What is this world coming to when you can’t even enjoy sitting in your living room without some jamoke flying a drone in through the window? Is nothing sacred? Won’t someone think of the children?
Apparently [Drew Pilcher] did, and the result is this anti-drone sentry gun. It’s a sturdily built machine – one might even say it’s overbuilt. The gimbal is made from machined steel pieces, and the swivels are a pair of Sherline stepper-controlled rotary tables with 1/40 of a degree accuracy selling for $400 each. Riding atop that is a Nerf rifle, which is cocked by a stepper-actuated linear slide, as well as a Kinect for object tracking. The tracking app is a little rough – just OpenCV hacked onto the Kinect SDK – but good enough for testing. The gun tracks as smoothly as one would expect given the expensive hardware, and the auto-cocking feature works well if a bit slowly. Based as it is on Nerf technology, this sentry is only indicated for the control of the micro-drones seen in the snuff video below, but really, anyone afflicted by indoor infestations of Phantoms or Mavics has bigger problems to worry about.
Over-engineered? Perhaps, but it’s better than letting the menace of indoor drones go unanswered. And it’s far from the first sentry gun we’ve seen, targeting everything from cats to squirrels using lasers, paintballs, and even plain water.
Thieves beware. If you prowl around [Matthew Gaber]’s place, you get soaked by his motion activated super-squirter. Even if he’s not at home, he can aim and fire it remotely using an iPhone app. And for the record, a camera saves photos of your wetted-self to an SD card.
The whole security system is handled by three subsystems for target acquisition, photo documentation, and communications. The first subsystem is centered around an ESPino which utilizes a PIR sensor to detect motion. It then turns on a windscreen washer pump and uses pan and tilt servos to squirt water in a pattern toward the victim.
The target acquisition hardware also sends a message to the second subsystem, an ArduCAM ESP8266 UNO board. It takes a burst of photos using an ArduCAM Mini Camera mounted beside the squirter outlet. The UNO can also serve up a webpage with a collection of the photos.
The final subsystem is an iPhone app which talks to both the ESPino and the UNO board. It can remotely control the squirter and provide a video feed of what the camera sees.
One detail of the build we really enjoyed is the vacuum relief valve he fabricated himself. It prevents siphoning through the pump when it’s not on. Don’t miss a demo of the squirter in action after the break.
We love taking on new and awesome builds, but finding that second part (the “awesome”) of each project is usually the challenge. Looks like [Nathan Seidle] is making awesome the focus of the R&D push he’s driving at Sparkfun. They just put up this safe cracking project which includes a little gamification.
The origin story of the safe itself is excellent. [Nate’s] wife picked it up on Craig’s List cheap since the previous owner had forgotten the combination. We’ve seen enough reddit/imgur threads to not care at all what’s inside of it, but we’re all about cracking the code.
The SparkX (the new rapid prototyping endeavor at Sparkfun) approach was to design an Arduino safe cracking shield. It has a motor driver for spinning the dial and can drive a servo that pulls the lever to open the door. There is a piezo buzzer to indicate success, and the board as a display header labeled but not in use, presumably to show the combination currently under test. We say “presumably” because they’re not publishing all the details until after it’s cracked, a process that will be live streamed starting Wednesday. This will keep us guessing on the use of that INA169 current sensor that plugs into the safecracking shield. There is what appears to be a reflectance sensor above the dial to keep precise track of the spinning dial.
Electrically this is what we’d expect, but mechanically we’re in love with the build. The dial and lever both have 3D printed adapters to interface with the rest of the system. The overall framework is built out of aluminum channel which is affixed to the safe with rare earth magnets — a very slick application of this gear.
The gamification of the project has to do with a pair of $100 giveaways they’re doing for the closest guess on how long it’ll take to crack (we hope it’s a fairly fast cracker) and what the actual combination may be. For now, we want to hear from you on two things. First, what is the role of that current sensor in the circuit? Second, is there a good trick for optimizing a brute force approach like this? We’ve seen mechanical peculiarities of Master locks exploited for fast cracking. But for this, we’re more interested in hearing any mathematical tricks to test likely combinations first. Sound off in the comments below
[Brittliv] made the mistake of getting her friends into Nerf weaponry, and so began the race to mutually secured destruction via foam darts. She may have the upper hand in this war, because her Nerf Vulcan sentry gun is both incredibly powerful and is able to be operated autonomously with a webcam featuring a friend or foe identification system.
The azimuth and elevation mount for the gun is made out of plywood, with each axis controlled by a single servo attached to an Arduino. Of course a stock Nerf gun would be fairly boring, so [BrittLiv] increased both the voltage going to the gun’s motor and the strength of the gun by replacing a 2kg spring with a 5kg spring.
Targets are tracked with a webcam using Processing and a bit of code from Project Sentry Gun. One interesting feature is a friend or foe tracking system; if the gun sees someone wearing a t-shirt with the Instructables logo, the target is identified as a friend and is not brutally mowed down with plastic darts.
These greeting cards must be the product of a mechanical engineer run amok. They come with a crank and are designed to entertain with their simple, yet elegant movements. [Thanks Phil]
Magnetic card stripe reader
[JP] built an Arduino based magnetic card reader. It uses off-the-shelf parts but if you don’t mind buying the components this will get you up and running in no time. If you want more info there’s also this Teensy based version.
Homemade Airsoft sentry gun
This sentry gun has an amazingly fast firing rate that can continue for quite a while, thanks to the big flashlight housing that is holds a lot of ammo. [Thanks David]
With exams behind him [Adam Greig] had time to make a Nerf sentry gun. It’s actually quite easy to pull everything together. He’s got a netbook running Motion, an open source motion sensing program for use with a webcam. When movement is detected an Arduino, connected via a USB cable, actuates a servo to pull the trigger of the gun. The turret itself has seen a battery upgrade that increases the firing speed. It’s fun to see hardware prototyping done with a few pencils and a fist full of cable ties. Check it out after the break.