GSAP (Greensock Animation Platform) is a fast and robust animation library that can be used for tweening any numeric property of any object. It also supports timelines and sequencing. While it is not open source, it’s license is permissive enough for a lot of projects to use it for free.
Johnny-Five is a robotics and IoT programming framework based on the Firmata protocol. Johnny-Five programs can be written for Arduino (all models), Electric Imp, Beagle Bone, Intel Galileo & Edison, Linino One, Pinoccio, pcDuino3, Raspberry Pi, Spark Core, TI Launchpad and more!
DSP.js is a comprehensive digital signal processing library. It includes many functions for signal analysis and generation, including oscillators(sine, saw, square, triangle), window functions (Hann, Hamming, etc.), envelopes (ADSR), IIR filters (lowpass, highpass, bandpass, notch), FFT/DFT transforms, delays and reverb.
headtrackr is a library for real-time face tracking and head tracking. It tracks the position of a user’s head in relation to the computer screen, via a web camera and the WebRTC/getUserMedia standard.
Vizor is a content portal for virtual reality projects available in the browser. It is also a powerful dataflow programming toolset to aid in the creation and distribution of VR experiences (WebGL and WebVR).