The Sensible Watch Puts Touch-Sensing Capability on the Strap

Smartwatches are very convenient devices, but they aren't perfect. Their touchscreens suffer from the same problem as all touchscreens: they force the user to put their finger over the thing they're looking at. But that problem is especially severe because a smartwatch's touchscreen is so small. Smartwatch touchscreens are difficult enough for people with normal dexterity to operate, and that becomes downright impossible for many people with disabilities. To increase accessibility, Josh Joy designed the Sensible Watch with a touch-sensitive strap that people can manipulate in unconventional ways.

People with physical disabilities often find alternative means of interacting with their devices, such as by using their chin or an elbow to push a button. The touchscreens on typical smartwatches don't accommodate that, because the touch area is too small. But it isn't possible to make the touchscreens larger without making the device cumbersome and unwieldy. Joy's solution here is a clever one, because it takes advantage of the additional surface area provided by the band. That added touch-sensitive area is easier to interact with and makes the smartwatch more accessible to people with certain disabilities.

In an ideal world, existing consumer smartwatches would get touch straps to improve accessibility. But that hasn't happened, so Joy is leading the charge by building a prototype. This prototype won't match the capability of consumer smartwatches, but it does prove the concept. Joy has made progress on the physical prototype, made with a Seeed Studio XIAO ESP32-S3 development board and a small OLED screen, but it is far from complete. Future prototypes will require custom hardware to fit into the practical size constraints that a smartwatch requires.

As Joy points out in his write-up, this will benefit from a hybrid touch sensor that combines elements of resistive and capacitive systems. Resistive systems require a lot of physical force and have very low sensitive, but capacitive systems only work with conductive objects like a stylus or skin — a prostheses may not trigger them. A hybrid touch sensing strap would always work and would allow for higher sensitivity when capacitive sensing is viable.

The Sensible Watch would accept gesture input through the touch strap. It would be possible to tailor those gestures to suit the individual user's abilities, letting them take advantage of the convenience offered by smartwatches.