Whatever next? Introducing the 'goose bump' sensor
25 June 2014
Can emotional states be measured quantitatively and, if so, what could advertising, manufacturing and social media companies do with that data?
Imagine a world in which a consumer's real-time physical and emotional response helped to determine his or her experience of music, online advertisements or the temperature in the room. That may not be so far away, if the work of Korean researchers is to be taken at all seriously.
The research team, from the Korea Advanced Institute of Science and Technology (KAIST), has developed a flexible, wearable 20mm x 20mm polymer sensor that can directly measure the degree and occurrence on the skin of goose bumps (technically known as 'piloerection'), which is caused by sudden changes in body temperature or emotional states.
Described in an article in the journal Applied Physics Letters, the technology is based on a coplanar capacitor and detects goose bumps by virtue of a simple, linear relation between the deformation of the sensor and the decrease of the capacitance.
“We found that the height of the goose bump and the piloerection duration can be deduced by analysing obtained capacitance change trace,” explains KAIST researcher and co-author of the article, Young-Ho Cho.
While more work still needs to be done to correlate such physical measurements with emotional states, the work suggests that quantitatively monitoring goose bumps in real-time as an indicator of human physical or emotional status is possible, which could pave the way for personalised advertising, music streams or other services informed by direct access to the emotions of the end user.
"In the future, human emotions will be regarded like any typical biometric information, including body temperature or blood pressure," Cho claims.
The goose bump detector: a skin piloerection monitoring sensor conformally attached to the dorsal forearm of a subject in Cho's experiments (photo: Young-Ho Cho/KAIST)
Through use of micro-fabrication technology, Cho and colleagues built the sensor using a conductive polymer called PEDOT:PSS for the capacitors - a flexible alternative to brittle metallic conductive materials.
The capacitors were embedded in a silicon substrate via a multi-step spin-coating process, giving them a spiral shape and coplanar structure. This gave them high capacitive density and high deformability while remaining only 1.2 micrometres thick.
The silicon substrate, known as Ecoflex 0030, was selected due to its biocompatibility and high degree of flexibility relative to human skin. It is also highly stable with regard to heat and light, which allows the embedded polymer devices to maintain their performance in diverse conditions.
Future work includes scaling down the signal processing module and capacitance measurement system to be co-mounted on skin with the sensor.
Les Hunt
Editor
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