VibraForge: A Scalable Prototyping Toolkit For Creating Spatialized Vibrotactile Feedback Systems

TL;DR

VibraForge addresses the need for scalable, expressive spatial vibrotactile feedback by introducing a chain-connection, modular hardware design with self-contained vibration units and a centralized control unit. It delivers up to $128$ actuators with low end-to-end latency (~$16$ ms) and high bandwidth ($ imes 200$ Hz) while maintaining usability via a GUI Editor and open-source tools. The paper validates the approach with technical evaluations and three case studies—phonemic display, VR fitness, and UAV teleoperation—plus a usability study showing a low onboarding barrier. Collectively, VibraForge expands the design space for tactile interfaces, enabling rapid prototyping of complex, body-worn haptic systems for diverse applications.

Abstract

Spatialized vibrotactile feedback systems deliver tactile information by placing multiple vibrotactile actuators on the body. As increasing numbers of actuators are required to adequately convey information in complicated applications, haptic designers find it difficult to create such systems due to limited scalability of existing toolkits. We propose VibraForge, an open-source vibrotactile toolkit that supports up to 128 vibrotactile actuators. Each actuator is encapsulated within a self-contained vibration unit and driven by its own microcontroller. By leveraging a chain-connection method, each unit receives independent vibration commands from a control unit, with fine-grained control over intensity and frequency. We also designed a GUI Editor to expedite the authoring of spatial vibrotactile patterns. Technical evaluation showed that vibration units reliably reproduced audio waveforms with low-latency and high-bandwidth data communication. Case studies of a phonemic tactile display, virtual reality fitness training, and drone teleoperation demonstrated the potential usage of VibraForge within different domains. A usability study with non-expert users highlighted the low technical barrier and customizability of the toolkit.

Figures (20)

• Figure 1: Depiction of the direct connection (left) and multi-layer connection (middle) methods commonly used in spatialized vibrotactile systems and our proposed solution (right), which uses a chain connection method.
• Figure 2: (Left) Exploded views of the small vibration unit for X-axis LRAs, including the cap, the PCB, the PCB mount, the enclosure, and the bottom ring. Z-axis LRAs shared most components except for the enclosure. (Right) Exploded view of the large vibration unit for VCAs with a similar structure. Note that the bottom ring was placed underneath the garment to attach the unit.
• Figure 3: The circuit schematics and PCB board designs of the vibration units.
• Figure 4: The control unit, which contained an ESP32 MCU, an extension board, chain connectors, and LiPo batteries.
• Figure 5: The multiple chain-connection method used within VibraForge, depicting the connections required for a given chain.