Presentation on theme: "REMOTE CONTROL OF DEVICES USING CELLPHONES Shuhab-u-Tariq (1SI03EC109)"— Presentation transcript:
REMOTE CONTROL OF DEVICES USING CELLPHONES Shuhab-u-Tariq (1SI03EC109)
INTRODUCTION Telephone operated device control circuit which enables switching ON & OFF of appliances through telephone lines. It senses the telephone ring. Automatically switches call to this system, after pre-defined rings. Switches ON/OFF the load depending upon the key pressed by the caller.
BASIC BLOCK DIAGRAM
RING DETECTOR & SCHMITT TRIGGER SECTION
RING COUNTER CUM SWITCHING UNIT This Section counts the number of rings and lifts the cradle automatically after pre-defined number of rings. IC 4017 is used to count the number of rings. The triggering action is carried out by relay driver circuit, which comprises of two Darlington transistors with a relay.
Q1 Q2 Q6 Q3 RESET CLOCK CLOCK ENABLE C OUT Q9 Q4 Q8 Q7 Q4 Q9 C0C0 Q0 Q5 R CK CECE Q8 +Vcc Q5 Q1 Q0 Q2 Q6 Q7 Q3 IC 4017 DECADE COUNTER GND
CIRUIT DIAGRAM OF RING COUNTER CUM SWITCHING & CONTROLLING UNIT 3 Q0 2 Q1 4 Q2 7 Q3 10 Q4 1 Q5 5 Q6 6 Q7 9 Q8 11 Q9 R2 R3 R1 16 IC S1 +5 V CLOCK INPUT from Schmitt Trigger RESET SWITCH D1 8 TR1 R4 TR2 N/O N/C +12V RLC1 R5 D2 LE D To Telephone Line RING COUNTER SECTIONSWITCHING SECTION
DTMF DECODER & BCD TO BINARY CONVERTER MODULE DTMF – Dual Tone Multiple Frequency Resultant signal of two tones at the same time for any key pressed f(t) = Asin(2*П*fa*t) + Bsin(2*П*fb*t)
Pin Diagram of MT8870
Pin Diagram of IC 74154
DTMF to Binary converter
Function Decode Table
LATCH & LOAD DRIVER SECTION This section executes the command send by caller by latching the load to previous state on/off. Terms and components used here: D flip-flop - It is incorporated in IC driver IC- High voltage and high current driver IC is used to drive low impedance relay.
D flip flop an overview D Q CLOCK TRANSIENT DATA SINCE LAST POSITIVE GOING CLOCK DATA HELD IN LATCH STATE OF D INPUT CLOCKED TO Q OUTPUT ON RISING CLOCK EDGE FIG 3
Timing diagram D INPUT CLOCK INPUT Q OUTPUT TIME FIG 4
POWER SUPPLY UNIT 230AC X1X1 C1 D2 1 C2 C3 IC D1 1 9V C4 IC V +5V
CONCLUSION Low power consumption, and compact in size. From any distance appliances can be controlled, overcoming the limited range of infra-red and radio remote control. High reliability, due to the usage of semi conductors.