If you use it, please cite us.
Jiang, P., Burchell, A., & Pelli, D. G. (2021, December). EasyEyes aids online testing by emulating a wireless keyboard and tracking viewing distance. In PERCEPTION (Vol. 50, No. 1_ SUPPL, pp. 7-7). 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND: SAGE PUBLICATIONS LTD. 

@inproceedings{jiang2021easyeyes,
  title={EasyEyes aids online testing by emulating a wireless keyboard and tracking viewing distance},
  author={Jiang, Peiling and Burchell, Augustin and Pelli, Denis G},
  booktitle={PERCEPTION},
  volume={50},
  number={1\_ SUPPL},
  pages={7--7},
  year={2021},
  organization={SAGE PUBLICATIONS LTD 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND}
}

Programmers - Remote Calibrator package can build the step-by-step calibration panel at the start of the experiment with a few lines of code. This page runs in demo mode. In a real experiment, participants would only be allowed access to one step at a time. All the text, including the headline, the description, and the next-step button, can be customized. Learn more about this package at the GitHub and API playground pages.