EnOcean is partnering with the distributor Farnell element14 for a worldwide engineering design competition. Out of more than 200 applicants, 15 finalists were chosen. Their challenge now is to develop an innovative monitoring and automation application. All technologies provided to the challengers underpin the term “Internet of Things” (IoT).
The challenge aims to solve common everyday problems, such as remembering whether you've locked the front door, taken out the trash, or shut the oven off. Using energy harvesting wireless sensors, IoT technologies can transmit information to smartphones and tablets, giving the user a real-time update on such statuses.
The challengers were given a kit of several energy harvesting wireless sensors. In addition to a switch module using the electromechanical harvesting principle, the kit includes sensors that harvest light to power measurement and wireless communication.
Light is a great and almost ever present source of energy. Large solar farms are rising from the ground to ensure our energy requirements are met through renewable resources, and solar cells not larger than 13 x 35 mm enable maintenance-free sensor intelligence. These harvesters can even use indoor light to supply electricity for ultra-low-power wireless radio modules. Already at 200 Lux, the solar cells generate an operating voltage of 3 V. With 3.6 hours of charging in daytime, this provides a temperature sensor module enough power to transmit a measured value every 15 minutes in an uninterrupted operation mode, for example.
Using this technology, manufacturers around the world have already developed a broad range of self-powered sensors covering functionalities such as temperature, light, humidity, and presence detection. The next leap in the market is solar-powered multifunction sensors that cover CO2 levels, temperature, and humidity with one device. These sensors, powered by harvesting indoor light, measure and report levels of carbon dioxide, ambient temperature, and relative humidity in an internal environment. This is interesting, for example, for public buildings such as schools. The sensors can control air quality in classrooms to protect the pupils' health and foster a good learning environment. Connected to a gateway, the sensors can even inform the teacher via smartphone when the windows should be opened to freshen the air.
The energy harvesting technologies available today are still at an early evolution stage, waiting to unfold their potentials. Light will underpin them in its role as one of the most popular energy sources. Next-generation products will combine more efficient solar cells with improved performance under low light conditions. The limit of operation is light intensities of about 100 Lux at 5% efficiency today, but next-generation solar cells based on organic material or dye-sensitized technology will operate down to 10 Lux light intensity with more than 10% efficiency.
This will allow self-powered solar-based sensors to be placed in dark areas of buildings or even in dark corners of outdoor structures. Together with longer-range radio connection and further improved energy management, this lays the foundation for light-powered wireless sensors that permanently monitor critical parameters at large structures like bridges to warn against nonconformance and prevent breakdowns.
In the upcoming years, we will observe some revolutionary developments to energize further applications that lead to solutions where batteryless sensors are set to play an increasingly important role in solving everyday problems. I'm really excited and curious to see the applications of the 15 finalists in the element14 engineering competition. If you want to follow the challenge's progress, take a look at the finalists' blogs here.