Now, charge your phone simply by sending text message
London: People living off-grid can now power their phones simply by sending a text message.
A London-based company Buffalo Grid has introduced a solar-powered cellphone charging station that is activated by text message to help people in rural areas in the developing world, particularly in Africa and Asia, where electricity is irregular, according to the New Scientist.
At the Konokoyi coffee cooperative on the edge of Uganda's Mount Elgon national park, Juliet Nandutu is trying out the new device by offering the service to her village. She said she helps charge 18 phones a day, and sometimes 20.
A patchy or absent power grid poses a problem for farmers, who depend on cellphones to get up-to-date pricing information for nearby and distant markets, that allow them to better manage the sales of their crops.
When there is no electricity in their village, people have to trek for kilometres to a nearby town to find a charging station, powered by diesel generators or solar panels. But again it doesn't come cheap.
In Uganda, charging a cellphone can cost 500 Ugandan shillings, or about 0.20 dollars.
"In rural economies, about 50 per cent of the money spent on mobile phones is actually spent on charging them. That is some of the most expensive electricity in the world," said Buffalo Grid's Damon Millar.
Buffalo Grid's basic technology, which was recently trialled in Uganda, is a new hope for the villagers.
A 60-watt solar panel charges a battery that is taken to the village on the back of a bicycle. The battery extracts power from the solar panel using a technique called maximum power point tracking (MPPT).
A solar panel's power output is dictated by environmental conditions, such as temperature and the amount of sunlight, as well as the resistance of the circuits connected to it. MPPT monitors the conditions and changes the resistance to ensure the maximum possible power output at any given time.
The best part of the device is the way the stored power is released to charge a phone.
A customer sends a text message, which in Uganda costs 110 shillings, to the device. Once it receives the message, an LED above a socket on the battery lights up, indicating that it is ready to charge a phone.
At the Konokoyi coffee cooperative, each text message allows a phone to be charged for 1.5 hours. A fully charged Buffalo Grid unit can last for three days, has up to 10 charging points and charges 30 to 50 phones a day.
To make it cheaper, Buffalo Grid hopes to co-opt the cellphone network operators into subsidising power for charging the phones, or even making it free.
Buffalo Grid is also planning to do trials in Sierra Leone, where coffee traders are gearing up to pay farmers for their crop using cellphones.