An alarm clock is a clock that indicates a pre-set time by producing sound at that time. This functionality of digital clock is used to awaken people or remind them [[wysiwyg_imageupload::]]of something. This circuit is an extension to the digital clock with time setting option. Here an extra switch is provided to set the alarm. While the alarm is set, the clock time does not stop and runs in the background. The project is built around the 8051 microcontroller (AT89C51). The option to set alarm is provided by providing an extra switch S5, with the microcontoller At89C51, which is made active low.Whenever S5 is pressed, the time display goes off and only 1st segment is activated. But the clock time still runs in the background. In this mode, a segment can be selected in cyclic order by pressing S2. After selecting the desired segment, its value can be changed by using S3. Once the digits and hence the alarm is set, S4 is pressed to start the clock again. As soon as the set alarm time is reached, a buzzer gets signal from the microcontroller thus producing sound.
Digital Clock with time set option using seven segment and 8051 microcontroller
This digital clock not only displays time (on four seven segment displays) but also provides the user an option to set the time. For this the user has to first press [[wysiwyg_imageupload::]]the reset switch after which he/she can select and set a particular digit by incrementing its value. To run the clock with the set time, the user needs to press the start button. The seven segment and switches are interfaced with microcontroller AT89C51. This idea to provide option for setting time can be implemented in conjunction with the digital clock circuit. The control options for time setting are provided by means of tactile switches which are made active low. This circuit uses four such switches. As soon as S1 is pressed, the running clock stops and it goes into the reset mode where the first segment is activated. The segment to be set can be selected in cyclic order each time S2 is pressed. After selecting the desired segment, its value can be changed by using S3.
Simple Digital clock using 8051 microcontroller (AT89C51)
A digital clock is one that displays time digitally. The circuit explained here displays time with two ‘minutes’ digits and two ‘seconds’ digits on four seven [[wysiwyg_imageupload::]]segment displays. The seven segment and switches are interfaced with 8051 microcontroller AT89C51. This circuit can be used in cars, houses, offices etc. As soon as the Vcc supply is provided to this circuit, the clock starts from 00:00. The time is displayed on four seven segments (in common anode configuration) by using the concept of multiplexing. This is achieved by using timer interrupt (Timer0) of AT89C51 which is configured to refresh seven segments. The segments are refreshed many times in a second for simultaneous display. The clock runs with a delay of exactly one second. Timer1 has been used to produce a time delay of one second. The data pins (a–h) of all the segments are interconnected and receive signal from port P2 of the microcontroller. The control or enable pins (common anode) are connected to pins 1-4 of port P1 (P1^0 – P1^3).
GPS Clock Using Arduino
GPS is a common device which is used in many electronics applications like Vehicle Tracking System, Soldier Tracking System, Traffic Navigation and Surveillance System and many other systems. The main aim of the project is to get accurate times while using GPS Clock. GPS clock is a Universal Clock Which is mostly used at Railways Stations, Bus Stands and Airports. It is widely used for Military purposes too. In this project we are using Arduino pro mini for GPS updated clock… Arduino pro mini is an ATmega168 based microcontroller board, which is small in size and can be fitted on bread board easily.