It is important to change the wet diaper of infants at appropriate time. Because if worn too long, a wet diaper can cause painful rashes, and miserable babies — and parents.
Now MIT researchers have developed a “smart” diaper embedded with a moisture sensor that can alert a caregiver when a diaper is wet. When the sensor detects dampness in the diaper, it sends a signal to a nearby receiver, which in turn can send a notification to a smartphone or computer.
The sensor consists of a passive radio frequency identification (RFID) tag, that is placed below a layer of super absorbent polymer, a type of hydrogel that is typically used in diapers to soak up moisture. When the hydrogel is wet, the material expands and becomes slightly conductive — enough to trigger the RFID tag to send a radio signal to an RFID reader up to 1 meter away.
The researchers say the design is the first demonstration of hydrogel as a functional antenna element for moisture sensing in diapers using RFID. They estimate that the sensor costs less than 2 cents to manufacture, making it a low-cost, disposable alternative to other smart diaper technology.
Over time, smart diapers may help record and identify certain health problems, such as signs of constipation or incontinence. The new sensor may be especially useful for nurses working in neonatal units and caring for multiple babies at a time.
And this sensor could also be integrated into adult diapers, for patients who might be unaware or too embarrassed to report themselves that a change is needed.
Many off-the-shelf diapers incorporate wetness indicators in the form of strips, printed along the outside of a diaper, that change color when wet — a design that usually requires removing multiple layers of clothing to be able to see the actual diaper.
Companies looking into smart diaper technology are considering wetness sensors that are wireless or Bluetooth-enabled, with devices that attach to a diaper’s exterior, along with bulky batteries to power long-range connections to the internet. These sensors are designed to be reusable, requiring a caregiver to remove and clean the sensor before attaching it to each new diaper. Current sensors being explored for smart diapers, retail for over $40.
RFID tags in contrast are low-cost and disposable, and can be printed in rolls of individual stickers, similar to barcode tags.
A typical RFID tag has two elements: an antenna for backscattering radio frequency signals, and an RFID chip that stores the tag’s information, such as the specific product that the tag is affixed to. RFID tags don’t require batteries; they receive energy in the form of radio waves emitted by an RFID reader. When an RFID tag picks up this energy, its antenna activates the RFID chip, which tweaks the radio waves and sends a signal back to the reader, with its information encoded within the waves. This is how, for instance, products labeled with RFID tags can be identified and tracked.
News Source: MIT
