project describes a technique of adding the remote control feature to an
electrical appliance. The goal is to construct a black box where you can
plug-in your 120V AC appliance (it can be easily modified for 220 V mains
supply too) and control the ON and OFF operations with a TV or DVD remote that
uses modulated infra-red (IR) pulse train of 38 KHz frequency. I did this
project for my wife who studies late at night on her bed and later feels tired
to stand up and turns the light off. Now she does it from bed with the TV
remote. The good thing about this project is that it does not use any
microcontroller and is only based on the CD4017 decade counter IC.
Circuit diagram
The
original circuit diagram for this project was published in the May 2005
issue of theElectronics
For Youmagazine.
The circuit diagram below is mostly the same. It uses a TSOP1738 IR receiver
module at the input side to receive the 38 KHz frequency IR pulses from the
remote control. Under normal condition, the output pin of the IR module is at
logic High, which means the transistor T1 (BC557 PNP) is cut-off and its collector
terminal is at logic Low. The collector of T1 drives the clock line of the
CD4017 decade counter.
Now
lets see what happens when somebody faces a TV or DVD remote towards the
TSOP1738 and presses any key on it. The TSOP 1738 module receives the train of
38 KHz IR pulses from the remote, that makes its output to oscillate too. These
pulses are inverted at the collector of T1, which finally go to the clock input
of the decade counter. The arriving pulses could increment the CD4017 counter
at the same rate (38 KHz), but because of the presence of the RC filter circuit
(R1 = 100K, C1 = 10 uF) between the collector and the ground, the train of
pulses appear as a single pulse to the counter. Thus, on each key pressing, the
CD4017 counter advances only by a single count. When the user releases the key,
the C1 capacitor discharges through the R1 resistor, and the clock line is back
to zero. So every time the user presses and releases a key on the remote, the
CD4017 counter receives a single pulse at its clock input.Initially,
when the circuit is just powered on, the Q0 output of the CD4017 decade counter
goes high. The counter increments for each low-to-high going pulse arriving at
its CLK pin (14). When the first pulse arrives, Q0 goes Low and Q1 is turned
High. This activates the relay and the AC appliance connected to it is turned
on. The status LED connected to Q1 also glows to indicate the appliance is
switched on. When the user presses a key again, the second pulse arriving at
the CLK line increments the counter by 1. This makes Q1 back to Low (which
means the relay is deactivated and the appliance is turned off) and Q2 is
pulled High. Since Q2 is wired to the Reset input, the second key press
actually brings the CD4017 IC back to the power-on-reset conditions with Q0
High. Thus, it basically operates as an ON/OFF toggle switch controlled with
any key of an infrared remote.
The
power supply for the circuit can be derived from the mains AC itself using a
step down transformer and a bridge-rectifier circuit. For +5V power supply, the
LM7805 regulator IC can be used as shown below.
I
have enclosed the circuit board with the power supply inside a wooden box as
shown in the pictures below. The electrical appliance to be controlled can be
powered from the AC outlet at the front side.
This
was a very simple and fun project to do. If you are thinking about making this
device for yourself, be careful with the direct 120 V AC lines used in the
project.
FIG:- Funtional Block diagram EXPLANATION:-
The robot uses IR sensors to sense the line, an array of 8 IR LEDs (Tx) and sensors (Rx), facing
the ground has been used in this setup. The output of the sensors is an analog signal which
depends on the amount of light reflected back, this analog signal is given to the comparator to
produce 0s and 1s which are then fed to the uC.
Left Center Right
Sensor Array
Starting from the center, the sensors on the left are named L1, L2, L3, L4 and those on the right
are named R1, R2, R3, R4.
Let us assume that when a sensor is on the line it reads 0 and when it is off the line it reads 1
The uC decides the next move according to the algorithm given below which tries to position the
robot such that L1 and R1 both read 0 and the rest read 1.
L4 L3 L2 L1 R1 R2 R3 R4
1 1 1 0 0 1 1 1 Desired State L1=R1=0, and Rest=1 Algorithm: 1. L= leftmost sensor which reads 0; R= rightmost sensor which reads 0. If no sensor on Left (or Right) is 0 then L (or R) equals 0; Ex: Left Center Right Here L=3 R=0 Left Center Right Here L=2 R=4 2. If all sensors read 1 go to step 3, else, If L>R Move Left If L<R Move Right If L=R Move Forward Goto step 4 3. Move Clockwise if line was last seen on Right Move Counter Clockwise if line was last seen on Left Repeat step 3 till line is found. 4. Goto step 1. L4 L3 L2 L1 R1 R2 R3 R4 1 0 0 1 1 1 1 1 L4 L3 L2 L1 R1 R2 R3 R4
1 1 0 0 0 0 0 0
will be updated soon...............................................
#include <avr/io.h>
#include <util/delay.h>
#define lcd_port PORTD
#define rs 0
#define rw 1
#define en 2
*********make a HEADER FILE named lcd1 and paste it in util folder of avr
*********LFR WITH LCD CONNECTED ON PORT D*********88
#include <avr/io.h>
#include <util/lcd1.h>
#include <util/delay.h>
Electronics within you!! Note: 1. ALL QUESTIONS ARE
COMPULSARY .
maximum marks:100 2.NO Negative Marking 3.Each Question Carries 2 Marks Name:
rollno:
branch: year:
1. Which is not a "common" value of resistance: a)2k7 b)4k4 c)1m8 d)330R 3. The four symbols are:
7. Identify the correctly connected LED: a)A b)B
c)C d)D 9. The number
0000(ignore carry) would appear just immediately after (a) FFFF
(hex) (b) 1111 (binary) (c) 7777 (octal) (d) All of the above. 11.what is the frequency of a clock waveform
if the period of the wave form is 1.5 us? a) 8khz
b)0.8 khz c) 0.8 mhz
d)8mhz 13.The.................ensures
the only one IC is active at a time to avoid a conflict caused by two IC’s
writing different data to the same bus. a)Control
bus b) control instructions c)Address
decoder d)CPU 15.A basic multiplexer can be
demonstrated through the use of a a)Single
pole relay b) DPDT Switch c)Rotatory
Switch d)Linear stepper
17.It
is required to construct a counter to count upto 100(decimal). The minimum
number of flipflops
required to construct the counteris
(A)
8 (B)
7 (C)
6 (D)
5
18.As a general rule for a stable Flip-Flop triggering,the clock
pulse rise and fall times must be:
a)very long
b)
very short
c)at
a maximum value to enable the input control signals to stabilize.
d)of
no consequence.
19.What type of circuit is used at the interface point of an
output port in the microprocessor?
a)decoder b)latch
c)tri –State Buffer d)none
21.The input/output relationship of the common –collector and
common-base amplifiers is:
a)
270 degree b)180 degree c)90 degree d)0 degree
23.The voltage where current may start to flow in
a reverse-biased pn junction is called the
a) breakdown voltage
b)barrier potential
c)forward voltage
d)biasing voltage
25. 4 resistors in ascending order are:
a)
22R 270k 2k2 1M b)
4k7 10k 47R 330k
c)
3R3 4R7 22R 5k6 d)
100R 10k 1M 3k3
27.The
control terminal (pin5) of 555 timer IC is normally connected to ground
through a capacitor
(~ 0.01μF). This is to
(A)
protect the IC from inadvertent application of high voltage
(B)
prevent false triggering by noise coupled onto the pin
(C)
convert the trigger input to sharp pulse by differentiation
(D)
suppress any negative triggering pulse
32.in 8051 microcontroller The contents
of the accumulator after this operation
MOV A,#0BH
ANL A,#2CH
will be a) 11010111 b) 11011010 c)
00001000 d) 00101000
36. channel current
is reduces on application of a more positive voltage to the GATE of the
depletion mode
n-channel MOSFET (true/false)
37.. Which of the
following effects can be caused by a rise in temperature
a. Increase in MOSFET current
(IDS) b. decrease
and then Increase in BJT current (IC)
c. Decrease in MOSFET current
(IDS) d. increase and
then Decrease in BJT current (IC)
38.
This figure is a schematic representation of a/an:
A.
differential amplifier. B.
inverting amplifier.
C.
noninverting amplifier. D. voltage
follower. 41. A red-red-red-gold resistor in series with
an
orange-orange-orange-gold resistor produces: 5k5 35,200
ohms 55k None
of the above 43. The signal at the collector
will be . . . with the base. Inverted
. . . In-phase
. . . C)no
output d)none of these
44.What does ‘0L’or ‘1’ on a
digital multimeter stands for?? A: A Open Circuit B: A Closed Circuit C:
Inductance D: None of these 45. What value does hFE on
a digital multimeter represent? A:
Voltage GainB: Current GainC: ‘Beta’ value of the transistor D:
‘alpha’ value of the transistor 46. On the transistor chip BC
547,what does B stands for? A:
A silicon made transistor B: A germanium made transistor C:
A High Power Transistor D: A Low frequency Transistor
49. In an intrinsic semiconductor, the Fermi-level is
(A)
closer to the valence band
(B) midway between
conduction and valence band
(C)
closer to the conduction band
(D) within the valence
band
2.The
resistor identified in brown is called the: a)Base bias resistor
b)Load resistor
c)Emmiter feedback resistor
d)Bypass Resistor
4. The purpose of the
capacitor:
a) To pass AC on the input to the base.
b) To allow the
transistor to self-bias c) Block DC from the input line
d) To allow the stage to operate 6. A capacitor and coil in parallel is called:
a)Tuned circuit
b)A Timing circuit
c)A delay circuit
d)A Schmit circuit
8. What is the
octal equivalent of the binary number: 10111101 A: 675
B: 275 C: 572
D: 573
10.The following waveform pattern is for a(n) ________.
a)2 input AND gate
b)2 input OR gate
c)Exclusive-OR gate d)none of these
12.In a
16-bit microprocessor, words are stored in two consecutive memory locations.
The entire word can be read in one operation provided the first
(a) word is even (b)
word is odd
(c) memory location is
odd (d) memory address is even
14.The
technique of assigning a memory address to each I/O device in the computer system is
called:
a) memory mapped I/O b)Ported I/O
c)dedicated I/O d)Wired I/O
16.The
............ is defined as the time the output is active divided by the total
period of the output signal.
a)On time b)Off
time c)Duty cycle d)Active ratio
20.when
transistors are used in digital circuits the usually operate in the:
a)active
region
b)breakdown region
c)saturation and cutoff region
d)Linear region
22.The dc current through each diode in a bridge
rectifier equals:
a)the load current
b)half the dc load current
c)twice the dc load
d)one fourth the dc load
24.. If the voltage on the base of
a transistor increases, does it:
a)Turn On b)Turn Off c)Not enough information
d)Remain the same
26: A resistor and capacitor in series is called
a:
a)Pulse circuit
b)Timing/Delay circuit
c)Oscillator Circuit/Frequency Circuit
d)Schmitt Circuit
28. Technician A says that LED-1 will be ON and
LED-2 will be OFF when the circuit is connected as shown below. Technician B
says that both LED-1 and LED-2 will be ON when the circuit is connected as
shown below. Who is correct? :
a)technician A only. b)technician B only
.
c)neither Tech A nor Tech B. d) Technician A nor Technician B
29.
In an
intrinsic semiconductor, the Fermi-level is
(A)
closer to the valence band (B) midway
between conduction and valence band
(C)
closer to the conduction band
(D) within the valence
band
30. The dual of the Boolean expression: x + y + z is
(A)
x .y + z (B) x
+ yz
(C) x . y . z (D) x.y.z
31.
The type of
power amplifier which exhibits crossover distortion in its output is
(A)
Class A (B)
Class B (C)
Class AB (D)
Class C
33.Zener diodes are most
commonly used in:
A.
voltage amplifier circuits.
B. oscillator circuits.
C. power supply circuits. D. current limiting circuits
34.A resistor with colour bands Red, Violet, Green and Black will have a
value
(A)27 K±10%K (B)2.7 M±20% K (C)270 K±5% K (D)2.7 K±2%K
35.Thefollowing data refers to an experiment
carried out on a Zener diode:
Reverse voltage
Reverse current
1 V
1 µA
2 V
2 µA
3 V
10 µA
4 V
20 µA
The Zener voltage
will be between:
(a)1 V and 2 V
(b) 2 V and 3 V (c) 3 V and 4 V
(d)none of these
39. What
is the approximate characteristic voltage that develops across a red LED? a)1.7 V b)3.4V c)0.6V d)5V
40. The resistor marked is:
Base
Bias Resistor
Load Resistor
Emitter Feedback Resistor
Bypass Resistor 42. Name the 4 components:
This
mini inverter circuit can be completed through the following simple steps:
Cut two sheets of aluminum of 6/4 inches each.
Bend one end of the sheet as shown in the diagram. Drill appropriate sized
holes on to the bends so that it can be clamped firmly to the metal cabinet.
Also drill holes for fitting of the power transistors. The holes are 3mm in
diameter, TO-3 type of package size.
Fix the transistors tightly on to the heatsinks with the help of nuts and
bolts.
Connect the resistors in a cross-coupled manner directly to the leads of the
transistors as per the circuit diagram.
Now join the heatsink, transistor, resistor assembly to the secondary winding
of the transformer.
Fix the whole circuit assembly along with the transformer inside a sturdy, well
ventilated metal enclosure.
Fit the output and input sockets, fuse holder etc. externally to the cabinet
and connect them appropriately to the circuit assembly.
Parts Required for the circuit diagram
You will require just the following few components for the construction:
R1, R2= 100 OHMS./ 10 WATTS WIRE WOUND
R3, R4= 15 OHMS/ 10 WATTS WIRE WOUND
T1, T2 = 2N3055 POWER TRANSISTORS (MOTOROLA).
TRANSFORMER= 12- 0- 12 VOLTS / 5 AMPS.
AUTOMOBILE BATTERY= 12 VOLTS/ 32AH
ALUMINUM HEATSINK= CUT AS PER THE REQUIRED SIZE.
VENTILATED METAL CABINET= AS PER THE SIZE OF THE WHOLE ASSEMBLY
a)Pulse circuit
.jpg)
