First public presentation of teacher.js

Frederic Brodbeck and Daniel D. Hromada

Einstein Center Digital Future / Berlin University of the Arts

What is teacher.js ?

teacher.js is a web-based communication / teaching tool. Designed for being run on solar-powered devices outdoors it aims for keeping both bandwidth and power consumption low. For that reason it does not make use of video streaming but instead integrates a number of different modules for audio calls, chat, collaborative editing, code-streamed HTML/Javascript presentations and wikipedia browsing. The teacher and students clients communicate / synchronise via a light-weight event-based protocol. In comparison with BigBlueButton we observe significant decrease of amount of data transfered from the server in the scenario of a content-oriented lecture.

Why teacher.js ?

Outdoor Online Teaching

teaching != screen sharing

Can someone please tell me why teachers need to broadcast megabytes of video-signal when while it would be more efficient and comfortable to broadcast to student browsers few bytes containing a command (e.g. display slide) and its parameters (e.g. from "URL X") ?


Definition: Codecasting (shortened form of "code-broadcasting") is distribution and execution of program code snippets forwarded from the source (e.g. teacher) viewport to one or multiple target viewports (e.g. student browsers).

1 class :: 1 room :: 1 server

For those interested in a little demo, point another tab of Your browser to

teacher.js architecture

audio mixer (Janus audiobridge/WebRTC)

teacher.js 1.0 (available modules)

Shared notes (Etherpad-lite)

Chat (matrix/hydrogen)

Wikipedia module

Presentation module

a BigBlueButton/ teacher.js comparison

BBB / teacher.js summary

next steps

shared video-viewing (code-casting)

whiteboard (spacedeck)

collaborative reading

Summer Semester 2022 Online Gardening course

secure funding & create community

summa summarum

it is possible to have an online teaching toolkit running on a Raspberry Pi hardware

replacing video-streaming with code-casting paradigm leads to significant bandwidth reduction...

...and has many additional advantages (e.g. students can actually work with the source document)

the aim of teacher.js project is not to develop yet-another-videoconferencing-tool, but to provide a motivated teacher a minimalist yet modular & extensible toolkit containing everything he or she should need to do a good on-line course

links & references

Brodbeck & Hromada (2021) teacher.js extended abstract (Researchgate)

Hromada (2021) Three principles, 2 sub-principles and one magic wand for harm minimization and prevention of technological addiction in human children (accepted for publication Educational Innovations and Emerging Technologies)

Thanks for Your attention

@DigiEduBerlin (Twitter, Instagram)

Creative Commons CC-BY-NC-SA applies on all contents of this presentation