RFID Doing More Than ID

RFID is a workhorse in industrial, commercial, and consumer markets. Passive tags, like work badges and key fobs, need a base station but not the tags. Sensors are a big market and putting sensors in places that are hard to reach, hostile, or mobile is a costly proposition. That price could drop, and the sensors could be more approachable with help from MIT’s Auto-ID Lab who are experimenting with sensor feedback to RFID devices.

Let’s pretend you want to measure the temperature inside a vat of pressurized acid. You’d rather not drill a hole in it to insert a thermometer, but a temperature sensor sealed in Pyrex that wirelessly transmits the data and never runs out of power is a permanent and cheap solution. The researchers have their sights set on glucose sensing and that news come shortly after Alphabet gave up their RFID quest to measure glucose through contact lenses. Shown the top of this article is a prototype for a Battery Assisted Passive (BAP) RFID sensor that uses commodity glucose testing strips, sending data when the electrochemical reaction occurs. It uses six of these cells in parallel to achieve a high enough peak current to trigger the transmission. But the paper (10.1109/RFID.2018.8376201 behind paywall) mentions a few strategies to improve upon this. However, it does prove the concept that the current spike from the test strips determines the time the tag is active and that can be correlated to the blood glucose detected.

How many of our own projects would instantly upgrade with the addition of a few sensors that were previously unobtainable on a hacker budget? Would beer be brewed more effectively with more monitoring? How many wearables would be feasible with battery-free attachments? The sky is the figurative limit.

Thank you, [QES] for the tip [via TechXplore]

THP Quarterfinalist: Hypoglycaemia

For somewhat obvious reasons, there aren’t many medical hacks making their way to the quarterfinal selection of The Hackaday Prize. One exception to this is [Thomas]’ Hypoglycaemia Alert System, a Bluetooth device that detects low blood sugar in sleeping diabetics and calls for help.

This isn’t the only blood glucose monitor that made it to the quarterfinals of The Hackaday Prize. [John Costik] reverse engineered a continuous glucose monitor for his Type 1 son (we also did a hacker bio on him). This project has a slightly different scope and doesn’t rely on pre-existing blood glucose sensors. In fact, it doesn’t detect glucose at all. Instead, it uses humidity and temperature sensors to detect the heavy sweating that often occurs with low blood glucose levels.

This hypoglycaemia monitor is meant to be worn by a user at night. Glucose levels can drop while sleeping, and if they drop too low blood sugar can result in death. When the monitor detects the symptoms of low blood glucose, it connects to a smartphone through a Bluetooth link and sends an SMS alert to phone numbers in the contact list. Whoever receives this message will then try to wake the potentially unresponsive diabetic, and failing that, would put some cake frosting under their gums (Seriously. Ask a police officer/EMT for cake frosting. The good ones have some).

[Thomas] is well on his way to a functional device despite having a few problems with his enclosure. Right now he’s working on the Bluetooth comms part of the build, and we hope a complete, working device is right around the corner.


SpaceWrencherThe project featured in this post is a semifinalist in The Hackaday Prize.