The Trill Sensors are made to interact with the world by using your hands. It tracks the finger movement very precisely by using capacitive touch sensors. Different types of these sensors are available for example a Bar, Ring or a Square which I am using on my Kalimba. The sensors are compatible with a wide range of different microcontrollers that support the so called I2C communication protocol.
This protocol provides a convenient method of passing messages to, and getting data from, a network of sensors and devices. It allows you to not only connect one sensor per input, but instead you can connect multiple devices to one controller and requires only two wires for the communication.
Every device must have a unique I2C address, especially when more devices are connected to the same bus. To initialize a trill sensor in Pure data there has to be given a sensor ID, the i2c bus that the sensor is connected, which device, the mode and the address of the sensor. (Bela, 2021)
After successful initializing the sensor we can read from it through r bela_trill object. By using the square sensor the incoming data is formatted as a list with the following items: number of touches, x axes, y axes, size.