Sensor Data, Images Hitch Ride With Wi-Fi-based Solution

Wavelite has commercialized a system from Stanford University that employs a modified Wi-Fi transmission to send everything from temperature and humidity data to pictures to a phone, tablet or laptop.
Published: July 13, 2018

A Canadian technology company is releasing a product that employs Wi-Fi transmissions to send sensor data or images wirelessly to a smartphone or other device, using an existing Wi-Fi network and its modified Wi-Fi signal. The technology could enable businesses to set up low-cost sensors around a facility or other location, and to capture pictures, as well as temperature levels or other data, to understand what is occurring there.

Wavelite, a Canadian Internet of Things (IoT) startup spun off from Stanford University research, is commercializing its Wi-Fi-based system, which enables users to set up an automated sensor and tracking system that utilizes a facility’s existing Wi-Fi network. The solution, known as HitchHike, was developed by a team of Stanford researchers led by Sachin Katti, an electrical engineering and computer science professor.

The HitchHike system was designed to be a low-cost alternative to RFID or BLE systems, since the data could be captured without requiring a reader appliance or gateway. Instead, the group developed a Wi-Fi tag that could be energized and prompted to transmit by the Wi-Fi router, and to then alter its signal and transmit it to a dedicated smartphone, tablet or computer. In that way, the system does not create a drag on the existing Wi-Fi network. In the meantime, the tag would capture any data from sensors connected to it, and that information would hitch a ride on that transmission.

The researchers, at the time, were using a tag measuring 1.29 inches by 1.94 inches, with a built-in envelope detector, to identify when a Wi-Fi signal had started. It also included a chip and an RF switch to reflect the signal from the router back to the receiving device (a phone, tablet or computer) on a different Wi-Fi channel.

Since Stanford’s early work, the technology has been developed and tested by Wavelite, says co-founder and CTO Bahar Partov. “We’re taking this technology and trying to make it applicable to demands in the market,” she says. Based on requests from potential customers, the firm has made several modifications and upgrades to the system, including enabling it to operate without requiring software updates on a Wi-Fi router. Instead, the solution simply receives existing Wi-Fi signals. It is then able to interpret reflected sensor data with software on the receiving phone or other mobile device.

The company is also miniaturizing the tag. While it previously measured about 4 centimeters (1.6 inches) square and 2 centimeters (0.8 inch) in thickness, the next version will measure approximately 1 centimeter (0.4 inch) square, with both chip and antenna. The tag has a transmission range of 10 to 50 meters (33 to 164 feet), Partov says, depending on line of sight and the environment. The miniaturized version is expected to be available in late 2019, while the larger version available now.

The tag is semi-passive, but can operate off Wi-Fi-harvested energy or a battery. If it is used as an active tag, it can be powered via a battery, and could be harvested from a photovoltaic cell.

In addition to environmental sensors, the system could also be connected to image sensors—cameras that take low-resolution, black-and-white images—and could transmit those images along with the tag’s unique ID. In that way, users could not only view environmental data from a specific location, but actually see pictures of that space, even if they weren’t there.

Users first configure the tags with a USB or wireless connection. That can include rules such as how frequently the tags transmit sensor data. The users download the Wavelite software onto their receiving device; Wavelite has been using Raspberry Pi for this purposes, Partov says. “The software is compatible with any Linux-based machine,” she states, and can work with the Matchbox open-source-base environment. Wavelite’s cloud-based software processes the data and makes it accessible to users, along with analytics enabling companies to better understand trends and identify problems.

One common use case for the system will be building automation, Partov says. In fact, she notes, a European building-automation technology provider, which has declined to be named, is now preparing to pilot the solution to enable its sensors to transmit data wirelessly. The tags will be connected to temperature, humidity and light sensors, and will be mounted on walls around the facilities of the company’s customers.

The sensor data will be collected and linked directly to the building-automation system. This information can then prompt the turning on and off of heat, air-conditioning and lighting systems. Several manufacturers based in the United States plan to pilot the technology to track air quality and conditions where semiconductors are being built. They have also asked to remain unnamed.

The collection of images is of interest for security purposes. The image-taking tags could be linked to motion sensors, and thus enable a picture to be taken every time an individual passes the tag—for instance, when someone enters or leaves through an egress to a secure building.

For testing purposes, Wavelite is initially providing end users with sensors and connected tags, but the tags could be purchased and then connected to any sensor of choice in the future. Some of the businesses working with Wavelite are already using ZigBee- or Bluetooth-enabled systems to manage conditions within a facility.

“The issue with these technologies is the power consumption,” Partov says. “Our solution is more sustainable.” In fact, she notes, Wavelite reduces the power consumption of wireless connectivity by a factor of 1,000 in comparison to a Bluetooth transceiver, and uses less than 100 microwatts of power. Since the technology enables users to better manage functions such as artificial light use, it also reduces energy consumption.

The cost of the tags would be less than a dollar, Partov says, with the price reducing in large volumes. In January 2018, the technology earned the company a Consumer Electronics Show (CES) Eureka Park Climate Change Innovators award.