Digital clock synchronization using IP with wireless fidelity

A clock in daily-life functions are very much, especially the highly visible usefulness as determination lecture schedules has started and finished. The problems that led to the digital clock is not always accurate, because devices used in the manufacture of digital clock cannot keep time accurately and digital clock run time without using an additional device such as RTC. This clock can also synchronize at the same time according to the time on the computer server for the elapsed time and time in the digital clock is always updated. There are two models, namely digital clock, Raspberry pi as a microcontroller master clock and ESP 8266 as a slave microcontroller clock. Master clock sends the command as a slave as publisher and subscriber will perform a given task, namely, synchronization time and turn the alarm on. The average time accuracy of the master clock for one week is 99.998% and its average deviation time is 1 second in one day, while the clock slave has an average accuracy rate for the week amounted to 99.918% and its average deviation time is 71.29 seconds in one day. During the 6 hours running time, slave clock will run into inaccuracies of up to 17.8 seconds, therefore the synchronization process will be conducted every 6 hours or 4 times a day to maintain its deviation no more than 20 seconds.