Big Screen II app for iPhone and iPad

Big Screen II transmits, and optionally records, live video from the camera to a second screen connected by AirPlay. The controls are not mirrored to the second screen or the recording.

App includes a link to instructions for a DIY document camera for videoconferencing lectures and office hours from home.

- Front or back camera
- Landscape or portrait orientation
- Records video and audio
- Supports camera zooming
- Tap to focus; Double tap to autofocus
- Adjust exposure by sliding after focus
- Triple tap suppresses Airplay warning
- Can use as a document or demo camera
- Video recording: 1280 x 720 px with HEVC (if supported) or H.264 compression

Big Screen II is part of a digital whiteboard developed in the Hines Lab in the Dept. of Chemistry and Chemical Biology at Cornell University. The lecturer faces the classroom and writes on a sheet of illuminated glass with a fluorescent pen. The front-facing camera on the iPad behind the glass captures a video of the lecturer and his/her drawings and writing. Because the front camera flips the image horizontally, the lecturer’s writing is not reversed. Unlike a traditional white board, the lecturer cannot obstruct the writing. A full description of the whiteboard and instructions for its construction are given in E. S. Skibinski, W. J. I. DeBenedetti, A. G. Ortoll-Bloch, and M. A. Hines, “A Blackboard for the 21st Century: An Inexpensive Light Board Projection System for Classroom Use,” J. Chem. Educ. 92, 1754 (2015).

Instructions for constructing the digital whiteboard can be downloaded using a link provided in the app or from the supplemental information of the J. Chem. Educ. article listed above.

A big thanks goes to Kirby Turner of White Peak Software, Inc. who wrote the original Big Screen and who graciously shared his source code. Big Screen II is a de novo rewrite of Big Screen with added videorecording capability. All bugs are mine.

Development of the digital whiteboard was supported by the National Science Foundation under Award CHE-1708025.