Math Monday: Hula Hoop Geometry, Part 1

By Glen Whitney for the Museum of Mathematics


Math Mondays have so far featured a wide array of different items from which one can make a tremendous variety of geometric constructions, but there has not yet been one on hula hoops. This week and next we’ll remedy that oversight. Also, the postings so far have almost entirely shown the constructions as fait accompli, so this series will also try to give a bit of insight into the process of devising a new creation.

Total structural collapse, leading to hula chaos! What to do?

To be continued…

See all of our Math Monday columns


Aquabotix: Remote controlled underwater eye


This compact remote controlled underwater vehicle can record live video and capture photos in HD, streaming them to your iPad and allowing you to share with family and friends. The vehicle’s features includes LED lights, HD camera, Standard 75 foot cable, Waterproof carrying case, Topside box which produces vehicles Wi-Fi. This underwater bot is perfect for studying marine life, checking water depths or inspecting under your boat. Stay dry and safe from topside while recording videos and snapping photos to upload and share on social media sites.

The HydroView remotely controlled underwater vehicle lets you check on an anchor, look for something that fell overboard or off a dock and study marine life

MoleBot: Mole in a Table

MoleBot is a mole robot built under a transformable board table that allows people to interact with everyday objects and props, and experience what it feels like to have a mole live under your table. MoleBot gives us the feeling as if the interactive interface blends the virtual and the physical reality.

It was exhibited at SIGGRAPH 2011 Emerging Technologies from August 7 to 11 in Vancouver, Canada. The MoleBot project was invited at Laval Virtual 2012 and won the Laval Virtual Awards grand prix on March 29, 2012.

The Pipe Crawler

images taken from:

Eiki Martinson published a really cool senior university project, where he and his team implemented a Pipe Crawler robot. Pipe inspection definitely is one of those specialized killer apps of robotics, like exploring space, recently search and rescue within radioactive facilities or mowing the lawn, that have spawned a remarkable number of experimental attempts, working machines for industry, and even (in the case of mowing the lawn) consumer products. Examples of pipe-crawling robots pop up every couple of months in the popular scientific magazines. To distinguish their approch from other already existing efforts, they decided that the machine should be able to travel through horizontal segments, around corners, and straight up. This last requirement rules out a simple rover or wheeled cart. To maintain itself in a vertical section, the robot has to press wheels against the sides of the pipe by mechanical means (ruling out serpentine or inchworm mechanisms—but these also have to press something at least against the walls). They selected a radial arrangement of three sprung wheels. The robot would consist of many such units, articulated like a railroad train, so that it could negotiate corners.

A really nice work, despite the fact that it was finished in 2003. The online documentation of the work is really good and worth reading.

Analyzing and Classifying Personality Traits with Smartphones

Gokul Chittaranjan and his team, including members from Nokia, published an interesting work which introduces the investigation of the relationship between behavioral characteristics derived from rich smartphone data and self-reported personality traits. They used data stems from smartphones of a set of 83 individuals collected over a continuous period of 8 months. The analysis showed that aggregated features obtained from smartphone usage data can be indicators of the Big-Five personality traits. They also developed an automatic method to infer the personality type of a user based on cellphone usage using supervised learning. Surprisingly, their method performs signi cantly above chance and up to 75.9% accuracy.
This seems to be one of the first studies that analysis and classifies the personality characteristics by using smartphone data!

And they won the Pervasive2011 conference best paper award, congratulation guys!

Special Issue: LED-Throwies

Its time for a special issue about LED-Throwies, because i like this simple and illuminated concept so much! A LED-Throwie is a LED mounted on a coin cell battery in combination with some sort of a glueing material, such as a magnet for throwing it on metal. LED-Throwies were invented by the Graffiti Research Lab (GRL), as a destruction free variant of a lightning graphity. LED-Throwies are used mainly for street art or as light effects for events. There are no limitations for endless applications on public statues, buildings, bridges or transport.

Payments And Online ID Verification Company Jumio gathered investment From Citi Ventures

jumio-logoThe mobile and online payments and ID verification startup Jumio got an additional investment by Citi Ventures, a unit of global financial services company Citi. This is another funding that followed Jumio’s $25.5 million from March, led by Andreessen Horowitz. Although Citi’s investment amount is not being disclosed, to date, Jumio has raised $35.4 million in funding.

Daniel Mattes, the founder of Jumio, is building an online and mobile ID and payment platform which should make it easier and safer to pay online with your credit card. Mattes also founded and successfully sold his first VoIP company Jajah for more that 200 Mio $ to  Telefonica, which is quite a bit 😉

Fabric Jacketed Power Cords

Apparently there’s a retro vogue going on in the design world when it comes to appliance, lamp, and power cords. Shown here, a selection of colorful braided fabric cable looms available from Sweden’s FRINAB Fristad Industri Aktiebolag. The cable is available in small quantities, online through their NUD Collection brand, which includes a webshop that will sell you either mix-and-match custom lamp cordsets or just the cable. They have 44 different colors and / or patterns; the 10 foot length costs $14, and the longer, 20-foot length actually costs more, on a per-foot basis, at $35.

They’ll send you free samples, too, in the colors of your choice. Shown here is a scan of the card they just sent me, with two three-inch whole cable samples on the left and two loom-only samples on the right. [via adafruit]

NUD Collection

Kickstarter’s $8 Million Pebble watch

Watch the interview with Eric Migicovsky, who is the creator of the Pebble Bluetooth watch, a Kickstarter project that’s raised over $8 million.
Pebble Founder Eric Migicovsky, the 25-year behind the 8 million dollar Kickstarter campaign, the largest ever. According to Eric, Pebble is the watch of the 21st century, allowing it to connect to your iPhone as well as download different apps and watch interfaces. Eric talked with Shira about how Kickstarter gave them an opportunity, making something people want and how awesome the Pebble watch is.