Smart Underwear



Millions of women use absorbent products to discreetly and successfully manage their continence needs.  However, many women worry that the product might leak wetness into clothes and furnishings, causing hygiene problems and more importantly, embarrassment. The Smart underwear is the only technology available to warn continence pad users that their pad has begun to leak.


The TACT3 Smart underwear is specially designed underwear with an integral sensor that allows the garment to be worn and washed normally. A removable electronic signalling unit is attached to the underwear and if any leakage of liquid from the absorbent product occurs, the unit discreetly vibrates to alert the wearer.  This early warning is designed to allow the wearer to change before wetness spreads beyond the underwear.


The Smart underwear's key component is an electro-conductive yarn sensor that is incorporated into the garment without detriment to the appearance, comfort or washability of the product. Coupled with a discreet signalling unit that can subtly alert the wearer to pad leakages the Smart underwear has been shown to help wearers feel more confident in a range of social situations.


Main Features

The signalling unit consists of a single round printed circuit board on which is mounted a microcontroller, a vibration unit, a coin cell and associated drivers.  The device is normally on and in a mode which uses minimal power (deep sleep mode).  It is activated when urine spills over from the pad, and bridges the gap between conductive pathways sewn into the specially designed underwear.  Connecting the pathways, activates the signalling unit.  When thus activated, the microcontroller begins a sequence to energize the vibration unit.  This vibration alerts the wearer of the underwear to the overflow of urine from the pad. 



  • Provides confidence and assurance for women who are concerned about continence pad leakage.
  • The smart underwear could also be used by carers to detect pad leakage by the addition of a transmitter.  This version would be for night-time use by people with profound learning disability, or by older people in residential care. This would relieve carers of the work of checking beds for wetness, and ensure a more peaceful night for residents

Developmental Status

Working prototypes extensively tested by end users



Demonstration of system available


IP Status

Available for licensing (UK Design Registration)



The signalling unit is connected via press studs, to the underwear and two parallel conductive pathways embroidered into the underwear, which act as the sensor. The pathways are isolated from the skin by a fabric layer. When urine leaks from the user's pad into the underwear fabric, electrical contact is made between the two pathways, triggering the signalling unit to activate. The embroidered sensor acts as a switch, which is closed by the leaked urine.  No current flows through the conductive pathways until urine makes an electrically conductive bridge between them. When this happens, 10μA flows through the conductive pathways. This extremely low current is sufficient to trigger the electronics, but is significantly below the minimum human detectable limit of 1mA. The presence of the current flowing through this device is therefore imperceptible to the wearer. The remainder of the electronics is encapsulated in a sealed enclosure and is isolated from the wearer.


When the system activates, it runs two brief series of vibrations during which it vibrates three times, each vibration burst being for 500ms, with a gap of 1s. The system then waits for 30 seconds and re-interrogates the sensor. If there is still contact between the conductive pathways, the system switches back into deep sleep mode and is not reactivated until the system is disconnected from the wet underwear and there is no longer electrical connection between the two contacts.  The system is powered by a non-rechargeable 3V Lithium coin cell and its overall dimensions are (44x11)mm.



Patent Information:
Medical Technology
For Information, Contact:
Averil Horton
Commercialisation - Brunel University
University of Surrey
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