Trill Flex Is a New Bendable Touch Sensor From Bela

I think it’s safe to say that most microcontroller projects require some sort of button input, whether that be for simple functions like toggling modes or something more advanced like a MIDI piano keyboard. Traditionally, we use momentary push buttons or microswitches for those inputs. But capacitive touch sensor “buttons” offer a number of benefits. They’re thinner, less obtrusive, require a lighter touch, and they’re often more affordable. It’s fairly easy to integrate touch sensors into your custom PCBs, but if you need sensors that you can slap onto any project than the new Trill Flex touch sensor is for you.

Bela’s Trill capacitive touch sensors have been available for a while now in a variety of shapes and sizes, but this is the first that is flexible. Because the capacitive touch sensor is flexible, it can easily be applied to contoured surface in order to add inputs to a wide range of objects. Trill Flex is divided into two parts: the control board and the flexible capacitive touch sensor itself. The latter is printed onto a flexible PCB and is divided up into 30 individual “channels.” Each of those channels is like its own button and they can be used to trigger independent functions or can work together for something like a volume slider. You can also design your own flexible sensor PCBs if you want a different size or shape.

The Trill Flex “base” board works with the standard flexible sensor or your own custom sensors that you design with the help of the provided KiCAD template. The base board has its own built-in microcontroller to monitor the capacitive touch sensor. It then communicates with a Bela microcontroller board or any other development board (like an Arduino) via I2C. The I2C interface is through a standardized Grove connector, so you can use it with just about any board on the market. The Trill Flex base board handles the nitty gritty details of monitoring the flex sensor and simplified data on the sensor’s channel states are sent over I2C, which keeps your microcontroller code nice and clean. If you want to start using the new Trill Flex sensor, you can purchase the base board and touch sensor ribbon for £15 (about $21) right now on the Bela website.