It may be true that we are living in an ever more connected world, but the lack of connections between digital devices in your home might make you think otherwise. Many of us have a number of Internet of Things (IoT) devices, and a different method for communicating with each — perhaps speech recognition for the smart speakers, a hub and an app for the light bulbs, and separate apps for the coffee maker and printer. This state of affairs has many of us pining for simplification.
That desire for simplicity has also been felt by a team of engineers at Bundeswehr University Munich. They have developed a smart desk platform, called ActPad, that is a single point of interaction for IoT devices — well, for IoT devices within the vicinity of your desk, anyway.
ActPad is a thin mat, approximately two feet by three feet in size, that is placed on the surface of a desk. 40 electrodes are distributed about the surface of the mat, with each being individually wired to a central circuit board. A Raspberry Pi 4 serves as a controlling unit to acquire sensing data, and to perform computations.
Users interact with ActPad through capacitive sensing by physically touching the electrodes. ActPad also includes connectors for object-to-sensor mappings. These connectors consist of flexible 3D printed cases, double sided tape, and a copper foil electrode connected to a wire. By attaching these connectors to otherwise uninstrumented objects, touches will be transmitted from the object to the ActPad electrodes.
Because each electrode is individually wired, it is possible to supply the system with some complex interaction types. Multiple electrodes can be touched, either simultaneously or in a meaningful sequence. Beyond explicit inputs of the sort already mentioned, implicit inputs are also possible — upon touching a particular series of objects based on a morning routine, a coffee maker could be activated, for example. The team implemented a Python-based graphical user interface on the Raspberry Pi to allow users to customize interaction commands and map them to actions.
The engineers first used the pad to control actions on their computer, e.g. web browser interactions, and playing music. They next used ActPad to control a smart power socket switch, which can be controlled over HTTP. This switch was used to control a number of other devices, such as lamps, coffee makers, and monitors. The coffee maker was controlled by moving a cup from one electrode to another, and the lamp was controlled by a specific touch sequence. The authors of the paper have not yet conducted user experience and usability testing to determine how ActPad will be received by real world users.
At present, the device operates through direct physical contact of objects to be controlled with the mat which limits the situations in which it can be applied. They are hoping for a future in which most IoT devices are touch aware by default, which would remove this restriction. Also, while the control unit has WiFi and Bluetooth connectivity to interact with many devices, it otherwise does not have a tight integration with any existing commercial smart home solutions, so it may be unable to communicate with many devices.