EST is the acronym of "experience sampling timer", it takes as parameters an URL of a link to display in a new browser tab (e.g., the questionnaire for an experience sampling experiment), and the number of data gathering points to sound the alarm semi-randomly, in the next X minutes.
hence, for 6 data gatherings randomly (but at roughly even intervals, within +/-5 minutes) in the next 75 minutes, the URL can be as follows:
https://lprisan.github.io/est/?times=6&totalmin=75&devmin=5&url=http...(URL encoded address)