Zepsor presents zero-power IR sensors

Technology News | May 23, 2023

By Peter Clarke

startup sensors Optoelectronics

Zepsor Technologies Inc. (Burlington, Mass.) is due to present technology – based on passive sensing using infrared energy – at the MEMS & Sensors Technology Conference.

The MSTC is a two-day event being held at the Massachusetts Institute of Technology Cambridge, Mass. on May 23 and 24.

Zepsor has designed and demonstrated a passive MEMS sensor that detects the thermal energy generated by a person, and then activates itself and other electronics without requiring any idle power. This allows for ‘always-on’ sensing at zero power consumption and event-driven wake-up of electronics.

In essence what Zepsor have done is build a light-activated micromechanical relay. The demonstration is a sensor that can detect the thermal energy generated by a person or other body. The benefit is reduced power consumption, reduced battery consumption, reduced battery changes and even the possibility of energy harvest based passive systems.

Operation of a micromechanical photoswitch that harvests energy from specific infrared radiations to implement abrupt ON/OFF switching without using any electrical power. Source: Zepsor Technologies Inc.

One of the refinements is that multiple light-activated MEMS, sensitive to different spectral bands can be made on the same chip and connected together to form passive logic circuits capable of detecting and discriminating spectral signatures while rejecting background interference.

The company is developing a family of zero-power sensors. The technology can be used for proximity detection, human body detection and, potentially, gesture detection to address a broad-range of applications from home automation through personal electronics and on to security and fire safety.

Zepsor was co-founded in January 2021 by Matteo Rinaldi, a professor at Northeastern University and Zhenyun Qian, who had gained his PhD and then conducted postdoctoral research under Rinaldi. The collaboration continues with Rinaldi serving as Zepsor’s CEO and Quan as CTO.

Meanwhile, the technology has received extensive incubation at Northeastern University since 2015. Funding has come from a series of DARPA awards, funds from the US Department of Homeland Security, from the Bill and Melinda Gates Foundation. The research breakthrough was reported in a paper published in Nature Nanotechnology – Zero-power infrared digitizers based on plasmonically enhanced micromechanical photoswitches – in September 2017.

Incubation

In January 2023, the Zepsor team was awarded a DARPA Small Business Innovation Research (SBIR) Phase II grant for US$1.8 million over a 3-year development project. In addition to this non-dilutive funding from DARPA, Zepsor also received an additional equity investment from Silicon Catalyst Angels and other seed-stage investors. The combination of these funds and earlier ARPA-E and DHS grants amount to a total of US$3 million raised from grants and equity investments.

At the time Zepsor announced its funding Rinaldi said in a statement: “We anticipate an exciting year as we start sampling our zero-power infrared sensors for proximity and presence detection.”

Zepsor has yet to reveal where it plans to have sensors manufactured in volume and what it’s business model will be.

STMicroelectronics has a similar technology that it calls TMOS that will also be presented at MSTC, although this is does not offer zero power consumption.

A TMOS, or thermal MOS sensor, is based on the silicon-on-insulator (SOI) manufacturing process. Infrared radiation in a field-of-view reaches a transistor gate that is thermally-insulated using MEMS fabrication. The IR energy alters the bias of the MOS transistor and is used to sense the temperature of objects or people.