Thursday, October 9, 2008
Removable Flash Memory Cards
While your computer's BIOS chip is the most common form of Flash memory, removable solid-state storage devices are becoming increasingly popular. SmartMedia and CompactFlash cards are both well-known, especially as "electronic film" for digital cameras. Other removable Flash memory products include Sony's Memory Stick, PCMCIA memory cards, and memory cards for video game systems such as Nintendo's N64, Sega's Dreamcast and Sony's PlayStation. We will focus on SmartMedia and CompactFlash, but the essential idea is the same for all of these products. Every one of them is simply a form of Flash memory.
There are several reasons to use Flash memory instead of a hard disk:
* Flash memory is noiseless.
* It allows faster access.
* It is smaller in size.
* It is lighter.
* It has no moving parts.
So why don't we just use Flash memory for everything? Because the cost per megabyte for a hard disk is drastically cheaper, and the capacity is substantially more.
smart media flash card
The solid-state floppy-disk card (SSFDC), better known as SmartMedia, was originally developed by Toshiba.
SmartMedia cards are available in capacities ranging from 2 MB to 128 MB. The card itself is quite small, approximately 45 mm long, 37 mm wide and less than 1 mm thick. This is amazing when you consider what is packed into such a tiny package!
As shown below, SmartMedia cards are elegant in their simplicity. A plane electrode is connected to the Flash-memory chip by bonding wires. The Flash-memory chip, plane electrode and bonding wires are embedded in a resin using a technique called over-molded thin package (OMTP). This allows everything to be integrated into a single package without the need for soldering.
diagram of smart media card
The OMTP module is glued to a base card to create the actual card. Power and data is carried by the electrode to the Flash-memory chip when the card is inserted into a device. A notched corner indicates the power requirements of the SmartMedia card. Looking at the card with the electrode facing up, if the notch is on the left side, the card needs 5 volts. If the notch is on the right side, it requires 3.3 volts.
SmartMedia cards erase, write and read memory in small blocks (256- or 512-byte increments). This approach means that they are capable of fast, reliable performance while allowing you to specify which data you wish to keep. They are small, lightweight and easy to use. They are less rugged than other forms of removable solid-state storage, so you should be very careful when handling and storing them.
CompactFlash cards were developed by Sandisk in 1994, and they are different from SmartMedia cards in two important ways:
* They are thicker.
* They utilize a controller chip.
CompactFlash consists of a small circuit board with Flash-memory chips and a dedicated controller chip, all encased in a rugged shell that is several times thicker than a SmartMedia card.
As shown below, CompactFlash cards are 43 mm wide and 36 mm long, and come in two thicknesses: Type I cards are 3.3 mm thick, and Type II cards are 5.5 mm thick.
Compact Flash card
CompactFlash cards support dual voltage and will operate at either 3.3 volts or 5 volts.
The increased thickness of the card allows for greater storage capacity than SmartMedia cards. CompactFlash sizes range from 8 MB to 6GB. The onboard controller can increase performance, particularly on devices that have slow processors. The case and controller chip add size, weight and complexity to the CompactFlash card when compared to the SmartMedia card.
Sunday, October 5, 2008
The technology developed by Marine Current Turbines Ltd works much like submerged windmills, but driven by flowing water rather than air. They can be installed in the sea at places with high tidal current velocities, or in places with fast enough continuous ocean currents, to take out copious quantities of energy from these huge volumes of flowing water.
The technology being deployed by MCT, known as “SeaGen” consists of twin axial flow rotors of 15m to 20m in diameter (the size depending on local site conditions), each driving a generator via a gearbox much like a hydro-electric turbine or a wind turbine. These turbines have a patented feature by which the rotor blades can be pitched through 180o in order to allow them to operate in bi-direction flows – that is on both the ebb and the flood tides. The twin power units of each system are mounted on wing-like extensions either side of a tubular steel monopile some 3m in diameter and the complete wing with its power units can be raised above sealevel to permit safe and reliable maintenance.
SeaGen in Strangford Lough
Saturday, September 27, 2008
Konarka’s patented PowerPlastic® is a thin, lightweight, and very flexible material that will serve as an integrated low-cost source of power for portable devices, on and off-grid systems, and for structures. Konarka has developed proprietary semi-conductor organic polymers that exhibit:
- low cost,
- abundant supply, and
- low toxicity
PowerPlastic® has distinct advantages relative to conventional PV technology.
|Low Light Performance||Higher efficiencies at moderate and low light levels.|
|Flexibility||Can be flexed to a 2-in diameter, making it more conformable for product integration.|
|Broader Spectrum||The combination of polymers is able to absorb a broader portion of the light spectrum.|
|Positive Thermal Co-efficient||Cell efficiency increases with temperature, whereas rising temperatures degrade the performance of other technologies.|
|Abundant Material Supply||The raw materials are not limited by the availability of silicon.|
Beyond these key differentiators, its potential for further unique attributes, such as transparency and the ability to print camouflage and other patterns, have attracted the attention, imagination, and investment of several branches of the US military, the National Science Foundation, DARPA, the Department of Energy, the Department of Commerce, Fortune 100 companies, and leading venture capital firms.