This sensor can turn any fabric into a fitness tracker
Harvard University researchers have developed a highly sensitive, soft capacitive sensor made of silicone and fabric that can turn any piece of clothing into a fitness tracker. The sensor moves and flexes with the human body which allows it to measure every movement accurately. Harvard professor Conor Walsh said the use of textiles in its construction would allow them to make 'smart' robotic apparel.
The science behind the making of the sensor
A thin sheet of silicone (a poorly conductive material) is placed between two layers of silver-plated, conductive fabric (a highly conductive material) to make a capacitive sensor. It records movements by measuring the change in capacitance (the ability to store an electric charge). For an accurate performance, the fabric is attached to silicone core on both sides with an additional layer of liquid silicone.
How does the sensor work?
When stretched, the length of elastic fabric increases while its thickness and width decrease, keeping the total area of the material and capacitance constant. However, on being stretched the sensor's conductive area increases, resulting in greater capacitance. This allows the sensor to detect any increase in capacitance within 30 milliseconds of strain application and physical changes in less than half a millimetre.
How does the future look?
The research team is positive that the textile technology could soon be used for motion capture applications in athletic clothing to track physical performance or in clinic devices to monitor patients. The sensors could prove to be useful to athletes, who can monitor their movements and learn from the feedback. Engineers could also use these sensors in developing robotic systems.
Level of sensitivity
The level of sensitivity of the sensor is so good that it can measure fine movements like a slight movement of a finger. Also, the material is light and flexible so that it doesn't obstruct any movement.