Main features of the project are it, not only display the called number but also speaks out the number. In case of any security threat to the cashier, a panic foot switch can be connected on a suitable place or many such switches can be installed , press the switch to dial the nearest police station number to inform about the emergency situation in the bank.
This project has been designed on the intel’s most powerful microcontroller 8051.
Circuit explanation : Port 3 has been connected to 4×3 matrix key pad.to be used to display token number. Three nos seven segments are used to display the numbers. Data lins of the seven segment are connected to port 0. ,digit control lines are connected to port 1 p1.0,p1.1 and p1.2 lines. Q1,Q2 &Q3 are digit driver transistors. R18,19,20 are current limiting resistors.
Ic4 74ls245 is used as a buffer to drive the common cathod seven segments.
R3 to r9 are current limiting resistors. Port0 is a open source port so we have to connect a pullup resistor in order to make this port a normal digital i/o port. 4.7k sil array resistance is connected to port 0 as external pull up resistors.
Ic5 is one time recordable speech ic where all our messages are stored .This ic is addrasable so the address are generated by P 2.4, P2.5, P2.6 & P2.7 PINS to trigger the required message. Resistor r18,r19,r20 and r21 are current limiting resistors.
This speech ic5 is high logic active so initially we have to make all these pins to low logic through our programs. And whenever we have to trigger any speech we output logic high on those pins.Binary address is generated on those pins by our program. Upto 12 messages can be stored in this ic. And the total duration of these messages should not be more than 42 seconds at 6k sampling rate. If you increase the sampling rate, the quality of sound will improve but storage duration will reduce. 6k smpling rate is quite enough to speak numbers and emergency message. This is is driven by 3.3vdc at pin 9 and 12 through r14 resistor.
D5 Is 3.3v zener diode connected for the protection circuit.c9 is filter capacitor. Capacitor c10 isconnected for internal clock geneation. Vr1 along with r15 are sampling rate adjust resistors .voice is out from pin 7 and is coupled to pin 3 of ic6 through c12 and vr2 volume control. Capacitor c11 and r16 are for noise reduction purpose.
Ic6 ,Lm 386 is audio amplifire ic driven by 12v dc.capacitor c13 and c17 are filters. Amplified audio is out from pin 5 and drives the speaker through acoupling capacitor c16.
Resistor r17 and capacitor c14 are tone correctors.
Ic3 is an opto coupler whenever a foot switch is pressed , led inside will glow and photo transister will conduct making it’s collector to a low logic which is connected to p1.3 pin 4of the microcontroller when ever foot switch is pressed ,this pin will become low and microcontroller will output the address of siren and an emergency siren will be heard.
Circuit is driven by 5v dc power supply current drawn is not more than 500ma,
A bridge rectifier circuit d1 to d4 capacitors c1 to c4 are filter capacitors. 9v 1 ampere transformer is connected at pcon1. ic 1 is 5v regulator 7805. Ld1 is power indication led. R1 is current limiting resistor.
PORT0 has open source internally so we have connected 4.7kX8 SIL,pullup resister to make them digital i/0 pins .This port is used as input port all the sensors are connected to this port.
PGM SW is connected to p1.4 pin(5) of port1 is input pin this switch is used to store the telephone number. Sw1 is alarm stop switch connected to pin6(p1.6)of the microcontroller,used as input pin. Port2,pin number ,25,26,27 and 27 are used as output pins
All the input PORT pin logic state is normally high and they are active low.
All the output PORT pin logic state is normally low and thay are active high pin.
Port1 pins are normally high and they are active low;.
Operation : connect the transformer out put to pcon1 power indication led LD1 will come on enter some number from the matrix keyboard, you will find characters displayed on the seven segment. When number entry is finished ,press ‘#’ and you will hear the number entered two times. If you want to repeate this operation just press * and it will again speak out the previous displayed number. Pressing the # again will clear display and you can enter new number.
Circuit is driven by 9v 1 ampere transformer connected to PCON1
Press the PGM SW and store the emergency telephone number you wants,the device should call you in case of an emergency. Every time when you press a key you will see number displayed on the display. Suppose you want to store telephone number 23887151 so press these keys one by one at the end press’#’ key. ‘#’ is like end of telephone number key. So you will have to press 23887151#, ‘A’ displayed indicates that the telephone number has been stored. Now release the PGM SW,