One group’s project is bringing a much more literal meaning to the term ‘mind game.’
First launched in 1946, Labyrinth is a skill game consisting of a box with a maze, holes, and a steel marble. The object of the game is to try to tilt the playfield to guide the marble to the end of the maze, without letting the ball fall into any of the holes. While versions of the game featured a suspended maze surface that rotates on two axes using a knob, other handheld versions have included an entirely closed transparent cover on top. However, none have ever been controlled by the human mind. That was, at least, until now.
As part of Autodesk’s neuroscience themed hackathon event, BrainiHack 2015, a team of Makers going by the name Blue GSD — Daniel Harari, Gal Weinstock, and Maxim Altshul — created their own iteration of the classic game, all powered through brainwaves. The contraption was entirely 3D-printed and based on the OpenBCI open-source platform (ATmega328P).
To start, the game’s movement was enabled through a pair of micro servo motors, each controlled with an Arduino Uno (ATmega328). Meanwhile, the mechanism was comprised of three nested frames that were anchored in various places to achieve two degrees of freedom – roll and pitch. Given the limited amount of time to complete the project, the motors and motor arms were all attached to the frame using zip ties, while some nuts and screws were employed to keep the frames in place.
For those who may not know, OpenBCI offers a GUI that lets users visualize and analyze data in a more efficient and easier manner. The interface provides time-domain and frequency-domain (FFT) graphs, as well as a map of the head with electrode activity. OpenBCI allowed the team to attach electrodes wherever they wanted, and carry out experiments with various methods and brain waves.
“Once the data is captured with OpenBCI, it is transferred to the computer for analysis, the computer runs a Processing program that computes the Fourier Transform of the signal over a defined interval of time, filters the spectrum to look at relevant frequencies and finds the most powerful frequency in the range,” the team writes. “If the peaked frequency is the one we are looking for, a command is sent to an Arduino board via serial port. The Arduino then controls the servos according to the command received.”
However, the problem with brain-reading technology is that it can be on the slower. Given the real-time nature of the Labyrinth game, any sort of delay can cause a lapse in judgement and the ball to fall through a hole. As a result, the team decided to simplify the game into a basic maze with two different signals to study — the left-right position toggle was controlled via Alpha waves, while up-down positioning driven by SSVEP. By combining both Alpha and SSVEP, the team was presented with two types of waves that were capable of control and anticipation, which provided them the ability to control the game with just one person.
As it turns out, the team who admits to having absolutely no background in neuroscience ended up winning the OpenBCI prize for the best project in the open-source category. Those interested can head over to its official page to read more. Meanwhile, the project’s files are available on Thingiverse so that Makers can download and create their own Labyrinth game.