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Diaper sensor technology to save babies from rashes


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Researchers say the design shows that hydrogel can work as a signalling material

Wednesday February 26 2020

Awful baby diaper rash could soon be a thing of the past after researchers developed a “smart” diaper implanted with a moisture sensor that can alert a caregiver when a diaper is wet.

Researchers at Massachusetts Institute of Technology said this will help caregivers to change the baby’s diaper when it gets wet as opposed to waiting until the baby cries to express discomfort.

According to one of the researchers and project engineer and research assistant at AutoID Laboratory Pankhuri Sen, the smart diaper sensor types currently sold by other firms cost more than USD40 (Sh4,032) each. On the other hand, radio frequency identification (RFID) tags are much cheaper and disposable. Like supermarket bar code tags, these RFID tags can be printed in rolls of individual stickers.

The researchers say the design shows that hydrogel can work as a signalling material for RFID tags to detect moisture in diapers. In their estimates, the sensor will cost less than Sh2 to manufacture. This makes it a cheap, disposable and affordable version of smart diaper technology.

The results of the research were published in the IEEE Sensors Journal on February 14.

Most caregivers will take some time to interpret a baby’s cry to mean his or her diaper is wet. However, not all babies cry when the diaper is wet and this exposes the passive ones to painful rashes later on.

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The sensor is made up of a passive radio frequency identification (RFID) tag, which is placed below a layer of hydrogel, a material normally used in diapers to absorb moisture.

When the diaper gets wet or damp, the sensor sends a signal to a nearby receiver, which can then send a notification to a smartphone or computer. When the hydrogel becomes damp, the material expands and can conduct electric current, triggering the RFID tag to send a radio signal to an RFID reader up to one metre away.

An ordinary RFID tag consists of an antenna for reflecting or bouncing back radio signals to the general direction where they came from in a process called backscattering.

It also contains an RFID chip that stores the tag’s information, such as the specific product the tag is attached to. In order to function, RFID tags receive energy in the form of radio waves emitted by an RFID reader.

The tags do not require batteries or any other power source. When an RFID tag detects this type of signal, 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 enables products with RFID tags to be identified and tracked.

Going forward, Sen suggested that the sensor could also be used in adult diapers for patients who might be unaware or too embarrassed to request for a change of fresh diapers. “Diapers are used not just for babies, but for ageing populations or patients who are bedridden and unable to take care of themselves,” said Sen.