FSR Matrix Sensors for Human-Computer Interaction

In a previous post I talked about a capacitive multi-touch solution that can work well for multi-touch computer control, where you don’t want or need a display as part of the multi-touch input surface.

Another alternative that provides even more expressive control is to use a Force Sensing Resistor (FSR) Matrix sensor which not only gives the x and y position of numerous touch points, but also gives a z parameter for how much force is being applied at each touch point. One company, Sensitronics (owned and run by the inventor of FSR sensors, Frank Eventoff), makes the raw matrix sensor sheet and they are happy to partner with other companies who will built the rest of the input device electronics, PC drivers and libraries. The materials used for FSR matrix sensors make them opaque, so this technology will work for trackpads, graphics tablets, etc, but not for displays. Sensitonics recently made available larger sensor sheets, moving beyond the smaller sizes (typically laptop trackpad size range) previously available.

However, Sensitronics has recently also been working on breakthrough clear materials, and can be contacted regarding this new innovation. Clear FSR matrix sensor sheet applied to a display will provide a very attractive alternative multi-touch display for many use cases.

Note that FSR sensors can also be produced as sensing strips, rings or individual buttons, however my primary interest has been in multi-touch x-y-z grids for gesture control of computers.

For anyone wanting to use an FSR matrix sensor in their project there is currently a drawback – input devices utilizing the technology are not widely available, and it is a significant amount of engineering work to develop the electronics, PC drivers and libraries to support a usable solution. One company I know of is producing a more complete FSR matrix solution – Sensible UI from Korea. Check out their ArduMT if you want a development plug in solution for PCs.

Sensible UI - ArduMT multi-touch input controller

Sensible UI - ArduMT multi-touch input controller