PC Based Automated School Bell With Counter

Listing ID #961531

PC Based Automated School Bell With Counter gives bell after 45 min with interval of 30 min. It also keeps a track of time interval. This is the automated type of school/college bell, which controls through program written in ‘C’ language. The program is designed for total 8 periods. The circuit automatically rings bell every after 45 minutes for first four periods. Then it gives interval of 30 minutes. After interval, bell rings again, after every 45 minutes for remaining four periods. The time period of ringing the bell is set at 5 seconds. The time duration can be modified according to requirement by simple modifications in the program. In addition the counter is designed which counts the time in minutes and display is shown on two 7-segment display. Thus when first period is over, the display shows ‘45’ and so on for remaining period. For interval also, the display shows ‘30’. As stated earlier you can also modify the time periods by simple modifications in the program.
About the Circuit :
The interfacing circuit is shown in the diagram with PC’s parallel port. When program is executed, the program gives the message as: “This is the program of Automated School/College Bell with Counter. Press any key to continue…”
After some interval, program generate control signal at port-3. As port-3 is connected to clock-input of counter IC, it starts counting. The duration of clock pulse is set at 1minute in the program. After 45 minutes, counting stops and display shows ‘45’ on two 7-segment display, which is driven by counter ICs. At the same time program generate control signal at port-2. Transistor T1 drives opt isolator IC3. As a result TRIAC gets triggered and bell connected at its output rings. After this the control goes to port-4 which is connected to reset input of counter IC. As a result counter reset and display shows ‘00’ for very few seconds and again cycle repeats for next period. This procedure repeats for first four periods. Then it gives interval of 30 minutes. For this control signal generates as above but the duration is of 30 minutes and display shows ‘30’ on 7-segment display. After interval, the cycle again repeats for remaining four periods. When the program is in execution on screen, you can read messages as “Period 1 is going on”. When it is over the program gives message “Period 1 is over”. These messages are given for every period and interval also. Thus you are able to know what is going on.