Vibrotactile Stimulator
NodeMCU-based device controls eight vibration outputs.
Machine feedback typically happens via lights, video, or sound. Depending on the application, however, you might also want to explore using vibration as a feedback method, e.g. vibrotactile interface. HackyDev's vibrotactile stimulator provides a platform such an interface – or any other multi-output vibration application – controlling up to eight vibration stimulators with a NodeMCU board.
On startup, the device generates a “vtstim” Wi-Fi network, enabling you to log on with a smart device and navigate to the designated IP address to adjust settings. Options include modifying the on and off periods, vibration frequency, jitter and more. There’s also a mirror mode which can be set up to stimulate corresponding fingers on each hand.
Of course, hooking the stimulators up to fingers as an interface is only one option, as the device doesn’t list a designated use. Hopefully this will spark some new ideas, or facilitate old ones. Code is available via the project write-up for your usage and/or edification.
Hardware-wise, the device's simulators are each constructed with coil taken from a power relay, a permanent magnet, and a 3D-printed housing and spring. Each is controlled with the help of a MOSFET, allowing the NodeMCU setup to satisfy the devcie's current requirements. While the stimulators are a clever design, HackyDev notes that they’re a bit labor-intensive, and would instead recommend using off-the-shelf audio exciter units.