Can you feel it? There’s a certain energy in the air. Cell towers, radio and TV transmitters, satellites, WiFi routers, and other sources of radio waves are constantly emitting electromagnetic energy. Movements and vibrations are forms of mechanical energy. There’s light and heat all around. Can we tap into that “free” energy and use it to power our electronics? Yes!
In this first installment of a multi-part article, I’ll give an overview of energy harvesting and some of its applications. Later installments will explore various methods of energy harvesting in greater detail.
Energy Harvesting: The Big Picture
Let’s start with the obvious: you’re not going to recharge your Chevy Volt or power your 52-inch TV by harvesting ambient energy. We’re talking microwatts and milliwatts in most cases. While that may seem small, think about a solar-powered calculator: it never needs batteries because it uses ambient light to produce the small amount of energy it consumes. How many other devices use just a trickle of energy? Hearing aids, MP3 players, remote sensors … there’s a lot. And with the proliferation of low-power microcontrollers and smart sensors, the list keeps growing. Now eliminate the batteries from all of those devices and you reduce pollution while increasing reliability and convenience. In cases where ambient energy isn’t always available when needed, the new generation of supercapacitors can be used for storage. And light isn’t the only source of energy that’s available. Imagine a pacemaker that's powered by the vibrations of the heart itself! Check out this slideshow for more...What products are you designing that might take advantage of energy harvesting?