IoT startup makes battery-free sensors

A startup founded by two MIT grads says that it can deploy self-powering sensors to handle low-intensity IoT tasks, eliminating the need for batteries or power cabling and adding a new level of flexibility to IoT deployments.

Ben Calhoun and Dave Wentzloff are the founders of Everactive, an IoT-device startup whose sensor modules can create their own power from a variety of sources, including indoor solar that gathers energy from artificial lighting, and thermal-gradient differential using waste heat to generate electricity. These techniques don’t generate a lot of power but don’t need to for Everactive’s purposes.

The sensors themselves can monitor for temperature, humidity, light levels, vibration, movement, sound,  and pressure, among other things.

The sensors attack the power problem from the demand side, as well. The company employs sub-microwatt wakeup receivers for its radios, ultra-low-power integrated circuits, and other power-saving technology that allows the sensors to operate with minimal power.

Both thermal-gradient power and indoor solar are relatively well-understood technologies, but the ability to combine them with devices that have very low power consumption is what the company says allows it to offer completely self-powered IoT sensor networks.

Everactive bills itself as a full-stack solution, sending data via a proprietary low-power network directly to an on-premises gateway that’s able to handle hundreds of sensors at a time and that connects to Everactive’s Evercloud back-end for monitoring and analysis. The broadcast range of a sensor is 800 feet.

The protocol used by the sensors doesn’t use duty cycling or other transmission halts to save energy, so the network is always active. The sensors transmit on a sub-GHz frequency so it propagates well through walls and other objects.

The real monetary value of self-powered IoT sensors is mostly in operational savings, the company says. A deployment of several thousand battery-powered sensors, even with lifespans of several years at a time, represents a substantial sum in work hours to replace batteries, plus the cost of the batteries themselves.

Self-powering also makes certain IoT use cases much more practicable. For example, Changing the batteries in a sensor monitoring the rim of a volcano is not a trivial task, so these sensors could be a boon to IoT networks with sensors in similarly remote or dangerous locations.

The company’s showpiece product, so far, is a monitoring system for steam-traps—valves that vent waste materials without actually losing any live steam in the system. By using its networked sensors, facility operators whose duties include monitoring steam traps can see potential problems remotely as they happen instead of manually inspecting the traps and never have to replace batteries. Other use cases, including remote-asset monitoring, are under development.