NIA / COCOMO
A plush-toy device that moves in sync with your favorite performer's heartbeat
- Finalist, TOKYO STARTUP GATEWAY 2024
- Finalist, Why-Me? (hosted by KBC, Keio University)
Overview
NIA / COCOMO is a plush-toy device that moves in sync with the heartbeat of a favorite performer. Development began under the name NIA, and the product was later renamed COCOMO. The plush breathes, vibrates in time with the heartbeat, and warms to body temperature, aiming to maximize the sense that your favorite performer is right there with you.
From consultation to concept
The project began with a consultation from idols and people in television: could we build a way for fans to feel closer to performers during streams and live shows? In the autumn of my first year of university I visited Oshikatsu EXPO, a trade fair for fan culture, and seeing the scale and heat of that market firsthand convinced me the request was worth answering. Shohei Nishida, who was driving the project with me, and I brought our impressions together, and the discussion arrived at the current form: a plush toy that shares a heartbeat.
NIA was originally implemented by Nishida as a smartphone app. When the idea came up of realizing it as a plush toy instead, I took sole charge of the hardware design and development.
The device I built
Heart-rate capture and transmission are handled by an ESP8266, and I designed the enclosure and mechanism in Autodesk Inventor. Breathing is reproduced by chest movement driven by a rack-and-pinion mechanism, the heartbeat by vibration synchronized to the pulse, and body warmth by heating. I put weight on what you can actually feel when you hug it.
CAD of the enclosure interior 
Design rendering of the device body The prototype device to be embedded in the plush toy
Raw sensor data capture screenWe also had streamers on platforms like YouTube in mind and designed with OBS integration in view. For example, I implemented a demo UI whose display changes with heart rate, using Python and OpenCV.
Technology that syncs with the stream
The most distinctive part of this project is the synchronization technology that ties the stream itself directly to the plush toy. If heart-rate data travels over a separate channel from the video, the two paths never transfer at the same speed, so a time lag is unavoidable. YouTube’s comment section, for example, appears 20 seconds to a minute behind the video.
So we developed a scheme that embeds the data into the streamed video itself, sends everything over a single channel, and has the plush process the video internally to extract the data. Because the video and the data always travel the same path, the system automatically tracks both stream delay and archive playback position, and the offset between the video and the plush’s behavior is zero in principle. The moment your favorite performer on screen is startled, the plush in your arms quickens its heartbeat at exactly the same time. This holds equally for live streams and for watching the archive afterward.
Recognition and presentations
At TOKYO STARTUP GATEWAY 2024, a business plan contest hosted by the Tokyo Metropolitan Government that the two of us entered, we were selected among the ten finalists. At Why-Me? (January 2025), a pitch contest hosted by KBC, Keio University’s officially recognized entrepreneurship club, we also took the stage as one of six finalist teams, where NIA was introduced as technology that connects people’s hearts and creates a sense of reassurance and bonds. In the PoC, an idol actually used the device, and the feedback was very positive.