As organizations seek strategies to keep people safe while balancing the need to operate their businesses, wireless temperature sensors are seen as a way to make processes as contactless as possible. As the world moves into month five of the COVID-19 pandemic and the practicalities of emerging from various stages of safe isolation are being addressed. From essential businesses that have remained operational to schools and universities facing the prospect of returning to classes in the Fall, mitigating the risks that come with large gatherings is at the top of everyone’s list of priorities. Administrators and managers can take appropriate measures, starting with an economical, easy-to-use, and ultra-fast method for detecting potential health risks, to balance the anxiety that comes with possible exposure with the pressures of keeping businesses, schools, cities, and economies up and running.

One way this challenge is being met is through technology. Silicon Labs is excited to be part of a coordinated effort to develop a low-cost, contactless wrist temperature sensor that can be used to determine whether or not an individual is within the acceptable temperature range. Screening individuals for fever is a strategy that’s been deployed by organizations when isolation or social distancing simply isn’t an option. And while there’s so much we don’t know about COVID-19, temperature checks may be an effective way to identify a symptom even before the individual experiences any symptoms.

The TTI Family of Companies (FOC), which includes Connected Development, Symmetry, and Mouser, together with TE Connectivity, have joined forces to develop an open-source, contactless wrist temperature sensor. Cost-effective and easy to use, the temperature sensor is based on the Silicon Labs EFM32 Tiny Gecko TG11 Starter Kit, which is used to collect temperature sensor information from the thermopile and to notify the end-user of results.

The contact sensor is already being used by TTI employees at its warehouse locations where employees entering the facility simply hold their wrist near the sensor. They receive an instant reading of their temperature, which is accompanied by beep noise and a red or green light indicating if they are at or above the acceptable temperature range. Connected Development (CD) designed and prototyped the sensor; they specialize in hardware and software design services. CD tapped into TTI FOC’s extensive network of component distributors and services, with contributions from TTI, Symmetry Electronics, and Mouser Electronics, to develop this open-source design.

In addition to the Silicon Labs Tiny Gecko Starter Kit, the sensor design features a TE TSD305 Digital Thermopile Sensor for temperature measurements, a TDK Piezoelectric Buzzer for audio feedback, and Cree PLCC6 3 in 1 SMD LEDs provide the visual cues. Aside from body temperature, the thermopile sensor can also detect when a person is within range to take a measurement. The Tiny Gecko constantly regulates the thermopile for temperature fluctuations, and if the temperature rises above 90 degrees Fahrenheit, it is assumed that a human body is close by, prompting a measurement cycle to begin. The microcontroller then awaits a consistent measurement, which is achieved by capturing three readings in a row that are within one degree of each other. Once a stable measurement is captured, the temperature is displayed on the starter kit’s LCD. The TDK Piezoelectric Buzzer then sounds, which is accompanied by a green light from the Cree LEDs if the temperature is below 100.4 degrees Fahrenheit, or a long beep with a red LED light if the temperature is higher than 100.4 degrees Fahrenheit.

If you’re considering developing a contact sensor to help bring clarity to the health of your workforce, there are a couple of different ways we can help you realize that goal. The first is during the first-ever Silicon Labs Works With Smart Home Developer Event. David Hoover, VP of Advanced Development at Connected Development, will be presenting a tutorial showing how to interface a TE thermopile sensor with the EFR32xG22 Wireless Gecko Starter Kit, which includes all you need to create a Bluetooth connected device. David will also demonstrate how to use Silicon Labs’ Simplicity Studio to send the resulting temperature to an IOS device using Bluetooth services and characteristics. The first Works With virtual event, taking place on September 9-10, will bring together our ecosystem of partners from Amazon, Google, Samsung, Z-Wave, and more for keynotes, panels, and hands-on workshops.

If you can’t attend the workshop, our friends at Mouser Electronics have developed a detailed, step-by-step technical article on how to develop the contact sensor, calibrate it, and start using it. You can also explore open-source contactless sensor documentation on GitHub.