There is an academic conference called DIS (Designing Interactive Systems)
Submission deadline: February 28, 2020 (The submission system closes at 17:00 PST)
You need to produce evidence of a working prototype (videos / photos) and a four-page abstract describing the design. This is quite a lightweight submission compared with other academic conferences.
After submission you also have up to July 6-10 - the date of the conference - to polish the demo.