Google's Open Source Vibrotactile Haptic Platform Offers Feedback and Sensing in One
Released under the permissive Apache 2.0 license, this Arduino-compatible platform makes haptic feedback and sensing easy.
Google Research engineers have developed a vibrotactile haptics platform, designed to provide feedback in wearable electronics systems — and have released the design under an open source license.
"We develop[ed] a low-power miniature electronics board that can drive up to 12 independent channels of haptic signals with arbitrary waveforms," Google Research hardware engineer Arten Dementyev explauns. "The VHP [Vibrotactile Haptic Platform] electronics board can be battery-powered, and integrated into wearable devices and small gadgets. It allows all-day wear, has low latency, battery life between 3 and 25 hours, and can run 12 actuators simultaneously. We show that VHP can be used in bracelet, sleeve, and phone-case form factors."
The system is built around a Nordic nRF52840 system-on-chip running a firmware designed to be Arduino compatible. The haptic actuators — up to 12 per board - are triggered by signals transmitted over Bluetooth Low Energy (BLE), USB, or serial, or by on-board sensors including a microphone and an accelerometer.
Cleverly, the haptic actuators themselves are turned into sensors - measuring skin contact and checking to see if the wearable is properly in contact with the wearer, in order to provide consistent control over simulated feedback.
The work isn't just theoretical, either: The team has already used the platform to build an audio-to-tactile-feedback device designed to assist with the task of lip-reading. "One of the developers who employs lip-reading in daily life wore the bracelet daily for several months and found it to give better information to facilitate lip-reading than previous devices," Dementyev says, "allowing improved understanding of lip-reading visemes with the bracelet versus lip-reading alone. In the future, we plan to conduct full-scale experiments with multiple users wearing the device for an extended time."
A second implementation of the technology saw eight voice coils added to a smartphone case that were able to work as both inputs — the system sensing which of the coils were being touched at any given time — and as haptic feedback, providing richer notifications and enhancing the effects of entertainment including games and movies. Battery life for the platform, meanwhile, was measured between three and 25 hours.
"We hope that others can utilize the platform to build a diverse set of applications," says Dementyev. "We hope that with this platform, we can help democratize the use of haptics and inspire a more widespread use of tactile devices."
More information on the project is available on the Google Research blog, and in the Proceedings of the 34th Annual ACM Symposium on User Interface Software and Technology (UIST '21) where the paper is available under open-access terms. The source code and hardware design files for the audio-to-tactile bracelet, meanwhile, have been published to GitHub under the permissive Apache 2.0 license.
