- A 2009 Swedish project (Chalmers University + t2i.se) demonstrated a multi-pointer capacitive input device and keyboard called “DGTS,” predating Google’s similar efforts; two demo videos were linked.  
- The hardware used Analog Devices’ AD7147 capacitance-to-digital converter (CDC) with 12 analog channels, extended to 96 sensors via 8-channel analog multiplexers.  
- A full technical paper describing the system is available at https://link.springer.com/content/pdf/10.1007%2F978-3-642-03658-3_30.pdf.