Project Description

ChillFish is a breathing exercise disguised as a biofeedback game that assist children to calm down e.g., prior to bedtime. Designed in LEGO, the ChillFish controller works as a breath-based input device in which the child can control a virtual (puffer fish) avatar in an underwater world.


The ChillFish gameplay is based on an underwater 2D world, where the player character (a puffer fish) has to collect as many star fish a possible. The vertical position of the puffer fish is controlled by the child’s inhalation and exhalation through a physical LEGO fish controller. When the child breaths into the ChillFish LEGO controller, the virtual puffer fish moves towards the top of the screen and at the same time the puffer fish expands in size. The star fish are positioned so that in order to collect them all, the child has to apply a relaxed breathing pattern.

ChillFish is implemented in the Unity Game Engine, and the game controller is built in LEGO and designed as a fish to resemble the main (fish) character. A thermistor connected to an RFDuino is embedded into the LEGO fish (see Figure 2), which detect changes in temperature when the player breathes. The sensor values from the thermistor are smoothed and sent from the RFDuino to ChillFish via a Bluetooth 4.0 connection. The movement of the player character is determined by the changes in the incoming sensor values e.g. for each time the change in temperature is larger than a predetermined threshold, the player character moves either up or down, depending on whether cold air is inhaled through the controller or hot air is exhaled into it. By using the delta change in temperature instead of the absolute temperature ChillFish requires no calibration and are not affected by the room temperature.

The RFDuino placed inside the ChillFish LEGO controller uses a thermistor to gather breath data, which is then transmitted via a wireless Bluetooth 4.0 connection to the ChillFish game.

ChillFish version 2

More info to come..