Set the RGB values for Blink(1)/Digispark+RGB according to the time to the next meeting in your Lotus Notes Calendar. Moving from green at 20min (or more) to red in the last 5 mins before a meeting. The light turns blue for the duration of the meeting.

NextCalEntry.java

package uk.me.hardill.notes;

/**
 * NextCalEntry
 * 
 * Sets the RGB values for Blink(1)/Digispark+RGB
 * according to the time to the next meeting in 
 * your Lotus Notes Calendar
 * 
 * This should be run with the JRE that ships with
 * Lotus notes as it has the required classes on 
 * classpath and have Lotus notes directory on 
 * library path e.g.
 * LD_LIBRARY_PATH=/opt/ibm/lotus/notes
 * /opt/ibm/lotus/notes/jvm/bin/java NextCalEntry -d
 */

import java.text.SimpleDateFormat;
import java.util.Date;

import lotus.domino.Database;
import lotus.domino.DateTime;
import lotus.domino.DbDirectory;
import lotus.domino.Document;
import lotus.domino.NotesFactory;
import lotus.domino.NotesThread;
import lotus.domino.Session;
import lotus.domino.View;
import lotus.domino.ViewEntry;
import lotus.domino.ViewEntryCollection;

public class NextCalEntry extends NotesThread {

   static SimpleDateFormat dateFormat = new SimpleDateFormat(
         "dd/MM/yy H:m:s z");

   static int rgb[] = { 0, 200, 0 };

   static int pollInterval = 300;
   static boolean mqtt = false;
   static String topic = "";
   static boolean digi = true;

   public static void main(String argv[]) {

      for (int i = 0; i < argv.length; i++) {
         if (argv[i].equals("-b")) {

         } else if (argv[i].equals("-d")) {

         } else if (argv[i].equals("-t")) {
            mqtt = true;
            topic = argv[++i];
         }
      }

      NextCalEntry nextCalEntry = new NextCalEntry();
      nextCalEntry.start();
   }

   public void runNotes() {
      try {
         Session s = NotesFactory.createSession();

         DbDirectory dir = s.getDbDirectory(null);
         Database db = dir.getFirstDatabase(DbDirectory.DATABASE);

         db = dir.openMailDatabase();

         if (db.isOpen() == false)
            db.open();

         db = dir.openMailDatabase();
         View calendarView = db.getView("($Calendar)");

         DateTime sdt = s.createDateTime("today");
         sdt.setNow();
         DateTime edt = s.createDateTime("today");
         edt.setNow();
         edt.adjustDay(+1);

         ViewEntryCollection vec = calendarView.getAllEntries();

         ViewEntry entry = vec.getFirstEntry();

         int offset = 3600;
         boolean poisonPill = false;
         while (entry != null) {
            Document caldoc = entry.getDocument();
            String sub = caldoc.getItemValueString("Subject");
            DateTime startDate = null;
            try {
               startDate = (DateTime) caldoc.getItemValueDateTimeArray(
                     "StartDate").firstElement();

            } catch (Exception e) {

            }

            if (startDate != null) {

               for (int i = 0; i < caldoc.getItemValueDateTimeArray(
                     "StartDateTime").size(); i++) {

                  int st = sdt.timeDifference((DateTime) caldoc
                        .getItemValueDateTimeArray("StartDateTime")
                        .get(i));
                  int en = edt.timeDifference((DateTime) caldoc
                        .getItemValueDateTimeArray("EndDateTime")
                        .get(i));

                  Date start = dateFormat.parse(caldoc
                        .getItemValueDateTimeArray("StartDateTime")
                        .get(i).toString());
                  Date end = dateFormat.parse(caldoc
                        .getItemValueDateTimeArray("EndDateTime")
                        .get(i).toString());
                  Date now = new Date();

                  if ((st <= 0) & (en >= 0)) {
                     if ((-1 * st) < offset) {
                        offset = (-1 * st);
                     }

                  } else if (now.after(start) && now.before(end)) {
                     offset = -1;
                     poisonPill = true;
                     break;
                  }
               }
            }
            if (poisonPill) {
               break;
            }
            entry = vec.getNextEntry();
         }

         if (offset > 0 && offset <= 300) {
            // red
            rgb[0] = 20;
            rgb[1] = 0;
            rgb[2] = 0;
         } else if (offset > 300 && offset <= 600) {
            // redish
            rgb[0] = 15;
            rgb[1] = 5;
            rgb[2] = 0;
         } else if (offset > 600 && offset <= 900) {
            // greenish/redish
            rgb[0] = 10;
            rgb[1] = 10;
            rgb[2] = 0;
         } else if (offset > 900 && offset <= 1200) {
            // greenish
            rgb[0] = 5;
            rgb[1] = 15;
            rgb[2] = 0;
         } else if (offset == -1) {
            // blue
            rgb[0] = 0;
            rgb[1] = 0;
            rgb[2] = 20;
         } else {
            // green
            rgb[0] = 0;
            rgb[1] = 20;
            rgb[2] = 0;
         }

         if (mqtt) {
            // TODO
            // connect to broker and publish
         } else {
            Runtime runtime = Runtime.getRuntime();
            String cmd[];
            if (digi) {
               System.out.println(rgb[0] + " " + rgb[1] + " " + rgb[2]);
               cmd = new String[4];
               cmd[0] = "DigiRGB.py";
               cmd[1] = rgb[0] + "";
               cmd[2] = rgb[1] + "";
               cmd[3] = rgb[2] + "";
            } else {
               System.out.println(rgb[0] + "," + rgb[1] + "," + rgb[2]);
               cmd = new String[3];
               cmd[0] = "blink1-tool";
               cmd[1] = "--rgb";
               cmd[2] = rgb[0] + "," + rgb[1] + "," + rgb[2];
            }
            Process proc = runtime.exec(cmd);
            proc.waitFor();
         }

      } catch (Exception e) {
         e.printStackTrace();
      }
   }
}