Acoustic Wayfinder for the Visually Impaired

Ideally, technology is supposed to enhance our lives. [Shane and Eileen], two seniors at Cornell have found a great way to enhance the lives of visually impaired individuals with their acoustic wayfinding device. In brainstorming for their final project, [Shane and Eileen] were inspired by this Hackaday post about robots as viable replacements for guide dogs. They sought to provide wearable, hands-free guidance and detection of (primarily) indoor obstacles—namely chairs, benches, and other inanimate objects below eye level.

The wayfinder comprises two systems working in tandem: a head-mounted navigation unit and a tactile sensor worn on the user’s finger. Both systems use Maxbotix LV-MaxSonar-EZ0 ultrasonic rangefinder modules to detect obstacles and vibrating mini-disc motors to provide haptic feedback at speeds proportionate to the user’s distance from an obstacle.

The head unit uses two rangefinders and two vibrating motors. Together, the rangefinders have a field of view of about 120 degrees and are capable of detecting obstacles up to 6.45 meters away. The tactile sensor comprises one rangefinder and motor and is used in a manner similar to a Hoover cane. The user sweeps their hand to detect objects that would likely be out of the range of the head unit. Both parts are ergonomic and  size-adjustable.

At power up, [Shane and Eileen]‘s software performs a calibration of the tactile sensor to determine the distance threshold in conjunction with the user’s height. They’ve used an ATMega 1284 to drive the system, and handled real-time task scheduling between the two subsystems with the TinyRealTime kernel. A full demonstration video is embedded after the break.

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LED Matrix Mask Will Scare Up Holiday Cheer

[Davide] sent us this fun LED matrix mask he built using an ATMega8 and 74LS595N shift registers. Each of the eyes is an 8×8 LED matrix, and the mouth is made from two 8x8s. [Davide] used a ULN2803A Darlington transistor array to drive the matrices.

When the user steps behind the mask, an IR sensor detects that a face is within range and activates the facial features. The code randomly runs the eye and mouth patterns. If the user starts speaking, a microphone element detects his voice and a separate speaking mouth pattern is executed.

The mask body and stand are découpaged with pages from Dylan Dog comics. [Davide] says he built the mask years ago, but decided to submit it to the 2013 Inverart Art Fair in Milan. As you can probably imagine, the mask has been a big hit with the kids so far. Stick around to see [Davide]‘s Santa-fied demonstration after the jump. [Davide] didn’t give us any details on that sweet hat, unfortunately.

If you require a better degree of protection or more LEDs, check out this LED helmet.

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IR Theremin Speaks In Four Voices


At the end of every semester, we get a bunch of cool and well-documented student projects from Cornell’s ECE4760 class. [Scott] and [Alex]‘s infrared theremin is no exception.

The classic theremin design employs each of the player’s hands as the grounded plate of a variable capacitor in an LC circuit. For the pitch antenna, this circuit is part of the oscillator. For the volume antenna, the hand capacitor detunes another oscillator, changing the attenuation in the amplifier.

[Scott] and [Alex] put a twist on the theremin by using two IR sensors to control volume and pitch. The sensors compute the location of each hand and output a voltage inversely proportional to its distance from the hand. An ATMega1284P converts the signal to an 8-bit binary number for processing. They built four voices into it that are accessible through the push-button switch. The different voices are created with wave combinations and modulation effects. In addition to Classic Theremin, you can play in pure sine, sawtooth, and FM modulation.

If you’re just not that into microcontrollers, you could build this digital IR theremin instead. If you find IR theremins soulless or plebeian, try this theremincello.

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Automated Drink Mixer Is the Life of the Party

Hosting a New Year’s Eve party, but don’t want to be stuck behind the bar all night? You could set out a bowl or two of spiked punch, but where’s the hack? Free yourself from drink slinging duties with the Automated Drink Mixer created by Cornell University students [Justin] and [Austin]. Their design uses a 14″ diameter lazy Susan powered by a 12V bi-directional motor attached to a 2″ rubber wheel. The motor is capable of 70RPM, so the glass ultimately rides around at 10RPM. Orders are entered on a push-button menu. As this is a school project that should adhere to IEEE standards, all libations are non-alcoholic.

The software uses an overarching state machine, so the system polls for input from the menu at idle. When it receives an order, the lazy Susan rotates the glass to the right spout or series of spouts and then returns it to the starting point. [Justin] and [Austin] controlled the position of the glass with an IR emitter and phototransistor. This pair detects the black strips of tape around the edge which are spaced 60° apart. A comparator digitizes the signal and triggers an interrupt in the software, which counts the number of 60° slices. A full demonstration is waiting for you after the jump. Before you jump: drink responsibly, kids. If you aren’t up to that particular challenge, make yourself an alcohol-aware LED ice cube. If you need more LEDs in your life, whip up the Inebriator.

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Touching Conversations: Email Snippets Scroll By on Electro-Embroidery Piece


[Wei Chieh Shih] really moves the needle when it comes to wearable technology. His textile design project entitled I Am Very Happy I Hope You Are Too is a striking marriage of masterful hand embroidery, delicate circuitry, and careful programming.

[Wei] is using an Arduino micro to drive a matrix of surface-mount LEDs in the Hello, World video, which is a ramp-up to the scrolling text version that’s in progress now finished. That full version is part of his residency project at Arquetopia in Oaxaca, Mexico and displays snippets of emails from his past relationships. It’s huge, with multiple matrices as large as 8×25 pixels!

No build notes could be found for this or any of [Wei]‘s similar projects, like this awesomely dangerous 200 laser diode jacket or this eerily beautiful light installation on Taiwan’s north beach. Based on the pictures, our speculation is that he is using ordinary 6-strand embroidery floss to make stem or half cross-stitches on all the paths. He then runs very thin, flexible conductor underneath the channel of stitches and solders the wires to the component pads.

If [Wei] wants another way to wear his heart on his sleeve, he could investigate these dynamic LED clothing hacks.

Update: [Wei] has completed this project, and has more information available at his Behance site.

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New Contest: Win One of 20 Microchip Fubarino SD Boards


We had a blast with the Trinket Contest in October and November and can’t wait to see what you can come up with for this month’s competition. Microchip Technology is one of our advertisers and they offered us 20 Fubarino SD boards to give away as prizes. The challenge for you is to add our URL as an Easter Egg in your own microcontroller project. Rise to the top of our seemingly arbitrary system for picking winners and one will be delivered to your door for your future hacking pleasure.

Obviously we mean when we say URL, but what constitutes an Easter Egg? We figure it’s anything that is not apparently obvious in a piece of hardware. We built a quick example to get you thinking. Shown off in the clip after the break is a clock that displays our web address every day at 1:37pm. What did we pick that time? Because our clock displays in 24-hour time format and 13:37 is leet. See the code we used in our repo.

We thought of a few others, like making an embedded gaming that uses the Konami Code to reveal the Easter Egg, or a man-in-the-middle device that attaches to your keyboard and redirects your feeble attempts to load Facebook by closing the tab and opening Hackaday. The sky’s the limit with how creative these things can be!

Follow these rules to submit your qualifying entry:

  • You must somehow hide in your microcontroller project (embedded Linux doesn’t count unless you do some type of bare-metal programming)
  • Preference will be given to projects that are both clever and well documented. Notice we made a video, and posted code and an explanation of our project.
  • Write an email that has “[Fubarino]” in the title, includes the information on your documented entry, and lists your name and mailing address. Your name and mailing address will be used for shipping only and NOT for anything else. Emails should be sent to:
  • Entries must be received before 12:00am Pacific time on 12/19/2013.
  • Employees and their families of Hackaday, SupplyFrame, and Microchip Technology are not eligible to win.

What are you waiting for? Dust off those chips and get hacking!

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Turbot is a Beam/Picaxe Hybrid


[James] wanted to build a BEAM turbot. He ran into some problems with the BEAM circuitry though, and ended up with a BEAM/Picaxe hybrid.
Beam robotics are the brainchild of Mark Tilden. The acronym stands for Biology, Electronics, Aesthetics, and Mechanics. BEAM based bots were very popular with hobbyists in the 90’s and early 2000’s, but popularity has since died down. BEAM robots tend not to use microcontrollers, instead attempting to simplify things down to the lowest number of elements.

[James’] turbot uses a miller solar engine. The original design used the engine to drive a Solar Turbot Latch. [James’] problem was that the photodiode “eyes” of the robot were not properly enabling the 74AC245 to pass current to the motor. Since the robot was built in a tiny space, debugging the circuit was extremely hard. After struggling with the ‘245 for some time, [James] decided to swich out the BEAM circuit for a Picaxe microcontroller.

The Picaxe can only sink or source about 20ma per pin, which is slightly less than the no load current of [James’] motors. To make up for this, he ganged up four pins per motor. There was some risk in the motors blowing up the Picaxe. However between the lightly loaded gearmotors and low current solar panels it seems to be working just fine.  Overall the bot is a very clean, compact build. Jump past the break to check out its really smooth crablike walking action.

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