To read a binary watch, add the numerical values assigned to each of the lit diodes on the watch, and then add them together. Watches usually have three rows of diodes, one corresponding with hours, one with minutes and one with seconds.
For example, if the hour lights corresponding with eight and one are lit, then the time according to the binary watch is 9:00. If the minutes corresponding to 32, 16 and two are lit, then it is 50 minutes past the hour. Some binary watches also have a date mode, in which the hour diodes correspond with the month, the minute diodes with the day and the second diodes with the year.