (a quad Schmitt trigger NAND), a couple of switching transistors, the MOSFETs that drive the coils, and a few passives. The NANDs are set up as flip-flops that are triggered and reset by the projectile sensors, which are implemented as hardwired AND gates. The total component count is actually less than the support components on the original Arduino build, and [fede.tft] goes so far as to offer ideas for an alternative that does away with the switching transistors.

Even though [fede.tft] admits that [GreatScott] has him beat since he actually built both his circuits, hats off to him for showing us what can likely be accomplished with just a few components. We’d like to see someone implement this design, and see just how simple it can get.

A common complaint in the comments of many a Hackaday project is: Why did they use a microcontroller? It’s easy to Monday morning quarterback someone else’s design, but it’s rare to see the OP come back and actually prove that a microcontroller was the best choice. So when [GreatScott] rebuilt his recent DIY coil gun with discrete logic, we just had to get the word out.

You’ll recall from the original build that [GreatScott] was not attempting to build a brick-wall blasting electromagnetic rifle. His build was more about exploring the concepts and working up a viable control mechanism for a small coil gun, and as such he chose an Arduino to rapidly prototype his control circuit. But when taken to task for that design choice, he rose to the challenge and designed a controller using discrete NAND and NOR gates, some RS latches, and a couple of comparators. The basic control circuit was simple, but too simple for safety — a projectile stuck in the barrel could leave a coil energized indefinitely, leading to damage. What took a line of code in the Arduino sketch to fix required an additional comparator stage and an RC network to build a timer to deenergize the coil automatically. In the end the breadboarded circuit did the job, but implementing it would have required twice the space of the Arduino while offering none of the flexibility.

Not every project deserves an Arduino, and sometimes it’s pretty clear the builder either took the easy way out or was using the only trick in his or her book. Hats off to [GreatScott] for not only having the guts to justify his design, but also proving that he has the discrete logic chops to pull it off.

[Robin Baumgarten] likes to play dangerously. His latest creation, Knife To Meet You cuts to the quick of cooperative gaming. 3 humans play together against the machine. The object of the game is to hold your button down as long as possible. The game makes this difficult by sweeping a knife across the play field, right at finger level. (Video below.)

Knife to meet you is controlled by a flesh eating Arduino. In addition to reading the controls and driving a servo to move the knife, the Arduino also displays encouraging messages on a 2×20 character LCD.

The idea is to scare people, not to actually slice them up. To this end, the knife is actually a capacitive sensor. When the game detects the knife has contacted soft human flesh, it stops the knife before blood starts flowing. The game indicates a player has been defeated by making several chopping motions toward the loser. If the losing player still has all their digits, a new round begins.

The was created as part of a 24 hour game jam. The final product is quite nice, built into a wood case that closes up for travel. It even has a carrying handle, so you can bring it to parties and find fresh victims players.

We’re not sure what it is about knives and Arduinos. It was only a few months ago that we saw an Arduino driving a knife wielding tentacle. Could the world’s friendliest microcontroller board be turning on us?

There are certain topics that cause people to have knee-jerk reactions: Try asking a crowd which Star Trek was best or–around here–take a stance for or against the Arduino and you’ll see what we mean. Certainly people polarize quickly when you talk about a 3D printed gun. However, if anyone can sneak [xtamared’s] 3D printed rail gun through airport security, then some guards will have to be fired. It looks like a cool prop from a bad movie, but (as you can see in the videos below) it can project a conductive slug into a decidedly low-tech target.

There aren’t many build details, although you can deduce a few things from the pictures and the captions. At the rear of the gun is a paintball tank that gets the slug moving before it hits the rails which further accelerate the projectile. The electric part is Arduino-based and the very prominent capacitors at the front end can deliver 1800 joules of energy (and add 20 pounds of weight to the gun).

It looks like a lot of the gun is printed in PLA, but the electronics case is ABS (doubtlessly to avoid exposing PLA to the heat sink attached to the 1500V rectifier). The paintball tank’s pressure gets the slug moving to 100 meters/second before it hits the rails. In early testing, a PLA part and a steel bolt broke, so the items got replaced with polycarbonate and nylon. Apparently, parts of the injector are polypropylene.

The rails themselves are made for replacement, since each shot damages them a bit. They are constructed of garolite (fiberglass and resin composite sort of like PCB material) and wrapped in carbon fiber. That’s one of the things that impressed us–this is a highly multimedia build with different materials used to do different jobs, digital and high voltage electronics, and pneumatics.

We’ve covered a lot of rail guns over the years and we’ve looked at robot-mounted coil guns, too. If you want something more portable, check out this tiny rail gun (although the Geocities cache for the article is dead, but there are others).

Thanks [caffeine_addict] for the tip!

You know that guy in the next cube is sneaking in when you are away and swiping packs of astronaut ice cream out of your desk. Thanks to [Kevin Thomas], if you have an Arduino and a 3D printer, you can build a rubber band sentry gun to protect your geeky comestibles. You’ll also need some metric hardware, an Arduino Uno, and a handful of servo motors.

The video shows [Kevin] manually aiming the gun, but the software can operate the gun autonomously, if you add some sensors to the hardware.  The build details are a bit sparse, but there is a bill of material and that, combined with the 3D printing files and the videos, should allow you to figure it out.

We couldn’t help but wish for a first person view (FPV) camera and control via a cell phone, so you could snipe at those ice cream thieves while hiding in the broom closet. On the other hand, if you got the gun working, adding the remote wouldn’t be hard at all. You probably have a WiFi FPV camera on your quadcopter that finally came out of that tree and there’s lots of ways to do the controls via Bluetooth or WiFi.

Not that you don’t have options. But here at Hackaday HQ, we have lots of rubber bands and not so many green pigs. If you’d rather shoot paintballs, be careful you don’t accidentally repaint the insides of your cube.

Mama, just killed hit a man, Put a gun against his head, Pulled my trigger, now he’s dead.
Mama, life had just begun, But now I’ve gone and thrown it all away…

This latest piece of half-art / half-prototype from one of our favorite hacker-artists [vtol] is a billy club equipped with a GSM-module. It automatically sends an SMS to your mother with the text: “Mom, I hit a man.” He calls it the Antenna:

The idea of the project is to create a device which strictly controls the cruelty of police. As all the standard methods of control are ineffective, this project suggests the maternity as the last stronghold of human kindness and responsibility.

An Arduino is equipped with a piezo sensor to detect impact, and a GSM shield takes care of the texting. It’s an interesting concept, similar to requiring police officers to wear body cameras. You can debate the practicality, but we’re always interested in hearing about weapons monitoring tech concepts. One of our favorites has always been the DNA gun from (Judge) Dredd. Did you know there was an Internet Movie Firearms Database? But we digress, check out [vtol’s] demo video:

Speaking of those body cameras — [vtol] also made an 8-bit photo gun not so long ago…

And since Bohemian Rhapsody is now stuck in your head (you’re welcome) here’s that little ditty:

Taking the time to build a reactive target range really adds to the fun of toy weapons. It lets you move beyond just point and shoot to actual games of skill.

The project is anchored by an Arduino board. It connects to a piezo element on the back of each of these sheet metal targets. Detecting when a projectile hits the target works pretty much the exact same way the ever popular Knock-block works. To provide interactive enjoyment each target has an LED which, when lit, indicates that the target is active. From here it’s just a matter of coding to add different challenges. So far [Viktor Criterion] has implemented quick draw, timed, and rapid fire modes. The demo after the break shows off everything, including the slick modular design he came up with to make the system portable.

We’d love to see these targets mounted on motorized tracks. Each round would have the targets moving closer to you at a faster pace to keep you on your toes.