This week’s EYE ON NPI (video) is a self-starting go-getter, it’s the EDK350/EDK350U Developer Kits from EnOcean – containing everything you need to get started with energy-harvesting / self-powered sensors.
These kits are a great way to explore and understand the EnOcean series of solar and mechanical energy-harvesting switches and sensors.
As engineers, we’re often tasked with ‘smartening up’ existing structures: whether that’s machinery, agriculture, buildings, cars, appliances, etc. The last few decades have given us ultra-cheap sensors and radios – which means we are able to gather data from a wide area and store it centrally, the Internet of Things! That means just about every project and product you will work on is going to have sensors, data storage and wireless – but with great technology comes great complexity: you now have to worry about shuffling that sensor data around, and nothing eats up batteries like constantly having to wake up and transmit radio data.
In fact, a lot of the really tough engineering with sensor networks is not in picking the radio or sensor but in how to keep the battery lasting as long as possible. Particularly since folks like products with small, rechargeable batteries – but they don’t like having to constantly plug them in. Moreover it’s really hard to let people know when something needs to be recharged – there’s the problem of “well we need power to blink an LED or sound a buzzer which will drain the power even faster – but if we blink or buzz too rarely it may not be caught in time to change out the battery before it dies”.
Also known as the ‘smoke detector issue’ – Americans kind of solved this by starting a campaign to check smoke detector batteries on every daylight savings change. Great for individual households with maybe 3 or 4 smoke detectors – not great if you have dozens or hundreds of light switches or soil moisture sensors.
EnOcean solved this in a typically engineer-y fashion: what if, instead of having batteries which add cost, maintenance and life-cycle management…we just didn’t? Instead, their devices use energy harvesting, which means that – in theory – there is no installation or maintenance costs at all. Once installed, it will forever sip power from motion or ambient light until there’s enough power for a transmission. EnOcean even has their own low power 900/868MHz radio modules with integrated 8051’s that are specifically designed for quick startup, sensing, transmission and power down.
The most famous is their ECO200 mechanical energy harvesting switch, which also made it into the Philips Hue wireless lighting system, a great fit since the whole system is wireless, and there’s a natural inclination to associate pressing a button with changing the light settings.
In addition to the classic mechanically-powered switches, there’s also a series of micro-solar powered sensors, good when you need to have a slow but continuous measurement of environment. Tuck these near a fluorescent light fixture and you could sip enough power to send data once every few hours or per day – no wiring or installation required.
If this technology is something you want to look into integrating, you can get started with the EnOcean EDK350/EDK350U Developer Kit, a chocolate box assortment containing one of each of EnOcean’s sensors and switches. You get radios, USB sticks, mechanical and solar harvesters! Available in both 900MHz for Americans, or 868MHz for Europe / Asia. And both kits are in stock right now for immediate shipment from Digi-Key! Order today and you will be energy harvesting by tomorrow afternoon.
Check out the videos below also.