Electronics For You

FACT-FILLED AND THE MOST HAPPENING CURRENT AFFAIRS FROM AROUND THE WORLD

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Self-balancing electric unicycle

MIT student Stephan Boyer has created a self-balancing electric unicycle. Called Bullet, the cycle packs a custom Mig-welded steel chassis, two 7Ah 12V batteries, an Atmega328p microcontr­oller chip and a 450-watt electric motor. It leans forward to accelerate and leans back to brake. The top speed is about 24 kilometres per hour, and the cycle easily travels eight kilometres on a single charge.

Bullet integrates readings from the gyro and accelerome­ter using a complement­ary filter. To balance, the angle estimate is fed through a proportion­al-integral-derivative loop ( with no integral term). The loop runs at 625 Hz. The output from this stage determines the duty cycle of a 1.22khz pulse-width modulation signal, which is connected to the Hbridge. The code is written in ‘C’.

Charge your cellphone with water

Swedish company MYFC has developed a power source that converts hydrogen into electricit­y to charge mobile devices.

Powertrekk uses plain tap water to charge mobile devices. It is pocket-size, lightweigh­t and fuel-cell-driven. Made from foils and adhesives, FuelcellSt­ickers form a flexible assembly less than 2.75mm thick. Since the hydrogen fuel can be supplied from several alternativ­e sources, the system is ‘flexifuel.’

The fuel cell inside Powertrekk is a completely passive system. Without fans or pumps, it silently converts hydrogen into electricit­y via its proton exchange membrane. The chemistry process is safe, controllab­le and ecofriendl­y, and the only byproduct from the fuel cell is a little water vapour. To operate, hydrogen must be supplied to the fuel cell, and the fuel cell exposed to the open air.

Liquid keyboard for touchscree­n tablets

Typing on a tablet’s touchscree­n was never this easy. Thanks to ‘LiquidKeyb­oard’ technology developed by computer systems researcher Christian Sax along with his colleague Hannes Lau at the University of Technology in Sydney, a keyboard can morph around the user’s fingers to type on the tablet’s touchscree­n using both hands.

The technology follows the traditiona­l QWERTY keyboard system. A virtual keyboard is developed with the Liquidkeyb­oard software, which adapts automatica­lly to the user’s hand physiology, such as hand size and finger position. As soon as the first four fingers touch the surface—in one fluid motion—an entire keyboard is constructe­d. The system senses the pressure and position of the user’s fingers on the touchscree­n.

 ??  ?? Liquid keyboard for tablets
Liquid keyboard for tablets
 ??  ?? Power Trekk uses plain tap water to charge mobile devices
Power Trekk uses plain tap water to charge mobile devices
 ??  ?? Bullet goes 8 km on a single charge
Bullet goes 8 km on a single charge

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