What is a Real time controller (RTC)?
This is a project on RTC controller which is a circuit that controls operation of a device based on the ON and OFF timing given by the user. Read this project to know how RTC keeps track of the current timing, if the specified timing of any individual device is reached how it is switched ON\OFF using a relay? Here we will use 4 relays to control the operation of 4 devices.
Working of a real time controller
Power supply
As we switch on the power supply,230 V from A.C. mains comes to the step down Transformer where converts it into 12 V A.C.
Now 12 V A.C. is supplied to bridge rectifier where it converts A.C. into D.C. with some ripple present in it, to remove these ripples a filter is provided & that is given to regulator I.C. 7805 from where we get 5 V constant D.C. output, which is applied to other I.C's as micro-controller, LCD, LED, RTC, KEYPAD etc.
Modes of operations
When supply is connected to all the device, LCD displays the 3 modes:-
1>EDIT SETTING
2>SET MODE
3>STANDBY
Our operation starts from mode 1. As we press 1 from our keypad it enters into edit setting mode & ask for the setting number as we can enter 100(0-99) settings at a time. After entering the setting number we have to enter the on-off time of all the 4(0-3) devices.
When all settings have been saved then mode 2 should be operated by pressing the key 2 from keypad.Then it asks which setting should be applied. After entering the setting number that setting will be applied.
After that mode 3 operates by pressing 3 from keypad which is standby mode. In standby mode LCD displays the setting number, actual time with day & on-off time of all the devices.
Now, when the on time of any device matches with the actual time the interrupt generates in micro-controller from where the relay has been operated, & the device ON. Similarly all on times were getting compared with actual time so that interrupt has been generated & devices should be ON. Meanwhile the offtime of all the devices were being compared with real time so as to generate interrupt for making the device OFF.Example based on operation
Suppose the real time is 10:10:10. Now we pressed key 1 from keypad so as to enter in edit setting mode where we enter the setting number 00 & on-off time of all the devices as:
Device 0: 10:10:30
10:11:00
Device 1: 10:10:50
10:11:50
Device 2: 10:11:00
10:12:00
Device 3: 10:10:35
10:13:00
After entering the details key 2 should be pressed so as to apply the setting 00. Then it should be left on standby mode by pressing key 3 from keypad, which is for standby operation.
Now when real time increases and reaches upto 10:10:30 the on time of device 0 matches with real time. Thus interrupt generates in micro-controller & the device 0 is made ON. Now when time reaches 10:10:35
Again the on time matches with real time, thus device 3 is made ON. The real time increases and thus all the entered time getting compared with real time so that the devices should on-off automatically.
Thus at 10:10:50 device 1 is also ON & after reaching 10:11:00 device 2 is also made ON but meanwhile device 0 is made OFF because it's off time is 10:11:00.
Similarly at 10:11:50 device 1 gets OFF, at 10:12:00 device 2 gets OFF & finally at 10:13:00 device 3 also gets OFF automatically. Conclusion
Thus, our aim completes here of saving electricity and making efficient use whenever and wherever it is necessary.
Hello kamlesh kumar,
It is very important information and will use the Eletrical and Electronics students use while doing their project or thesis work. Also helpful for exams and their knowledge. Nice work.
Enjoy.