Knife Game with DC Motor HAT and Solenoids

This three-day experiment was a mixed reality application of the knife game (, demonstrating the impact of visual & audio perception on tactile perception.

The user puts their left hand’s index finger inside the MDF case, and the experience starts. On screen, the user can see an image of a virtual hand, with a virtual knife stabbing to the left and right of the virtual index finger. This animation is accompanied by an audible “tock…tock…tock”, together with slight vibrations felt by the physical hand. Suddenly, the knife on the screen stabs into the virtual finger, releasing virtual blood. At the same time the user feels a “stab” on the physical finger… The combination of visual and physical touch points creates a feeling of vulnerability.

The application was built using Raspberry Pi, a Stepper & DC Motor HAT, three solenoids, Spacebrew, Unity 2017.3.0f3, Python 2.7 (NOT 3) and the Adafruit Motor HAT driver.

Detailed documentation (with code snippets) here: