Notice boards play a vital role mostly in educational institutions. The events, occasions or any news, which has to be passed to the students, will be written on the notice boards present in every floor in the colleges or schools. The present system is like, a person will be told the news and he has to update this news on all the notice boards present in the college or school. This will be seen mostly during the examination seasons.
The time table or the schedule of the exams has to be given to the students. This will be done by writing the details on the notice boards. But this process consumes a lot time to update the news on all the notice boards and there may be chances that the person responsible may commit some mistakes or he may be absent sometimes. So, this may create disturbances and the entire schedule may be disturbed. To avoid all these, electronic Notice Board have been designed which completely eliminates the manual work.
Here we are using RS48. It is an alternative for RS-232 for long distance. RS-232 only up to 15m. but in MAX 485 up to 1500m limit. in addition we connect up to 32 devices. If your control system needs to receiving and sending data in the same time you must use full duplex transmission mode. It is possible (and in real world this is the most popular case) that control system first sends request message to ROV (e.g. get temperature) and than waits for the response. In this scenario, there is no possibility that control system and ROV sends data in the same time, so half duplex communication is sufficient. For full duplex communication you need 4 wires, for half duplex only 2 wires. MAX485 is providing half duplex mode. If you need to use full duplex you must use 2 units (or full duplex chip).
PC is interfaced to the transmitter section to type the data and transmit. The message can be transmitted to multi point receivers. At any time, the user can add or change the message according to his requirement. At the receiver side, the message will be displayed on the LCD display unit.
- Multiple transceiver application.
- Low power application.
- Long distance capability up to 1.5 kms
SOFTWARE AND HARDWARE TOOLS:
- Keil compiler