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"Generating electricity is not only inefficient, it also makes pedal power less sustainable, less robust and more costly. To begin with, batteries have to be manufactured, and they have to be replaced regularly. This requires energy, which can completely negate the ecological advantage of pedal power. According to this research paper (pdf), the embodied energy of a 150Wh lead-acid battery (like the one offered with the Windstream pedal power generator) is at least 37,500 Wh, which equals 250 full charges of the battery (more sources: 1/2). In other words: if you can deliver 75 watts of power to the battery, you have to pedal for 500 hours in order to generate the energy that was needed to manufacture the battery. Because the life expectancy of a lead-acid battery can be as low as 300 discharge/charge cycles (sources: 1/2), you are basically pedalling to produce the energy required to manufacture the battery. If you also factor in the embodied energy of other electronics and parts, the ecological advantage of a pedal powered generator connected to a battery becomes rather doubtful. It might costs more energy than it delivers."

"Generating electricity is not only inefficient, it also makes pedal power less sustainable, less robust and more costly. To begin with, batteries have to be manufactured, and they have to be replaced regularly. This requires energy, which can completely negate the ecological advantage of pedal power. According to this research paper (pdf), the embodied energy of a 150Wh lead-acid battery (like the one offered with the Windstream pedal power generator) is at least 37,500 Wh, which equals 250 full charges of the battery (more sources: 1/2). In other words: if you can deliver 75 watts of power to the battery, you have to pedal for 500 hours in order to generate the energy that was needed to manufacture the battery. Because the life expectancy of a lead-acid battery can be as low as 300 discharge/charge cycles (sources: 1/2), you are basically pedalling to produce the energy required to manufacture the battery. If you also factor in the embodied energy of other electronics and parts, the ecological advantage of a pedal powered generator connected to a battery becomes rather doubtful. It might costs more energy than it delivers."

"- USB DC-DC Boost Converter BUY: http://goo.gl/H4QwUV - Solar Panel BUY: http://goo.gl/KF4mLG - AA Rechargeable Ni-MH Batteries BUY: http://goo.gl/y2n8eI - Latching Pushbutton Switch BUY: http://goo.gl/0gsxTd - Zener Diode BUY: http://goo.gl/0EvPBy - 47k Resistors - 51k Resistors - Electrical Tape - Wire BUY: http://goo.gl/apObBI Schematic: https://goo.gl/wWXtr1"

"- USB DC-DC Boost Converter BUY: http://goo.gl/H4QwUV - Solar Panel BUY: http://goo.gl/KF4mLG - AA Rechargeable Ni-MH Batteries BUY: http://goo.gl/y2n8eI - Latching Pushbutton Switch BUY: http://goo.gl/0gsxTd - Zener Diode BUY: http://goo.gl/0EvPBy - 47k Resistors - 51k Resistors - Electrical Tape - Wire BUY: http://goo.gl/apObBI Schematic: https://goo.gl/wWXtr1"

"The Fairphone is a modular handset designed with repairability and ethical sourcing of its materials as headline features. It sold 60,000 units. Amazingly, for what sounds like a nerd-phone, almost half of those buyers had never owned a smartphone before. Now the Fairphone 2 is launching, and with a totally-new, in-house design. The new phone is even easier to repair, and because it was wholly designed by the FairPhone team, its supply chain is even more responsible than ever. The Fairphone is thicker than the latest iPhone or Samsung flagship, but that's the point. Instead of packing everything into a tiny case and keeping it there with glue, the Fairphone is designed to be taken apart. The lightweight magnesium frame supports modules that can be easily replaced by the user. "We have designed it with an aim to last three to five years, looking at making it robust and modular-for repairability," says Fairphone's chief communications officer, Tessa Wernink. "Obviously how long it lasts depends quite heavily on the user, so what we as a company are doing is offering an ecosystem around the phone that supports long-lasting use, first-hand or second-hand." Inside the case (itself one of several options) you'll find the core unit, containing all the chips and radios; a replaceable battery pack; a display that can be snapped off and replaced without any tools (not even a screwdriver); a receiver unit, which contains the front camera, sensors; the headset connector and microphones; a speaker/vibrator unit; and a camera module. These modules are designed to balance manufacturing complexity with repairability. For instance, the display comes as a standalone unit, but less-vulnerable components are bundled into one module. The camera, which people are most likely to upgrade as better versions become available, is also housed in its own module. That way you don't need to toss out your whole phone just to get a better camera. "In fact, the motto from the maker mo

"Take a look inside Alibaba's smart warehouse where robots do 70% of the work. They can carry up to 500 kilograms above them around the warehouse floor. They have special sensors to avoid colliding into each other and they can be summoned using wifi. When they run out of battery, they can take themselves to a charging station. A five minute charge can power them for 4/5 hours."

"Every smartphone in the world has an FM tuner built in. But here in the US, just one-third of them actually works, even though the Federal Emergency Management Agency says radio can save lives in an emergency. "We know that if Internet networks or cell phone networks go down, FM still works so long as you have a battery to turn the device on," says agency spokesman Rafael Lemaitre."

"In this Instructable, I'm going to be showing you how to build your own crack the code game in which you use a rotary encoder dial to guess the randomly generated code to the safe. There are 8 LEDs on the front of the safe to tell you how many of the digits you've guessed are correct and how many are in the right place as well. The safe is initially open, allowing you to put something into the inside compartment. The Arduino and battery are housed in a separate compartment in the back. You then push the dial to lock the safe, which is done using a servo on the inside of the door. You then need to input the code by turning the dial to select the digits and pushing the dial to confirm each digit. After your fourth digit is chosen, the safe displays how many of your digits are correct and how many of them are in the correct place using the red and green LEDs on the door. "

"En Jujuy habilitaron la minería en zonas de comunidades que no fueron consultadas. En Catamarca, se triplicó la inversión. Las asambleas denuncian impacto ambiental y riesgo del agua. "Oro blanco", bautizaron al litio, mineral que se utiliza en baterías de celulares, computadoras y autos eléctricos. Científicos, funcionarios, empresarios y periodistas llaman a explotar esa "riqueza natural" presente en las salinas de Jujuy, Salta y Catamarca. Pero no tienen presente que allí viven comunidades indígenas con derechos sobre esos territorios y vecinos que rechazan la minería por sus impactos ambientales y sociales. La explotación de litio forma parte del modelo extractivo, junto a la megaminería metalífera (oro, cobre, plata, plomo, entre otros), agronegocio, petróleo y forestales. Aunque suele publicitarse como "energía limpia", su extracción implica sobreconsumo de fuentes de agua y uso de químicos contaminantes."

"A diferencia de la TRE (Tasa de Retorno Energética, ERoEI por sus siglas en inglés), éste tiene los límites muy bien definidos y fáciles de calcular, puesto que trata de la cantidad de energía que devolvería un sistema de almacenamiento a lo largo de toda su vida útil teórica, al respecto de la inversión económica hecha en la misma, al margen de elementos accesorios (aunque imprescindibles la mayoría de las veces), y del coste de la energía que hay que meter en el sistema para obtener la batería, aunque esto último es necesario tenerlo en cuenta para otros elementos de la contabilidad energética y económica. Nada como un ejemplo para entender el concepto de forma fácil. Para el caso, uno de los elementos estrella en los análisis de ESOI, un conocido del autor, y material referenciado en otras partes: una batería de litio, que para el caso, puede ser la de un teléfono móvil. Pongamos por caso, una celda prismática de Litio-polímero de 3000mAh de las que usan habitualmente algunos Smartphone. El rango de precios suele estar entre 15 y 20€, dependiendo de varios factores. De esta manera, tenemos la mitad fácil del cálculo, el Investment o inversión. Pongamos 10€, tirando por lo bajini. Y fácil: sin financiación ni intermediarios ni impuestos ni intereses ni nada. Ahora, pues, viene la parte difícil. ¿Cuánta energía almacenará esta batería a lo largo de su vida útil?"