Author Archive

Artificial Gecko Feet Has Arrived

November 21st, 2014 No comments

Scientists discovered a number of years ago that the modest gecko makes use of a fascinating trick of physics to remain stuck to surfaces. A gecko’s foot is covered in ridges that exploit van der Waals forces to adhere to anything that’s sufficiently smooth. Now researchers at Stanford working with the US Defense Advanced Research Projects Agency (DARPA) have created a functional human-scale version of the gecko’s foot. Just strap these pads to your hands, and get climbing… slowly.


Physicists have known about the van der Waals force for decades, but its effects are rarely seen beyond the microscopic scale. The van der Waals force is simply an attractive force between two molecules that is not due to covalent or ionic bonding (i.e. molecule forming). It has to do with the way electrons are shared within molecules. As these negative particles shift around in the cloud surrounding a positively charged nucleus, they can occasionally cluster on one side, which gives the molecule a temporary charge differential or “dipole.” Other molecules have a permanent dipole, but the effect is the same–there’s a weak attraction between them.

The hand-sized pads designed by Stanford and DARPA are operating entirely on van der Waals force, just like a gecko There are 24 small panels on each pad the size of a postage stamp, which are arranged in slanted rows. None of the panels would feel particularly sticky if you were to touch them, but pressing the pad to a glass surface and pulling down makes it instantly stick. The large surface area of the pads ensures that it remains in place until the user lifts it. Unlike past attempts, researchers believe this design can be used for long periods of time, not just for short demos.

On a microscopic level, this silicone material works much like a real gecko’s feet. A gecko has ridges called setae on its feet, each of which is covered in microscopic hair-like projections called spatulae. This gives the gecko’s foot a much larger effective surface area than you’d think just looking at it. The artificial material developed by researchers is similar, made from a type of silicon material called polydimethylsiloxane. Each of the 24 pads is covered with microscopic slanted wedges that increase effective surface area. Arranging the gripping surface into separate pads helps the device cling to irregularities in the surface, but it still requires a mostly smooth surface to work.


Even before developing this material, researchers knew sticky gloves wouldn’t be good enough. One problem with the “Spider-Man” model of climbing walls is that most people have considerably more strength in their legs than their arms. That makes the climbing gloves insufficient to scale walls no matter how well they stick. To get around this, the researchers have attached a series of cables to each hand pad that transfers the load to the feet. There’s a rigid platform for each foot to rest on, so the climber can shift their weight back and forth, re-positioning one pad at a time then stepping up onto the now higher platform.

You can see this method at work in the video above, and it isn’t much more strenuous than climbing a ladder. However, it’s pretty slow–the video is sped up by 2 times. The team hopes future designs will make the gecko climbing system easier and faster. There’s also still work to do optimizing the micro-wedge material for less smooth surfaces and finding a way to keep it clean. This is still a big achievement as the first technology that can support a human climber using van der Waals forces.

— From

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Charging a dead Nexus 7

September 30th, 2014 No comments

I have a nexus 7 tablet that had been “dead” a few times.  Each time it gets into the dead mode, the back light flash about once per second when I was trying to power it on.  When charging, the charge icon will not come on, and the tablet can not be powered on even after days of charging.

It appears lots of people ran into similar problems and have various fixes described on the web. One is fixing the loose battery connector.  It did not work for my tablet.  Only the following approach fixed my Nexus 7:

1.  Plug-in your dead N7 to a wall charger. (Jump immediately to step 2.)
2.  Immediately after plugging it in, press Volume Down and Power at the same time.

*This should get you into the bootloader menu. You may have to try this with different chargers or test out the timing in order to get it to work.

3.  Once in the bootloader menu, use Volume Down until you see “Power Off Device.”
4.  Choose that option with the Power button.
5.  Once your device is off, unplug the charger and then plug it back into the device.
6.  You should now see the battery meter (pictured above) with your device returning to life.


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Arduino Widely Used in AT&T Car and Home Hackathon

September 15th, 2014 No comments

Last week AT&T’s "Code for Car and Home" hackathon took place at the Cosmopolitan in Las Vegas where over 200 developers, 47 teams, 41 sponsors, and over 300 in total attended. At the hackathon, developers built apps that focused on connected vehicle and home automation. One of our two top winning teams focused on an app to help with distracted driving, phone calls while driving, etc.  Another winner focused on home safety, monitoring and reacting to high levels of carbon monoxide. In total, over $100,000 in prizes were awarded to winning teams.  I was there observing the hackathon and Arduino was widely used in the hackathon projects for sensing and automation.

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Python is the Most Popular Introductory Programming Language at Top US Universities

September 15th, 2014 No comments

Python has surpassed Java and is currently the most popular language for teaching introductory computer science courses at top-ranked U.S. departments. More specifically, eight of the top 10 CS departments (80%), and 27 of the top 39 (69%), teach Python in introductory CS0 or CS1 courses, according to a recent survey posted by ACM  [1]

Python possesses a mix of qualities that makes it a good candidate for universities. It has a simpler syntax than Java or C++, allowing novices to start writing programs almost immediately. At the same time, it can be scaled up for heavy industrial usage — it is widely used in the financial community for data analysis, for instance.

Note this rating is different from what is in the industry. According to TIOBE Programming community index, C and Java are still the top 2 languages on-demand.   However, Top Universities choice of language for their introductory course do influence job market language popularity in the future.



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Eliademy Aims to Help Teachers to Build Online Classrooms

April 24th, 2014 No comments

Eliademy features simple visual tools for creating and editing online courses forums and quizzes, for sharing sharing documents and embedding multimedia content into courses.  It also offers personalizable  educational calendar, news feed, and email notification. Elizademy is built for teachers. With a list of student email, teachers can have them join the LMS enabled by Eliademy.



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CodeAcademy is Moving towards Professional Education

April 24th, 2014 No comments

Since its launch two years ago CodeAcademy has served more than 24million people with its basic computer programming courses.  Now it has decided to move to professional programmer and developer market with more advanced teaching.  For instance, it has redesigned training method that has users build their own iterations of the basic AirBnB site.  They wish the new framework will ultimately connect users to social and career opportunities, to help their students move toward actual careers through the site.

Codecademy said that they are already working with educators around the world to integrate computer programming with basic education provided at secondary schools in the UK, Malaysia, and Singapore.  In the UK, Codecademy has gotten some middle school and high schools to integrate courses into their existing curricula.


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Kimono: a Very Interesting Scraper to APP Concept and Execution

January 17th, 2014 No comments

Kimonolab’s Kimono scraimageper tool is worth to check out if you have any web scraping needs.  It is a visual extractor tool that recognizes patterns in web content and allow you to create cloud hosted scraping tools you want quickly, and you can schedule it to run periodically.  It also has an app builder let you create simple apps based on the generated scraping tools.   

I have written various kind of scraping tools before, this work makes me wonder why I did not go that far. :-)   

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Fast House Prototying/Production using 3D Printing

January 16th, 2014 No comments

The following image explains itself:



Relate report: build a house in 24 hours

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Smartwatch Design Gets Better

January 9th, 2014 No comments

The following are some appealing new designs of smartwatches:

(1) New pebble vs old pebble:

(2) New Meta Smartwatches



(3) Cookoo’s analog timepiece


One attractive point of Cookoo’s watch is its battery life time. Cookoo’s reps boast it’s more than a year.

My major concern about smartwatches includes design, battery life, and pricing.  Happy to see these new designs moving in the right direction. Cookoo’s watch battery life is also nice.  I assume it is largely achieved by its minimal functionality.  Eventually, I would think energy harvesting, maybe combined with remote charging, would be the main way to deal with the unpleasant plug-in-to-charge for watch-like wearable.   Pricing, however, is still a big issue. Ultimately, I believe only when the price goes below $50, the market will really start to open up.  Premium services, not the hardware, are the way to make money in the smartwatch space. 

Parrot Sumo: A Smartphone-Controlled Bot with Plenty of Potential

January 9th, 2014 No comments

Parrot is a French Bluetooth company turned drone-maker. It showed off two brand new smartphone-controlled bots at CES 2014.  One is the rolling, jumping Sumo and the other is the MiniDrone, a super small version of its popular AR Drone that flies, rolls and hugs the Jumping Sumoceiling and the walls.

Piloted via Wi-Fi 2.4 or 5GHz with a Smartphone or a tablet, Parrot Jumping Sumo is a new genre of connected robot. “Half robot, half insect”, it is equipped with a gyroscope and an accelerometer, which provides fool-proof agility and intuitive piloting. It can roll, turn 90 degrees with speed and astonishing precision – meaning no obstacle is too challenging – and also perform spectacular jumps (up to 80 cm) always landing on its “wheels”!  With an embedded camera, its acrobatic and fast-paced movements are streamed onto the screen of the controlling Smartphone or tablet.

There are various video available on the web now (including Parrot’s website) for you to see it in action. 

From what we see so far, I feel it can be a really good robot development hardware platform if Parrot can open it up for the developer community, and I wish they do.

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