Graphene membranes of only 1 atom thick are the most flexible impermeable membranes known to mankind. As a consequence, they are extremely sensitive to pressure changes. Compared to conventional pressure sensors in smartphones, graphene can be up to 10-100 times more sensitive due to its high flexibility and low membrane tension. Despite its thinness, it has high mechanical strength and gas impermeability. In this demonstrator, a pressure sensor consisting of 10,000 graphene membranes in parallel on a silicon chip of 1x1 mm2 is used to detect very small changes in pressure in a room, that are caused by the opening of a door. When the pressure in the room changes, the membranes are slightly deflected, which causes a capacitance change in the sensors. Due to this capacitance change several electrons per membrane flow onto the graphene, which is detected by a battery powered capacitance-to-digital converter chip and Arduino.
Presence detection in buildings is important for energy saving, indoor navigation and intruder alarms, however sensitivity of current pressure sensors is insufficient to realize it. The high sensitivity of a graphene capacitive pressure sensor, potentially complemented by other presence detection sensors like infrared, ultrasound and Bluetooth, can improve the energy consumption, activity monitoring and safety in the house of the future. User experience is improved by personalized music, climate control, and lighting themes that follow the user.