Solar Powered LEDs

One of the most practical "no-brainer" new products from CES 2009 was this solar powered LED security light:  

Click through to see a video demo on YouTubeYoutube pic and have excellent selection and value in LED replacement lights.




LED Traffic lightLED Traffic lightLED Traffic light


China – the new horizontal LED traffic light that dynamically changes according to the length of time left on the green or red cycle.  A blinking green one-third-full bar means “reduce speed now”, and a blinking yellow full-bar indicates “proceed with caution”


 Germany:Images-3 UK:Images-1 


Japan:  Images-2 Images-6  Images-8 
 Solar Traffic Light:
Images  Images-7 

Hat top AbsoluteAstronomy!

In most countries, the sequence is green (go), amber (prepare to stop), and red (stop). In some systems, however, just before red changes to green, both red and amber are lit. It is customary for drivers to select neutral and/or use the handbrake at red lights; the additional phase is intended to give the driver time to select first gear or release the handbrake before the light turns green, but in practice is treated as an invitation to go before the green light is showing.

In the UK, New Zealand and Canada, amber officially means ‘stop (unless it would cause an accident to do so)’ but in practice, is treated as ‘prepare to stop’. In Russia and Serbia, the green light flashes for a few seconds before the amber light comes on. The single flashing amber signal is used in the UK, Ireland and Australia at Pelican crossingss. Also it is used in Serbia to mark places where greater attention is needed – dangerous crossings, sharpe curves in road and the like.

Traffic light failure in most jurisdictions must be handled by drivers as a priority-to-the-right intersection in both drive-on-the-left Australia and some states of the mainly drive-on-the-right Europe, or an all-way stop elsewhere, pending the arrival of a police officer to direct traffic.
Some jurisdictions, however, have additional 
right-of-way signs mounted above, below or next to the traffic lights; these take effect when the lights are no longer active. (In Germany and Italy traffic lights inactive at nighttime emit an amber-coloured flashing signal in directions owing priority.) In the UK and North America, drivers simply treat the junction as being uncontrolled when traffic lights fail, giving way as appropriate, unless a police officer is present. In 1999, concerned that some traffic lights would fail as a result of the Y2K bug, some jurisdictions installed emergency unfoldable stop signs at intersections .

In some countries, pedestrian traffic lights include a type of siren, beeper or warbler, which sounds in order to alert visually impaired pedestrians that it is safe to cross. These may be set to a timer and only sound at day time, to avoid annoying residents. Some other intersections include a white strobe light mounted inside the red light that flashes every few seconds when the light is red. (See other comments on red with white strobe later in this article.) Some also include tactile warnings, like a vibrating plate, or a rotating cone, to help deafblind people cross the road and street.

There are significant differences from place to place in how traffic lights are mounted or positioned so that they are visible to drivers. Depending upon the location, traffic lights may be mounted on poles situated on street corners, hung from horizontal poles or wires strung over the roadway, or installed within large horizontal gantries that extend out from the corner and over the right-of-way. In the last case, such poles or gantries often have a lit sign with the name of the cross-street.

Japan and South Korea,along with some jurisdictions in the U.S.Canada, and Mexico mount lights with their multiple faces arranged horizontally, often with supplemental vertical signals on the side, while others use vertical signals almost exclusively. Horizontal signals have consistent orientation, like their vertical counterparts.(*) Often, supplemental curb pedestal mounts, intended to support a signal for a different approach road, are used when primary signals are partially obscured due to structures such as overpasses, approaches around a building that obscures the primary signal mountings, and unusual approach geometry. In Florida, horizontal signals mounted on poles, known as “mast arms”, are in wide use due to their lower wind profile, important for minimising hurricane damage.
California, where I now live, particularly fastidious in ensuring that drivers can see the current state of a traffic light. One entrance to a typical large intersection, with three through lanes, two dedicated left-turn lanes, and a crosswalk, may have as many as three traffic lights for the left-turn lanes, three for the through lanes, and a pedestrian signal for the crosswalk. And those numbers must be multiplied by four to cover all four ways to enter a typical intersection.

In addition to being positioned and mounted for desired visibility for their respective traffic, some traffic lights are also aimed, louvered, or shaded to minimise mis-interpretation from other lanes. For example, a Fresnel lens on an adjacent through-lane signal may be aimed to prevent left-turning traffic from anticipating its own green arrow. One fresnel example common in the USA is known as a 3M “Program Head”, although 3M has recently discontinued the line. Shades and back panels are also useful in areas where sunlight would diminish the contrast and visibility of a signal face. 

Traffic signals in most areas of Europe are located at the stop line on same side of the intersection as the approaching traffic and are often mounted overhead as well as on the right and left sides of the road. The stop line alignment is done to prevent crosswalk blocking and allow for better pedestrian traffic flow. In
North America, there is often a pole-mounted signal on the same side of the intersection, but additional pole-mounted and overhead signals are usually mounted on the far side of the intersection for better visibility. In some areas, signals facing all four directions are hung directly over the intersection on a wire strung diagonally over the intersection.

In Canada, an unusual jurisdictional arrangement can be found: motorists proceeding east at the intersection situated on the border must, while in Alberta, stop for a red signal located in Saskatchewan; the reverse applies for westbound motorists. If such a motorist were to disregard the signal and collide with a vehicle proceeding from that motorist’s left, the collision would occur in a province other than the one where the traffic control device is located.



An experiment with low-cost, solar-powered light emitting diode (LED) lamps that is lighting up the lives of a handful of families in rural India could become a beacon of hope for millions of poor people worldwide who currently rely on kerosene lamps and other lighting solutions that are toxic–and frequently lethal–when used indoors.

Solar Lighting Eliminates the Need for Electricity in Rural Areas
The Grameen Surya Bijli Foundation (GSBF), a Bombay-based nongovernmental organization that is committed to bringing light to rural India, installed the $55 lamps in about 300 homes. About 100,000 villages in India still do not have electricity, and the cost of lighting those villages by traditional means is prohibitive. The solar LED technology eliminates the need for electric lights. After the initial cost, solar energy continues to light the lamps free of charge.

“Children can now study at night, elders can manage their chores better,” one relieved villager told The Christian Science Monitor. “Life doesn’t halt anymore when darkness falls.”

LED Lamps Provide Safer and Better Light For Less
Replacing kerosene lamps with clean solar-powered LED lamps also provides healthier and safer living conditions as well as better light for less money. According to The Christian Science Monitor, about 1.5 billion people worldwide use kerosene to light their homes, but the fuel is dangerous.

Separate reports by the Intermediate Technology Development Group and the World Health Organization indicate that indoor air pollution from kerosene and similar fuels used for indoor lighting and cooking cause more than 1.5 million deaths annually. The risk of fire is another significant health hazard with kerosene lamps.

Kerosene Expensive and Dangerous
Kerosene is also expensive for people living in poverty. In rural India, for example, buying kerosene requires nearly 4 percent of a typical household budget. Finally, LED lamps are simply more efficient and provide more useful light. According to The Christian Science Monitor, LED lamps produce “nearly 200 times more useful light than a kerosene lamp and almost 50 times the amount of useful light of a conventional bulb.”

“This technology can light an entire rural village with less energy than that used by a single conventional 100 watt light bulb,” says Dave Irvine-Halliday, a professor of electrical engineering at the University of Calgary, Canada and the founder of Light Up the World Foundation (LUTW). Founded in 1997, LUTW has used solar-powered LED technology to light nearly 10,000 homes in 27 developing countries.

Strategies Needed to Reduce the Initial Cost of LED Solar Lamps
For the program to work long-term in India, GSBF says it will be necessary to lower the cost of the LED lamps by manufacturing them inside India instead of importing them from China and elsewhere. Manufacturing the lamps locally would lower the cost from $55 to $22 per unit, but building a factory would cost approximately $5 million, and investment capital is not easy to find.

Larry West,