PHASE ZERO
The Problem
When I moved to Eindhoven in 2019, I really missed having a piano in my tiny 10-square-meter room. I obviously couldn’t fit my parents’ upright piano, so I explored alternatives. The differences were vast—sound quality, design, price, interface, keys, materials, and portability. Even the premium models often felt cheap, and finding the right one was a journey. Ultimately, a choice was made; the Nord Electro 6HP. However, with my bands demanding lighter, faster and more responsive electric piano sounds, a desire for a lighter keybed started to form. The following question rose:
“What if I could adjust the feel of my keyboard and tailor it to match each sound?”
PHASE ONE
Researching piano’s and keyboards
Piano’s and keyboards come in all sorts and kinds. What originally started with the ‘arpicimbaloa’ (harpsichord) from Christofori in 1700, resulted into a large array of keyboard-instruments, all serving a different purpose. Just like fashion, piano and keyboard players will have their preference per instrument or use these instruments as tools to create the sounds they strive. I.e., keyboards and stage piano’s try to mimic as much sounds and interface elements from different instruments (grand piano, organ, rhodes, synthesizer).
Current research into haptic force feedback for keyboards and pianos reveals no commercial products with integrated haptic keys to modify key touch perception. However, studies like the MIKEY project and research by Timmermans explore creating realistic feedback and dynamic simulations. Timmermans developed a haptic piano key with custom actuators and sensors to replicate the feel of a grand piano. Other efforts, like Supakkul’s use of Stanford’s Hapkits, also investigate haptic feedback. Commercially, features like Nord’s “Dynamic Curve” and “polyphonic aftertouch” offer limited key feel adjustments.
To fully understand all elements of keyboards, piano’s, their feel and haptic implementation a fundemantal understanding of these topics was needed. This included a deep-dive in the history of piano’s, their mechanical working, the difference in keybeds, key sizes and instrument types.
PHASE TWO
Exploration; haptics, sketching, mechanics
Keybeds from manufacturers like Fatar are designed to mimic the feel of original instruments, such as grand pianos’ hammer-action keys and organs’ waterfall keys, while maintaining a portable form factor. However, these keybeds cannot dynamically change their feel or weight. Haptic force feedback offers a solution by using actuators to provide counterforce, replicating the sensation of weight or resistance. For this project, GB36-2 haptic motors and FEELIX software were used to design the haptic force feedback curves, enabling a more versatile and responsive keybed experience.
To implement this technology within the design space of keyboards and keybeds, a linear approach is needed. Based on several research and linear actuation mechanism an initial design was iterated. This sketch was then translated into a 3D-design to test limitations, issues and act as design research artefact.
The execution of this sketch to a 3D-printed prototype brought many issues and complexities to the surface., helping to shape the problem statement and discover possible solutions.
PHASE THREE
Iterative prototyping; an explorative approach
Following the initial prototype, multiple iterations were developed using a modular and explorative approach. This sandbox environment allowed for extensive testing and refinement of individual components. Each iteration was first designed in a 3D environment using Cinema 4D, complete with dynamic simulations. The designs were then optimized for 3D printing and fabricated with PETG to ensure material stability and strength.
The second iteration of haptic keys, dubbed The Overcomplicated One, aimed to minimize plastic contact for a high-end immersive experience. Inspired by JON-A-TRON’s linear motion concept (2017), I developed a rotational freedom mechanism with Feelix. The first version, The Tall One, used a hinge mechanism to create linear motion but still involved plastic friction. The Overcomplicated One eliminated plastic parts by using steel rods and bearings, but its complexity led to poor interaction. Ultimately, The Tall One’s simpler approach proved more functional, highlighting the importance of straightforward mechanical design.
The Considered Final One embraced a “back to the basics” approach based on the learnings from the Tall One. This simplified design minimized errors and allowed for effective motor mappings to simulate light, medium, and heavy key resistance. Although this implementation does not repect the limitations and linear approach needed for a haptic implementation in keyboards, it opened up explorative testing opportunities in a simple manner.
A push sensor was add to map force to MIDI CC values, creating two mappings: pitch-range and velocity. In pitch-range, more force raised the note, creating an arpeggio effect. In velocity, more force increased loudness, mimicking a piano’s hammer action. This design also enabled an “aftertouch” function, adding further versatility. The required force by the user was less when the motor mapping was weak, and stronger when the motor mapping was mapped at a heavy setting.
PHASE FOUR
Learnings & Business Opportunities
The Haptic Keys project has commercial potential but faces significant challenges. Implementing haptics in an 88-key keyboard is costly and impractical, highlighting the need for more efficient solutions. However, this research is an important first step towards affordable, seamless, and reliable haptic keyboards. The final prototype successfully demonstrated how haptics can enhance MIDI interactions, with heavier haptics allowing easier access to high notes and the slide sensor offering new musical possibilities. These innovations could inspire new products and ways for pianists and keyboard players to create music, indicating promising business opportunities with further development. The haptic implementation could improve the overall play ability and useability of keyboard instruments, and enable an “one-for-all” instrument system.
