[Mehdi’s] Shocking Stun Gun Tutorial

October 25, 2014 by Theodora Fabio 25 Comments

[Mehdi Sadaghdar] never lets little things like fire, shocks, or singed fingers get in the way of his projects. His latest is a tutorial on making a simple electroshock device. A stun weapon creates a very high voltage, and is used in law enforcement to temporarily disable a person. [Mehdi] stresses repeatedly to not use this on anyone. If you do, he won’t like you anymore. Of course, if you’ve seen any of his previous videos, you know he’ll shock himself and set something on fire before the project is complete.

To create his stunner, [Mehdi] used a car ignition to produce a high voltage. The igniton coil, which is a specialized transformer, allowed him to generate the >10000V output needed for the stunner. The coil has a 60:1 ratio and is powered by a 12V DC supply. Since a coil is a short at DC, the system only creates a high voltage pulse when power is disconnected. However, the pulse was too short to create a satisfying arc. [Mehdi] added a capacitor, creating an LC circuit that oscillates as the charge decays, creating a nicer spark. He then used an RC circuit and a relay to create a simple oscillating switch. For the finishing touch, he created a spark gap on the secondary of the transformer with two nails. In typical [Mehdi] fashion, he nearly fried his digital caliper in the process.

The end result is a nice spark that warms the cockles of [Mehdi’s] fibrillating heart. We commend him for being such a brave masochist in the name of science. Check out his tutorial after the break!

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Capacitive Garage Door Opener Hides Behind Your Dash

October 25, 2014 by Rick Osgood 26 Comments

[Pyrow] wanted to upgrade his garage door opener remote. It worked just fine, but changing those tiny batteries out can be an inconvenience. Plus, the remote control was taking up valuable storage space and would always rattle around while driving. [Pyrow] decided to make use of an Omron E2K-F10MC2 capacitive touch sensor to fix these issues.

[Pyrow’s] circuit still makes use of the original remote control. He just added some of his own components to get it to do what he wanted. The circuit is powered by the car’s battery, so it never needs a battery replacement. The circuit is protected with a fuse and the power is regulated to prevent electrical spikes from burning up the original remote control. The actual circuit is pretty simple and uses mostly discrete components. It’s all soldered onto proto board to keep it together. He only had to solder to three places on the original remote control in order to provide power and simulate a button press.

Next, [Pyrow] took his dash apart. He used double-sided tape to attach the touch sensor to the back of the dash. After securing the electronics in place with tape, he now has a working hidden garage door opener. Full schematics are available in the writeup linked above. Also, be sure to watch the demonstration video below.

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Using Kinect To Play Super Mario Bros 3 On NES Ensures Quick Death

October 25, 2014 by Rich Bremer 5 Comments

Why do only the new game consoles get all the cool peripherals? Being a man of action, [Paul] set out to change that. He had a Kinect V2 and an original Nintendo and thought it would be fun to get the two to work together.

Thinking it would be easiest to emulate a standard controller, [Paul] surfed the ‘net a bit until he found an excellent article that explained how the NES controller works. It turns out that besides the buttons, there’s only one shift register chip and some pull up resistors in the controller. Instead of soldering leads to a cannibalized NES controller, he decided to stick another shift register and some resistors down on a breadboard with a controller cable connected directly to the chip.

An Arduino is used to emulate the buttons presses. The Arduino is running the Firmata sketch that allows toggling of the Arduino pins from a host computer. That host computer runs an application that [Paul] wrote himself using the Kinect V2 SDK that converts the gestures of the player into controller commands which then tells the Arduino which buttons to ‘push’. This is definitely a pretty interesting and involved project, even if the video does make it look very challenging to rescue Princess Toadstool from Bowser and the Koopalings!

If you’d like to help the project or just build one for yourself, check out the source files on the Kinect4NES GitHub page.

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[Harrison Krix’s] Marriott Chariot

October 25, 2014 by Marsh 6 Comments

Atlanta’s Mini Maker Faire had plenty of booths to keep visitors busy, but the largest spectacle by far was the racetrack smack-dab in the middle, and you’d be hard pressed to find a more eye-catching contender than [Harrison Krix’s] vehicle: the Marriott Chariot.

If [Krix’s] name looks familiar, that’s because he’s the master artisan behind Volpin Props, and is responsible for such favorites as the Futurama Holophonor replica and the Daft Punk helmet. (Actually, he made the other one, too).

The Chariot is yet another competitor in the Power Racing Series, an event that keeps popping up here on Hackaday. [Krix] drew inspiration from this Jeep build we featured earlier in the summer, and went to work sourcing an old plastic body to get started. The frame is 16 gauge square tubing, with a custom motor mount machined from 3/16 steel. After welding the chassis together, [Krix] chopped up a small bicycle to snag its head tube and headset bearings. A pair of sealed lead acid batteries fit horizontally in the frame, providing a slightly lower center of gravity.

[Krix] has a keen eye for precision and his build journal shows each step of his meticulous process. But, you ask, why “Marriott Chariot?” and why does the car look like someone threw up a kaleidoscope? Read on beyond the break, dear reader, to learn the Chariot’s origin and to see a video of it winding around the track.

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A Compact Underwater Vehicle: The Nanoseeker

October 25, 2014 by Ethan Zonca 36 Comments

The Nanoseeker is a compact underwater vehicle in a torpedo-like form factor. [John] designed the Nanoseeker as completely enclosed vehicle: both the thruster and the control fins are all housed within the diameter of the tube. The thruster is ducted with vents on the sides and control fins integrated into the back of the duct assembly.

[John] designed a compact PCB to drive the vehicle, which includes an STM32F4 alongside several sensors. An MPU-9150 provides IMU functionality and two dual motor driver ICs from TI control the throttle and the control fins. [John] also added a Bluetooth radio for remote control functionality. For those who want a closer look, an image of the schematic is up on his blog.

The board is running MicroPython, which is a small Python implementation optimized for microcontrollers. Although [John]’s hardware platform looks great, he’s still getting started on his software. We look forward to seeing how his project develops, as his project is one of the smallest underwater vehicles we’ve seen.

[via Dangerous Prototypes]

An SDK For The ESP8266 WiFi Chip

October 25, 2014 by Brian Benchoff 70 Comments

The ESP8266 is a chip that turned a lot of heads recently, stuffing a WiFi radio, TCP/IP stack, and all the required bits to get a microcontroller on the Internet into a tiny, $5 module. It’s an interesting chip, not only because it’s a UART to WiFi module, allowing nearly anything to get on the Internet for $5, but because there’s a user-programmable microcontroller in this board. If only we had an SDK or a few libraries…

The ESP8266 SDK is finally here. A complete SDK for the ESP8266 was just posted to the Expressif forums, along with a VirtualBox image with Ubuntu that includes GCC for the LX106 core used in this module.

Included in the SDK are sources for an SSL, JSON, and lwIP library, making this a solution for pretty much everything you would need to do with an Internet of Things thing. As far as LX106 core is concerned, there’s example code for using the spare pins on this board as GPIOs, I2C and SPI busses, and a UART.

This turns the ESP8266 into something much better than a UART to WiFi module; now you can create a Internet of Things thing with just $5 in hardware. We’d love to see some examples, so put those up on hackaday.io and send them in to the tip line.

Use A Cheap PIN Diode As A Geiger Counter

October 25, 2014 by Elliot Williams 51 Comments

After the Fukushima nuclear power plant disaster, radiation measurement became newly relevant for a lot of people. Geiger-Müller tubes, previously a curiosity, became simultaneously important and scarce.

Opengeiger.de (English-language version here) has complete instructions for making a Geiger counter without a Geiger-Müller tube. Instead, this counter uses a PIN photodiode and some carefully chosen operational amplifiers. The total cost of such a device is significantly cheaper than the alternative: under $1 for the diode and around $5 for the rest. And since the PIN photodiode in question is used in many other devices, it’s not a niche component like a Geiger tube is.

The secret sauce is in component selection and tuning. Opengeiger uses the BPW34 diode because it is relatively common and has a large surface area, but also because it has a very low capacitance when reverse-biased. The first-stage opamp choice is also fairly critical. Considering that an average gamma radiation event produces only around 10 nanoamps for about 50 microseconds, a lot of amplification (100,000x), low noise, and high bandwidth are a must.

If you want to get started with this project, you could first browse through the explanation (PDF) to get an overview of the project’s goals, read up on all the technical considerations (PDF) or just head straight for the DIY instructions for the “Stuttgarter Geigerle” (PDF, schematic is on the last page). All of the documentation is chock-full of relevant references and totally worth the read.