Important Android Codes:-

Important Android Codes:-

Low-Range AM Radio Transmitter:-

Low-Range AM Radio Transmitter:-

MONO BOX:-

BY USING THE BELOW VIDEO U CAN PREPARE UR MONO BOX TO LISTEN MUSIC BY CONNECTING TO YOUR MOBILE PHONES OR ANY DEVICES

ALL THE BEST................../////////////////////////////////

Temperature control:-

Here is the circuit of a simple and inexpensive temperature controller which can control temperature  from about 20°C to 200°C with an accuracy of 0.5°C

PARTS LIST

RESISTORS

R1 , R2 ,	8.2 K
R4	1K THERMISTOR
R5	470 Ohm
R6	22 K
R7	820 Ohm
R3	All 100 Ohm

DIODES

D1	Zener diode 5.1V 400mW
D2 , D5 , D6	1N4001
D3 , D4	15V 1W

OTHERS PARTS

IC1	op-amp 741
T1	BC147
X1	18V
C1 , C2	Capacitor 470μ 50 V
R1	RELAY 12V 250Ω
S1	1-POLE, 10 way switch

 

 

CIRCUIT DIAGRAM

CIRCUIT DESCRIPTION:-

The controller has been designed and fabricated using the  op-amp IC 741 and a 1k thermistor as the temperature sensor. It is based on the principle of Wheatstone bridge. The ratio arms R1 and R2 of the bridge are kept fixed (say unity). The voltage across the thermistor, i.e. across the arm R4, is compared with the voltage across the variable arm R3 which is kept fixed for a particular temperature (using the op-amp).

When the bridge is not balanced the output of 741 drives transistor BC147 to conducting state. Thus, the relay is energised and switches the heater on. As the temperature increases, the voltage across the thermistor decreases and when this voltage is equal to the voltage across R3 (i.e. the preset value) the output of 741 becomes zero. The transistor then stops conducting, the relay is de-energised, and the heater is switched off. Band switch S1 gives the different ranges of temperature  and potentiometer VR1 is used for fine adjustments.

Electronics Thermometer:-

Clinical thermometer is only used by doctor because it is difficult to read. Here is a circuit of electronics thermometer used to measure vast range of temperature from -20⁰C to 125⁰C. This single circuit electronics thermometer can be used to measure different temperature. The wide range of temperature measurement made this circuit versatile.

Circuit Description of electronics thermometer

This entire circuit “Electronics thermometer” is built and fabricated around silicon diode D₁ (1N4148) and Operational amplifier IC. Diode D₁ is used as temperature sensor, temperature determined the value of voltmeter drop across diode i.e. at room temperature voltage drop is 0.7V and is reduce by about 2mV/⁰C.

For temperature-to-voltage conversion in electronics thermometer an operational amplifier is used. The input voltage at non-inverting pin 3 of IC₁ is fixed by VR₁, R₁, & R₂ where sensor diode D₁ forms a feedback path. The output of IC₁ is directly depends on the voltage across the diode.

Operational amplifier IC₁ is used as voltage amplifier which amplifier the output from IC₁. Finally, ammeter is used to indicate the temperature.

PARTS LIST

Resistors (all ¼-watt, ± 5% Carbon)

R₁ = 680 Ω

R₂ = 1 KΩ

R_3, R₄, R₅ = 1 KΩ

R₆ = 6.8 KΩ

R₇ = 10 KΩ

VR₁ = 2.2 KΩ

VR₂, VR_3, VR₅ = 10 KΩ

Capacitors

C₁, C₃ = 0.1 µF

C₂ = 10 µF/16V

C₄ = 10 µF/16V

Semiconductors

IC₁, IC₂ = µA741

D₁ = 1N4148 (Sensor)

Miscellaneous

                                                           M₁ = 1mA-0-1mA or 0-1mA Ammeter

Microprocessor based home security system:-

In this advance world security system is in high end so the security breakers are. Now it’s time to live free, live secure. By keeping these all thing in mind (problem from burglary) the innovative group dreamlover technology designed a microprocessor based project “Microprocessor-Based Home Security System”. This advance security system not only let you know but also alert police immediately. In the project 8085 microprocessor based home security system we can control siren, telephone (via cradle and redial switches) and cassette player (alert message is recorded already)

Working of the system

The whole circuit of 8085 based home security system consist transmitter, receiver, Phase-Locked-loop and processing section as shown in Block diagram.

 

The mechanism of the project “Microprocessor Based-Home Security System” is very simple. As this project is IR based, the IR ray from transmitter is focused in the base of phototransistor of receiver fitted in opposite to each other. The property of phototransistor is that whenever the IR ray focused on its base is obstructed, the microprocessor as per program burnt in EPROM which further control siren, telephone and cassette player.

Circuit Description

The whole Project “8085-Microprocessor based security system” is divided into two main sections i.e. Hardware and Software.

 

Hardware: The complete circuit-Diagram of “Microprocessor Based Home Security System” is shown in figure 1. The transmitter section is designed and fabricate around timer IC NE555 wired as astable multivibrator followed by transistor T₁ and IR LED. The oscillated frequency of transmitter section is decided by resistor R₁and R₂, preset VR₁ with capacitor C₁. The output from pin 3 of IC₁ is given to base of transistor T₁ through resistor R₃ for amplification as per required and given to IR LED. The modulated IR signal is transmitted by IR LED₁.

The IR transmitted signal is focused on the base of photo transistor. The output from photo transistor is given to transistor T₃ followed by op-amp (IC₂) for amplification. The amplified signal from IC₃ is given to input pin 3 of Phase-Locked-Loop (PLL) IC LM567 (IC₃) through capacitor C₄. The normal use of PLL IC (IC₃) is frequency decoder so is here in order to drive the load. The tuning frequency is determined by variable resistor VR₂ and current controlled oscillator by resistor R₁₂. The tuning frequency (6-10 KHz) should match with modulating frequency transmitted by transmitter. Pin 8 of IC₃ is connected to base of transistor T₄ through resistor R₁₃. Glowing LED₁ indicate receiving signal is locked to transmitting signal. Transistor T₅ is used as relay driver in order to energize the relay RL₅. Relay RL₁ energized normally when transmitted IR signal falls on phototransistor T_2, at this time microprocessor does not get any input. But when IR signal is interrupted microprocessor get high (TTL-level) signal through port A of Programmable Peripheral Interface (PPI).

The microprocessor start working as per command loaded in the EPROM (IC₅) when high input is given from PLL. Octal latch (IC₆) is used for interface between low-order multiplexed address and latch lines AD₀ through AD₇ of microprocessor (IC₄) and EPROM in order to separate Address line A₀ through A₇ from data line D₀ to D₇ by latch-enable signal (ALE), while high-order address lines A₈ through A₁₀ is directly connected to EPROM.

ALE pin (30) of microprocessor is connected to pin 11 of IC₆. The output changed according to input data when ALE is high, if ALE goes low the lower-order address is latch at the output of IC₆.

RD and IO/M pin (32 and 34 respectively) of microprocessor (IC₄) is used to generate Chip-Select signal (CS) with the help of NAND gates.

Pin 18, 19, 20 and 25 of IC₇ are connected to base of relay driver transistor T₆ to T₉ through resistor R₁₉ to R₂₂ respectively. The high signal (interrupt of IR signal on the base of phototransistor) on these pin energizes the relay RL₁ to RL₄. For reset switch SW₁ is used.

Polarity reversed in the telephone line is build around optocoupler ICs (IC₈ and IC₉). As we all know that normal TIP of telephone set is positive in compare to Ring LED of telephone line. When the handset is in OFF-HOOK position, a loop current of 10mA is assumed for flowing in telephone line.

When the polarity reversed occurs from DC line the internal LED of IC₈ conduct which further glow LED₃ for indicating polarity reversed. Internal LED of IC₉ goes off and its pin 5 goes high in order to provide line reversed sense signal to microprocessor using pin 14 of programmable peripherals interface (PPI) IC (IC₇).

Relay connection

The cradle switch of telephone set is replaced by DPDT relay (RL₃). The four pads connection of PCB with cradle switch is now connected with relay. The two shorter distance pad when handset is placed in the cradle is connected to N/C contract of relay RL₃ where other two pad which is shorter distance when handset is off-hook are connected to N/O contract of same relay. Relay RL₂ is connected to redial bottom of telephone set parallel. When relay RL₃ is energized relay RL₂ is also energized to switch on the redial bottom which automatically dialed already loaded number (i.e. police or any help line). Relay RL₄ activate siren when ever receiving IR signal is interrupted until the reset bottom is pressed. Lastly relay RL₁ switched the audio cassette player in which victim detail is already recorded. The speaker connection of audio cassette player is connected to microphone of telephone to convey the alert message.

Software: The flowchart showed in figure: 6 shows the assembly language program. 99H word is used here to control device interface IC (IC₇) where port A and C as input port and B as output. At first microprocessor read the status of port A, when port A is high siren is activated, redial switch is activated and emergency number is dialed. After dialing number redial bottom gets switch off. Now microprocessor read the status of port C which further checks the polarity reversal of telephone line.  After detection of polarity reversal, the audio player is activated. When the message is finished the player automatic gets turned off.

 

Click to download program code for microprocessor-based home security system

PCB DESIGN: The actual size of PCB board must be 17.5cm×9.7cm

 

Click to download PCB Design in high resolution

PARTS LIST

Resistors (all ¼-watt, ± 5% Carbon)

R1, R2 = 5.6 KΩ R3, R16, R18 – R22, R25 = 4.7 KΩ R4 = 100 Ω R5 = 3.9 KΩ R6, R8, R12, R15, R17 = 1 KΩ R7, R10, R11, R13, R14 = 10 KΩ R9 = 100 KΩ R23 = 120 Ω R24 = 470 Ω VR1 = 47 KΩ VR2 = 10 KΩ

Capacitors

C1 = 3.3 nF ceramic disc C2, C6, C13, C14 = 0.1 µF ceramic disc C3, C8 = 0.01 µF ceramic disc C4 = 1 nF ceramic disc C5 = 10 µF, 25V electrolyte C7 = 2.2 µF, 25V electrolyte C9 = 10 µF, 10V electrolyte C10, C11 = 10 pF ceramic disc C12 = 1000 µF, 50V electrolyte

Semiconductors

IC1 = NE555 (timer IC) IC2 = µA741 (operational amplifier) IC3 = LM567 (Phase-Locked-loop) IC4 = 8085 (Microprocessor) IC5 = 2732A (EPROM 4k) IC6 = 64LS373 (Octal Transparent Latch) IC7 = 8255 (programmable peripheral interface) IC8, IC9 = MCT2E optocoupler IC10 = 74LS00 (NAND gate) IC11 = 7809 (9V regulator) IC12 = 7812 (12V regulator) T1, T3 – T9 = BC548 (NPN transistor) T2 = L14G1 (Phototransistor) D1 = 1N4148 (Switching diode) D2 – D10 = 1N4007 (rectifier diode) LED1 – LED3 = Red LED IR LED1 = Infrared Led

Miscellaneous

X1 = 230V/50 Hz or 110V/60 Hz AC primary to 12V-0-12V, 300 mA secondary transformer XTAL = 3.5 MHz crystal SW1 = Push-to-on switch SW2 = On Off switch RL1, RL2, RL4, RL5 = 12V, 200 Ω, 1C/O relay RL3 = 12V, 200 Ω, 2C/O relay

Temperature Indicator Using AT89C52:-

                                              Different temperature indicator project with discrete component is already published. Now, here is a microcontroller based temperature indicator with LCD for better and precise reading. A temperature sensor DS1621 is used here for better result. As we know that programming language “C” is less complicated with well-defined syntax in compare to Assembly language so we write program for microcontroller in “C”.

Circuit description:-

The circuit of temperature indicator is designed around microcontroller AT89C52 where DS1621 is used as temperature sensor. The block diagram of temperature indicator using AT89C52 is shown in figure 1.

The temperature sensor IC₃ is used to sense temperature and read as 9-bit value. The pin 1 and 2 of sensor (IC₃) is connected to pin 11 and 10 respectively of microcontroller (IC₂) as shown in circuit diagram. The sensor (IC₃) activates its thermal alarm output in exceeding of user-defined high temperature until temperature drop below user-defined low temperature. Non-volatile memory is used to store user-defined temperature.

A crystal oscillator X_TAL1 is connected to X_TAL pin of microcontroller (i.e. pin 18 and 19) for operating of microcontroller. A high pulse on RST pin (pin 9) through capacitor C₅ is given while the oscillator is running for reset the microcontroller. Pin 31 is also connected to +Ve supply for execution of internal program. During flash programming at 12V programming is selected pin 31 is also used to receive 12V programming enable voltage.

The 16*1 LCD is used as display where VR₁ is used to control the intensity of display. The connection of LCD is given in table 2 where pin 15 and 16 is not used.

Software:- A cross-complier C51 version 7.10 from keil software is used here for compiling the program code written in C.

Click Here To Download Program Code

TABLE 1
DS1621 Command Set
Instruction	Description	Protocol
Read Temperature	Reads last converted temperature value from temperature register.	Aah
Read Counter	Reads value of count remaining from counter.	A8h
Read Slope	Reads value of slope accumulator.	A9h
Start Convert T	Indicates temperature conversion.	EEh
Stop Convert T	Halts temperature conversion.	22h
Access TH	Reads or writes low temperature limit value into TH register.	A1h
Access TL	Reads or writes low temperature limit value into TL register.	A2h
Access Configuration	Reads or writes configuration data to configuration register.	Ach

TABLE 2
Pin Connection of the LCD
Pin No.	Functions
Pin 1	Ground (Gnd)
Pin 2	+Vcc
Pin 3	V0 (display intensity control)
Pin 4	RS (connected to pin P3.2 of AT89C52)
Pin 5	R/W (connected to pin P3.3 of AT89C52)
Pin 6	EN (connected to pin P3.4 of AT89C52)
Pin 7	D0 (connected to pin P1.0 of AT89C52)
Pin 8	D1 (connected to pin P1.1 of AT89C52)
Pin 9	D2 (connected to pin P1.1 of AT89C52)
Pin 10	D3 (connected to pin P1.3 of AT89C52)
Pin 11	D4 (connected to pin P1.4 of AT89C52)
Pin 12	D5 (connected to pin P1.5 of AT89C52)
Pin 13	D6 (connected to pin P1.6 of AT89C52)
Pin 14	D7 (connected to pin P31.7 of AT89C52)
Pin 15	Backlight +Vcc (not used)
Pin 16	Backlight Gnd (not used)

PARTS LIST

Resistors (all ¼-watt, ± 5% Carbon)

R1 = 1 KΩ R2 = 47 KΩ R3 = 10 KΩ R4, R5 = 4.7 KΩ VR1 = 1 KΩ (Preset)

Capacitors

C1 = 470 µF/25V (Electrolytic) C2 – C4 = 0.1 µF (Ceramic) C5 = 10 µF/16V (Electrolytic) C6, C7 = 33 pF (Ceramic)

Semiconductors

IC1 = LM7805 (Voltage Regulator) IC2 = AT89C52 (Microcontroller) IC3 = DS1621 (Temperature Sensor) D1 – D4 = 1N4007 (Rectifier Diode) LED1 = RED