This app is developed for using the innovative, low-cost and pedagogy-embedded Mobile Logger designed by YEUNG Yau Yuen with the following functions:

(1) It can (a) manually or automatically (even in sleeping mode for overnight operation) record data from the mobile logger and (b) control the mobile logger by the buttons or menu at the bottom of this App. The leftmost one is for the choice of sensor while the rightmost one is the action to take. Click the middle button once to take a measurement but if you make a long click, it will toggle between Automatic or manual Measure mode.

(2) You may (a) calibrate the sensors (if necessary and you should read the hints below the picture or Help), (b) edit the data (either insert comments with a prefix # or delete wrong data), (c) add GPS data which consist of latitude (Lat), longitude (Lon), altitude (Alt) and speed and (d) take photos. Before adding GPS data, you need to enable the GPS device (if available in your smart phone or tablet) by checking its status. Under the Automatic Measure mode, the GPS data will be automatically stamped into the log record immediately after each automatic measurement.

(3) At the upper right corner menu, you may (a) plot graphs (with zooming of scales) for your recorded data, (b) draw Google maps (if GPS data recorded), (c) recover old data, (d) preview files, (e) save and (f) share data and graphs/photos. The data recorded by this logger is stored in a file with an extension of .log which includes system commands (as indicated with a leading # sign) or data (as indicated with a leading clock time in the format of hh:mm:ss> and given with the usual symbols and units for the data) while the exported graph data (.txt) will get rid of all those commands and comments (with time given in seconds) for further data analysis by any spreadsheet programme. Remember not to delete or modify the system-generated comments, especially the first line and those with date information. There are some sample data files on air pressure (e.g. hato_airpressure.log for typhoon Hato recorded during 22-23 August 2017) or PM2.5 available to plot graphs or draw Google maps (gps_*.log with GPS data). You may use or just look at them by selecting the Open item in the right top menu.

(4) If there are many data recorded for plotting graphs or drawing Google maps, you may take average (⊕ encircled + sign) of them over a given period of time for graphs (usually around 30-1000s) or a given distance of space for Google maps (usually within 20-500m).

(5) In case of accidental loss of Bluetooth connection, you can try to re-connect it (usually a few attempts needed). If you close and re-start the App, the old data may usually be recovered.

(6) By connecting the mobile logger to the App, you can easily turn it into an IoT (Internet of Things) device by enabling the Auto Upload function for automatically sharing data in a designated webserver. You remotely control the device and get its data through the Internet.

(7) Even without connection to any mobile logger, you may still be able to use the built-in sensors of your mobile device to collect data.