The machine developed for the project Hugs of Coffee was designed as an interactive reward-based exchange interface that uses Kinect sensing to measure the time and type of interaction between two users. The initial idea, consists on rewarding the users depending on the level of physical interaction between them. In this case, after the interaction is made, a signal is sent to the Arduino that acts as a switch to activate the coffee machine. The first prototype of the machine was developed is as a compact box that could be transported to different places and that contained the different components inside. It contains a hacked domestic coffee machine, an iPad, Kinect and all the wiring that connects all these components to the Arduino board.

coffee prototype 1

Since the idea of the machine is to be technologically withdrawn, a user friendly interface is proposed to give instructions to the users about the usability of the machine. In this case, the welcome screen is activated when one user approaches the machine. It only changes to the next one, when 2 users stand in front of it. To give time to the Kinect to recognize the bodies and define their articulations, users are asked to wave their hands in front of the machine. Then, they are led to the final physical interaction which hugging for 10 seconds.


To measure the distance between bodies Kinect was programmed through Processing using the Simple Open NI library that allows mapping and measuring the different body articulations recognized by the Kinect as well as the center of mass of the bodies it detects. The UX interface was also implemented through Processing since the appearance of the different screens must be timed along with the interactions of the users. The rest of the system was managed through Arduino, which reacted when receiving the signal from Processing and activated the machine to start brewing the coffee.

layout tech

To control the coffee machine digitally, the physical switch used to activated had to be removed in order to connect the circuit of the machine to Arduino. To do this, a relay was connected in order to manage the difference in voltage from the power supply source of the machine and the one manageable by Arduino. When the coffee machine is activated, an LED acts as a physical indicator of it being on.

coffee diagram_bb2

Empathy Machine (Hugs of Coffee) is a project of IaaC, Institute for Advanced Architecture of Catalonia developed at Master in City and Technology in 2016 by:

Students: Mayra López

Faculty: Angel Muñoz, Tomás Diez & Mathilde Marengo

Assisted: Mariana Quintero