The era of the “connected refrigerator” may have arrived, but Mark Roemers, co-founder of Netherlands-based AntTail, has simply given up on consumer refrigerators, smart or otherwise. They don’t cool evenly, with a dozen or more degrees Fahrenheit temperature difference between storage in the door and storage in the back of a typical refrigerator — more than enough to allow for degradation of certain medications. And AntTail, which focuses on pharmaceutical logistics, is all about keeping medicines fresh. Part of its partnership with one of the major pharmaceutical suppliers in the Netherlands is to supply small drug storage coolers to individual patients to use in their homes.
Using refrigerators, more than 90% of patients don’t store their medications within the safety margin. Using the dedicated cooler turns that statistic exactly on its head. AntTail knows this because it tracks the temperature continuously and monitors when the drugs are accessed for use.
The company has developed a small sensor that fits inside the sealed package in which pharmacies deliver drugs to patients. The sensor device, which looks somewhat like an overgrown SD card, not only tracks temperatures, but also incorporates a light sensor so it knows when the package it resides in has been opened. With a life between battery changes of 18 months, it’s something of a textbook example of these sorts of communications and power-consumption issues that real-world IoT devices must deal with.
The first casualty of power requirements for AntTail, Roemers says, was industry standards. The company really couldn’t use conventional wireless standards such as Wi-Fi, Bluetooth, Zigbee or Z-wave– it’d have only managed six months or so of life from the CR2032 batteries that its sensors use — and thus have invented its own proprietary network. “There’s a big need for someone to come up with a standard for very efficient wireless communication,” Roemers said.
The proprietary AntTail protocol is unusual in that it doesn’t use addressed-based routing the way IP-style networks do. Instead, each device monitors the hop counts of packets traversing other nearby units (this is a mesh architecture) and sends packets to devices that it knows are “upstream” in relation to an aggregator (think, roughly, of a Wi-Fi access point). The aggregator then uses a cellular data connection to send the sensor data to the cloud. If the company had chosen a standard protocol for local connection to the sensors, Roemers said, it would have been Zigbee, but then “all the equipment would be six times larger” because of the extra batteries needed.
Data from the sensors is collected in the cloud and, of late, some of it is shared back to patients by way of a smartphone app, which helps with reminders to take medicines on schedule. At present, there are only about 1,000 sensors in the field, but the deployment is doubling monthly. One downside: fully one half of the sensors are thrown away by patients who forget that they are inside the foil pack containing the medicine. AntTail notes that they do typically get a couple of trips to the end user and back before they go astray. Still, at thirty euros a throw for the sensor units, IoT medicine delivery is still a pricey proposition.