Thursday, December 27, 2012

Fingertip Tingle Enhances Surgeon's Sense of Touch

Our fingers are precision instruments, but there are plenty of things they are not sensitive enough to detect. Now we can augment their talents - using wearable electronics at fingertips that provide tingling feedback about whatever we touch. 
Nanotechnology in figertips

Scientists have designed a flexible circuit that can be worn over the fingertips. It contains a layer of gold electrodes just a few hundred nanometres thick, sandwiched between the layers of polymide plastic to form a "nanomembrane". This is mounted on a finger shaped tube of Silicon rubber, allowing one side of the circuit to be in direct contact with the fingertips. On the other side sensors can be added to measure temperature, pressure or other electrical parameters such as resistance. 

People wearing this device receive a electrotactile simulation -  a tingling sensation caused by a small voltage applied to the skin. The size of the voltage is controlled by the sensor and varies depending on the properties of object being touched.

Human Ear As A Battery

Inner ear's energy can work like a battery, can power tiny devices .

For the first time, an electrical device has been powered by the ear alone. The team behind he technology used a natural electrochemical gradient in cells with the inner ear of a guinea pig to power a wireless transmitter for u to five hours. The technique could one day provide an autonomous power source to the brain and cochlear implants, says Tina Stankovic, an auditory neuroscientist at Harvard University Medical School in Boston, Massachusetts. 
Cochlear cells from mammalian inner ear
Nerve cells use the movement of positively charged sodium and potassium ion across a membrane to create an electrochemical gradient that drives neural signals. SOme cells in the cochlear have the same kind of gradient, which is used to convert the mechanical force of the vibrating eardrum into electrical signals that brain can understand.

Tiny Voltage

A major challenge in tapping such electrical potential is that the voltage created is tiny – a fraction of that generated by a standard AA battery. Now, Stankovic and her colleagues have developed an electronic chip containing several tiny, low resistance electrodes that can harness a small amount of this electrical activity without damaging hearing. The implant was inserted into a guinea pig's inner ear and the electrodes attached to both sides of cochlear cell membranes. Attached to the chip was a low power radio transmitter.

Guinea Pig

The device needed kick-starting with a short burst of radio waves, but was then able to use the electrical gradient running across the membrane to sustain the transmitter for up to five hours. Tests showed that the guinea pig's hearing was not affected.The device works well for short durations but long-term use of the electrodes risks damaging the sensitive tissue inside the ear. The next step will be to make the electrodes even smaller, reducing their invasiveness.

Monday, December 24, 2012

How 3D Glasses Work

As the cinematic experience radically changed from  Black & White to colour and the current 3D/4D/6D, so did the TVs n our home. 3D glasses are indispensable to enjoying 3D effect.


3D effect relies on creating an illusion of depth to the viewer. To understand what this means, watch your thumb with both your eyes, then close one eye while you keep watching with other one. Now close this eye and open the other one. Repeat this twice or thrice.You will se as if thumb is shifting back and forth. This back and forth distance basically arises due to the depth created in the visualising the thumb with different eyes.
Working of Red/Blue 3D glass
This simple phenomenon is the basis for developing 3D glasses. The movie screen actually displays two images. The glasses are designed to feed different images into our eyes. These let one of the images to enter one eye and the other to enter the other eye. This is achieved by either of two ways red/green or red/blue , and polarisation.

Red/Green or Red/Blue 3D glasses

In this system to produce the 3D effect, two images are displayed on the screen- one in red and the other in the green or blue. The colour filters on the glasses allow only one image to enter each eye. This leads depth to the image,making it appear 3D to our brain.  However image quality with this system is not as good as the polarised system. The reason is it somehow restricts some of the actual colours of the scene as it applies filtration y means of the colour itself.


This method uses differently polarised lenses to feed images into our eyes. The system consists of two synchronised projectors to project two respective view of an image, each with a different polarisation  The glasses have a pair of differently polarised filters at 90 degrees to each other  As each filters passes only that light which is similarly polarised and blocks the light polarised in the opposite direction, each eyes sees a different image. Thus two different images reach our eyes, creating a sense of  depth leading to a very high quality 3D effect.

Future Smart Phones

Future Smart Phones could be as thin as a Credit Card

Scientists are working on a new ultra thin lens that could lead to smartphones as thin as a credit card in the coming years. The new distortion free is said to be so small that more that 1500 would fit across the width of the human hair. In the near future, it is likely t replace lenses in the applications ranging from mobile phones to cameras to fibre-optic communication systems.

Ultra thin lens can lead to smartphones as thin as
credit card
Existing lens are neither thin nor flat enough to remove distortions such as spherical aberration. It is possible to correct these distortions but only through complex solutions such as multiple lens that increases the weight and take up the space.This is the reason that Scientists started working on a new super thin, flat lens to address these issues.

Despite being ultra thin, the new lens features a resolving power that is said to approach the theoretical limits set by the laws of optics. The lens surface is patterned with tiny metallic stripes which bend light differently as one moves away from the centre, causing beam to focus sharply without distorting the images.The current version of lens works at design wavelength, but the scientists say it can be redesigned for se with broadband light.

Sunday, December 23, 2012

3D Chips - The Future of Electronics

                The 3D ICs are believed to be best way to keep Moore's Law ticking.

On an average , a chip holds over one billion transistors today. Intel's 10-core Xeon Westmetre-EX packs 2.6 billion transistors into a 512 mm2  using 32 nm technology. The thirst for more features and processing power is unquenchable, but how much more can you pack into a chip? If transistors get any smaller, their reliability could become questionable. Plus,  if you need to make the chip denser, the fabrication costs might also become unreasonably high.  Such issues have led to the development of 3D IC technology, wherein two or more dice are stacked atop of each other.

Benefits of 3D chips :

3D IC stacking

1. 3D chips saves space. Dice that used to be centimetres apart on a chip can now be placed millimetres apart, and that too vertically.

2. Since the dice are close by, the interconnect length is significantly smaller. This results in low latency and high performance.

3. Stacking helps overcome the memory-to-processor performance bottleneck that plagues 2D ICs.

4. 3D interconnects permit data to be moved both horizontally and vertically. This helps boost performance 
by 30 to 40percent.

5. Bandwidth is much higher as it is possible to have a large number of vertical vias between the layer.

6. 3D chips consumes 30 to 40 percent less power than traditional ICs.

7. 3D stacking permits heterogeneity, since the dice arranged one above the other need not be similar.

Techniques for stacing the dice in a 3D chip:

There are several ways to stack the chips, Gilies Peckham, EMEA director-Marketing, Xilinx, explains ost common ones:

1. Connecting two stacked chips to a flip chip at the bottom of the stack. Examples are SoCs where a dynamic Random Access memory (DRAM) is placed on top of the Central Processing unit (CPU).

Xilinx Stacked Silicon Interconnect technology

2. Using TSV, where the dice are place on the top each other and connected through vertical copper channels. An example of TSV usage is the super-density DRAMs used in camera CMOS sensors.

3. Making use of silicon transposer, which connects two or more chips together - much like transposers used in AMD graphics cards. 

Device That Can Convert Images Into Music

The Eye-music - a device that converts images into music. The Pleasant musical tones ans scales produced to help individuals without vision 'see' using music.

Eye music SSD,showing a user with a camera mounted on the
glasses, and headphones, hearing musical notes that create a mental
image of visual scene in front of him. 

Once an image is scanned, it represents pixels at high vertical location as pitched musical notes and low-vertical location as low pitched notes. The image is scanned continuously from left to right, and an auditory cue is used to mark the start of the scan. The horizontal location of the pixel is indicated by the timing of the musical notes relative to te cue and brightness is encoded by the loudness of the sound.

"Eye Music" which employs pleasant musical scales to convey visual information, can be used after a short training period to guide the movements visually.

Technology That Turns Paper Into Digital Display

At University of Tokyo, the Naemura Group is developing  a paper computing technology that lets users draw,edit and erase sketches on the paper by using computer. Here's how it works. The pen is filled with a thermo-sensitive ink, which disappears when heated at certain temperature. If you want to erase or edit your work, the computer uses a super-precise laser to heat the specific areas of your drawing that you get rid of.

The paper is coated in a light sensitive photochromic solution, which makes it change colour when exposed to UV light. Above the workstation, a UV projector can draw on the paper using targeted rays.

According to engineers, this technology can directly turn a paper into display. Until now, it has been possible to project things onto paper and use it as a screen, or import things drawn on the paper to a PC by using a digital pen. But the first method uses a light, so he results can be seen only in the dark. With the second method, even if you can import things, you can't access them on the paper from computer.