A PROJECT PRESENTATION ONCompleted By: Project Guide:Shaikh Abul Quais (2449) Prof. SAJID NAEEMShaikh Faizan (2450) M.Sc-II(Electronics) DEPARTMENT OF ELECTRONIC SCINECE AKI’S POONA COLLEGE OF ARTS, SCIENCE & COMMERCE CAMP, PUNE-01
INTRODUCTION Now a day, because of the many companies coming up, there are great needs for advertisements. Making banners every time is a very time- and money- consuming task. Using a reprogrammable microcontroller along with an LCD of appropriate size solves the problem to a huge extent. This system can be used on roads where huge banners are put up. Along with this system that I have designed and build consists of an extra added feature announcement. Thus, the whole system can be used in places like railway station, railways, bus stops, buses, hospitals, roads, banking, colleges & schools etc. This system can not only display the message but also announce the message through the speaker. If display is not working then speaker is there to announce the message and if there is problem in the voice processing unit or speaker then the LCD is there to display the message. This is a very useful facility in this system. Therefore the “Rolling Display with Announcement System” system is very useful
AIM & OBJECTIVESAIM: The aim of this project is to develop microcontroller based Rolling Display with Announcement System.OBJECTIVES: To study the 8 bit AT89S52 microcontroller. To study the recording IC APR9600. To design the interfacing of recording IC APR9600 with AT89S52. To design the interfacing circuit of LCD to 8051 microcontroller. To develop the assembly language code for interfacing of LCD and IC APR9600 to 8051 microcontroller. To design rolling display with announcement system by using microcontroller 89S52 and APR9600 recording IC.
CONTENTS OF BLOCK DIAGRAM POWER SUPPLY MICROCONTROLLER VOICE PROCESSING UNIT(APR9600) DISPLAY SPEAKER
1. POWER SUPPLYTRANSFORMER RECTIFIER FILTER REGULATOR LOAD
2. MICROCONTROLLERMicrocontroller has: CPU (microprocessor) RAM ROM I/O ports Timer ADC and other peripherals
History of the 8051 In 1981, Intel Corporation introduced an 8-bit microcontroller called the 8051. This microcontroller had 128 bytes of RAM, 4K bytes of on-chip ROM, two timers, one serial port, and four ports (each 8-bits wide) all on a single chip. The 8051 is an 8-bit processor, meaning that the CPU can work on only 8 bits of data at a time. Data larger than 8 bits has to be broken into 8-bit pieces to be processed by the CPU.
The 8051 has a total of four I/O ports, each 8 bits wide. Although the 8051 can have a maximum of 64K bytes of on-chip ROM, many manufacturers have put only 4K bytes on the chip. The 8051 became widely popular after Intel allowed other manufacturers to make and market any flavors of the 8051 they please with the condition that they remain code-compatible with the 8051. This has led to many versions of the 8051 with different speeds and amounts of on-chip ROM marketed by more than half a dozen manufacturers.
3. VOICE PROCESSING UNIT (APR9600) This block plays very important role in this system. The messages are recorded in the form of human voice by using a microphone. For recording and replaying the messages APR9600 IC is used. APR9600 is a low-cost high performance sound record/replay IC incorporating flash analogue storage technique. Recorded sound is retained even after power supply is removed from the module. The APR9600 has a 28 pin DIP package as shown above. Supply voltage is between 4.5V to 6.5V. During recording and replaying, current consumption is 25 mA. In idle mode, the current drops to 1 mA. Total sound recording time can be varied from 32 seconds to 60 seconds by changing the value of a oscillation resistor. The IC can be controlled simply using push button keys. It is also possible to control the IC using external digital circuitry such as micro-controllers and computers.
HOW APR9600 WORKS? APR9600 works into two modes. 1. Serial mode 2. Parallel mode In serial access mode, sound can be recorded in 256 sections. In parallel access mode, sound can be recorded in 2, 4 or 8 sections. These modes are selected using MSEL1 (Pin24), MSEL2 (Pin 25) and M8 (Pin 9).
Record sound tracks Circuit MSEL1=1 MSEL2=1 –M8=1 RE=0. The maximum length of the 8 tracks is 7.5 seconds. Press M1 continuously and you will see BUSY LED illuminates. You can now speak to the microphone. Recording will terminate if –M1 is released or if the recording time exceeds 7.5 seconds. Similarly, press – M2 to -M8 to record other sound tracks.
DisplayLiquid CrystalDisplay(LCD) The display used is 16*2 alphanumeric LCD1 display. LM016L VDD VSS VEE RW RS D0 D1 D2 D3 D4 D5 D6 D7 E 1 2 3 4 5 6 7 8 9 10 11 12 13 14
LIQUID CRYSTALS A liquid crystal has properties between a solid and a liquid. It has properties more of a liquid. It is more easily affected by temperature.
Construction of LCD A reflective mirror is setup at the bottom. Above it a glass filter with a polarizing film on one side and an electrode on the other is kept. The liquid crystal substance comes next followed by another piece of glass with an electrode towards the LC substance and a polarizing film on the other. There is a cover glass which keeps the inside of the LCD intact.
Basic OperationWhen NO CURRENT: Light is passed through front of LCD It is reflected by the mirror and it bounces back.When there is CURRENT: LC molecules „untwist‟ Light is blocked from passing through. Area becomes darker as compared to others n a character is displayed on LCD.
Speaker The speaker is used to announce or play the recorded message which is already stored in the APR9600 recording IC and which is displayed on the LCD. The speaker is playing most important role in this project. Speaker used is 8 ohm 1 watt speaker.
WORKING OF CIRCUIT The data pins of LCD are connected to the Port0 of the microcontroller. RS= P2.5 RW=P2.6 and EN= P2.7 Port1 is assigned for the message pins of APR9600. The APR9600 is used in random access mode(8 messages). The voice is recorded by using electrets microphone, while recording the voice MSEL1=1, MSEL2=1, M8=1, RE=0. Press M1 continuously and you will see BUSY LED illuminates. Now speak to the microphone. Recording is started, recording will terminate if M1 is released or if the recording time exceeds 7.5 seconds. press M2 to M8 to record other sound tracks.
Playing the stored messages CE=0 to enable device & RE=1 to disable recording & enable playback. By applying low to high signal to APR9600 message pins from microcontroller to play the desired message.
Algorithm Step1: Initialization of LCD. Step2: Wait for some time. Step3: Display welcome message. Step4: Initialization of LCD. Step5: Display “Next stop is:” Step6: Wait for some time. Step7: Display the Stop name. Step8: Give low to high pulse to APR9600 to play the particular message which is displayed on LCD. Step9: Display the next stop name. Step10: Go to step8 to repeat the process 7 times again. Step 11: End
StartFlowchart Define Port 0 as data lines of LCD Define EN=P2.7 RW=P2.6 EN=P2.5 Initialize the LCD Wait for some time Display Welcome message Wait for some time A
A Display message “NEXT STOP IS” Wait for some time Send low to high pulse to apr9600 message pin with some delay in between to play the particular messageDisplay the desired stop name on LCD in accordance with the announcement Wait for some timeRepeat each announcement and rolling message 2 times B
BWait for some time Display message“NEXT STOP IS” 8 messages is finished???? Stop
Hardware PC Target Board of microcontroller Power Supply PCB layout
Advantages The system is easy to build and design. It requires less hardware. The code for rolling the message is easily developed by using Assembly language. The system is not costly. It requires less power to operate. In case of power failure, it can be operated on the battery supply.
Disadvantages The main disadvantage of the system is the APR9600 is having time duration of 60 seconds only. The sound quality is not good enough. If any of the message pin is pressed manually in between the running system the particular message will be played.
APPLICATION In Railway platforms for announcement and displaying the trains schedule. In train buggies for displaying the station names. In Bus stops for announcement and displaying the buses schedule. In Buses for displaying the stop names. In School for any type of notice and lecture time. In Colleges for any type of notice and lecture time Hospitals Roads Shops And many more applications are there.
Future Scope We can introduce the RF module in the system. It can be accessed using GSM modules at any place at any time. By adding GPS we can track our system. By using other type of voice recording IC having duration of time large. We can use graphical LCD instead of numerical LCD. We introduce the RTC for time management.
Conclusion The “Rolling Display with Announcement System” is successfully designed, build and tested.
References Introduction to Embedded System By Mohammed Ali Mazidi Embedded System by Raj Kamal Electronic For You (Magazine) Chip Digit (Magazine) www.embeddedgarage.com www.efy.co.in