First things: there are no servo motors. No motors or any mechanical moving parts in this project.

There are 4 HC-SR04 ultrasonic sensor units, only one is working as transmitting – pinging module and receiver simultaneously, 3 others are just receivers. Arduino DUE, of course, is a prime violin of the whole project. Small prototype board has an additional 4-channel buffer amplifier (MCP6024).

Technical specification ( approximately ):

• Scanning range 3 m, limited very low power and sensitivity of the HC-SR04 devices.
• Spacial XY resolution depends on a distance, has to be determined.  Two object should be position at least 5 cm apart and not on the same spherical surface around sensor board.
• Directivity diagram +-30 degree, or so.
• Spacial Z – (distance) resolution 12 um. No typo error, micrometers.
• Time to complete full scan 16 milliseconds, frame rate may vary from 60 Hz down to 10 Hz if there is strong reverberation.

Have to say, that ultrasonic units were slightly modified, to brought out an analog signal (40 kHz) before it gets quantization in the local uCPU.  After amplification, 4-channels are digitized by arduino’s ADC (12-bits 1 MSPS).

Fast Fourier Transform, not much differs from the published on this blog library. I’m not ready to disclose complete signal processing algorithm, and is not publishing a code, at this time. Nevertheless, I don’t mind to answer reasonable /meaningful questions.

Video: have to practice more -);

A few comments on a video clip. I intentionally use a pen to draw a picture, even it’s almost violate the basic of the physics, because reflective area of the pen practically equals to wave length, 8.5 mm for 40 kHz in the air. You can see, that arduino is loosing track on a few occasions. Distance ~ 1m.

Computer is running Linux with regular “mtPaint 3.40″ from official source. Software is receiving a mouse commands, as its has no idea where this commands come from. In the same way, if you draw a picture manually. To interface with a host, arduino emulates a left button and XY move mouse commands using “build-in” mouse driver, and I copy ButtonMouseControl example from IDE.

The surface of the touch screen is “virtual”, first things arduino does after I send a command over serial monitor console to start a drawing, is “search – scan” an object. Whatever it finds first, the closest one, would be “locked” and distance to this object is interpreted as “touched – non touched”. This is first try, and I was not pushing hard on the gesture pattern recognition yet. But as you can guess, there is no limits to “slide” “rotate” “scroll” etc movement discrimination, with only one exception. There is no “multi-touch”, as I mentioned in the specification section, two object has to be 5 cm apart. This limitation is introduced by two shortcomings of the current hardware design. First one, because there is no phase array, only one unit is transmitting ( in the middle on right side ), so there is no way arduino could identify two objects on the same sphere. Second, is low sampling rate of the ADC. In order to “shrink” XY spatial resolution down to wave length (8.5 mm), sampling rate has to be at least 6 MSPS or so.

Tracking update rate (scan frame rate – don’t confuse with a video)  is set to 32 fps.

Photo:

 eddited: 14 Aug. 2014       “New technology is rising!”

Second video clip is posted, that demonstrates better tracking stability over bigger distance range. 

With the severe drought going on in California with no end in sight, [TVMiller] decided he could put an Arduino and a toilet together to try and save at least a few gallons of water per day. The invention fills a toilet to the minimum level, saving around two gallons per day for the average “user”.

A typical toilet functions by using gravity and moving water to create a vacuum, sucking the waste down and out of the toilet. As long as there is nothing, uh, solid in the bowl, the toilet will be able to function on the reduced amount of water. The Arduino cuts the flow of water off before the toilet fills up the entire way.

In the event that anyone -ahem- needs the toilet’s full capacity, there is a button connected to the Arduino that fills the reservoir to capacity. [TVMiller] notes that if 1,825 hackers installed this device on their toilets, we could save a million gallons of water per year and be well on our way to saving the planet.

The project site is full of more information and puns for your viewing pleasure. We might suggest that the “2” button would be very easy to integrate with the toilet terror level indicator as well.

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So you couldn't get your hands on a nice virtual reality headset like the Oculus Rift, but you'd still like something a little fancier than a cardboard display. Are you out of luck? Not if Noe Ruiz has anything to say about it. He has posted instructions at Adafruit for do-it-yourself 3D-printed goggles that can be used for either VR or as a simple wearable screen. The design mates an Arduino Micro mini computer with a display, a motion sensor and lenses; the 3D printing both adds a level of polish and lets you tailor the fit to your cranium. This definitely isn't the cheapest project (about $231 in parts) or the easiest, but it will give you head-tracking VR without having to wait for Oculus, Samsung or Sony to put out finished devices of their own. If you're up to the challenge, you'll find everything you need at the source link.

[Image credit: Noe Ruiz]

Filed under: Displays, Wearables

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Source: Adafruit

In honor of DEFCON, this week we’re looking at some cryptography and reverse engineering projects over at Hackaday.io

Every hacker loves a hardware puzzle, and [Tom] has created a tool to make those puzzles. His Hardware Reverse Engineering Learning Platform consists of a shield with two ATmega328 chips and an I2C EEPROM. The two Atmel chips share a data bus and I2C lines. Right in the middle of all this is an ST Morpho connector, which allows an ST Nucleo board to act as a sniffer. The platform allows anyone to create a reverse engineering challenge!

To successfully reverse engineer a board, it sure helps to have good tools. [coflynn] is giving that to us in spaces with The ChipWhisperer. ChipWhisperer is an open source security research platform. The heart of the system is a Xilinx Spartan 6 FPGA. The FPGA allows very high speed operations for things like VCC and clock glitching. ChipWhisperer is an entire ecosystem of boards – from LNA blocks to field probes. The entire system is controlled from an easy to use GUI. The end result is a powerful tool for hardware attacks.

On the Encryption side of the house, we start by keeping the Feds at bay. The [Sector67] hackerspace has collectively created NSA AWAY. NSA AWAY is a simple method of sending secure messages over an insecure medium – such as email. A one-time use pad is stored on two SD cards, which are used by two Android devices. The message sender uses an Android device to encrypt the message. On the receive side, the message can be decoded simply by pointing an android device’s camera at the encrypted data. So easy, even a grandparent could do it!

Next up is [Josh's] Bury it under the noise floor. “Bury it” is an education for cryptography in general, and stenographic software in particular. [Josh] explains how to use AES-256 encryption, password hashing, and other common techniques. He then introduces stenography  by showing how to hide an encrypted message inside an image. Anyone who participated in Hackaday’s ARG build up to The Hackaday Prize will recognize this technique.

[yago] gives us encrypted voice communications with his ZRTP Hardphone. The hardphone implements the ZRTP, a protocol for encrypted voice over IP communications. The protocol is implemented by a Raspberry Pi using a couple of USB sound cards. User interface is a 16×2 Line character LCD, a membrane keypad, and of course a phone handset. Don’t forget that you need to build two units,or  whoever you’re trying to call will  be rather confused!

Finally we have the Mooltipass. Developed right here on Hackaday by [Mathieu Stephan] and the community at large, Mooltipass is a secure password storage system. All your passwords can be stored fully AES-256 encrypted, with a Smart Card key. Under the hood, Mooltipass uses an Arduino compatible ATmega32U4 microcontroller. UI is through a OLED screen and touch controls.

That’s it for this week! Be sure to check out next week’s Hacklet, when we bring you more of the best from Hackaday.io!

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A few years ago, the most common method to put an Arduino project on the web was to add a small router loaded up with OpenWrt, wire up a serial connection, and use this router as a bridge to the Internet. This odd arrangement was possibly because the existing Arduino Ethernet and WiFi shields were too expensive or not capable enough, but either way the Arduino crew took notice and released the Arduino Yun: an Arduino with an SoC running Linux with an Ethernet port. It’s pretty much the same thing as an Arduino wired up to a router, with the added bonus of having tons of libraries available.

Since the Yun is basically a SoC grafted onto an Arduino, we’re surprised we haven’t seen something like this before. It’s an Arduino shield that adds a Linux SoC, WiFi, Ethernet, and USB Host to any Arduino board from the Uno, to the Duemilanove and Mega. It is basically identical to the Arduino Yun, and like the Yun it’s completely open for anyone to remix, share, and reuse.

The Yun shield found on the Dragino website features a small SoC running OpenWrt, separated from the rest of the Arduino board with a serial connection. The Linux side of the stack features a 400MHz AR9331 (the same processor as the Yun), 16 MB of Flash, and 64 MB of RAM for running a built-in web server and sending all the sensor data an Arduino can gather up to the cloud (Yun, by the way, means cloud).

All the hardware files are available on the Yun shield repo, with the Dragino HE module being the most difficult part to source.

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