Thanks :This project was designed by one of our readers " Mr. Sreenath C J".......
INTRODUCTION
This is a USB Power jukebox system without
microcontroller.
In this project a USB player has been
attached for music enhancement from pen drives/memory cards. It gives lot of
comfort to the user since we can operate it at the time of power failure. We
can also charge USB power devices/Phones and provides output DC voltages.
In this project consist of 3 sections,
Mini ups system, USB power socket and USB audio player and USB power jukebox is
a portable system.
BLOCK DIAGRAM
BLOCK DIAGRAM DESCRIPTION
Standard step down transformer
provides 12V of AC used in this circuit. AC output of transformer connected to
mini ups circuit. The mini ups circuit provides an uninterrupted power supply
to operate 12V, 9V, and 5V DC-powered instruments at up to 1A current. This
circuit consists of LED’s, diodes,
zener diodes, battery, resistors & capacitors. The circuit immediately
disconnects the load when the battery voltage reduces to 10.5V to prevent deep
discharge of the battery. The capacitor C1 provides ripple-free DC to charge
the battery.
The output of mini ups system
connected to USB power socket & USB player. Nowadays, many handheld devices
utilizes this facility of USB port recharge their built-in battery pack with
the help of an internal circuitry. Usually 5V DC, 100mA current is required to
satisfy the input power demand.
USB AUDIO PLAYER MODULE
USB
Player module consists of USB/Memory card slot and music modes or functions can
be operated by a remote. It operates
on 5V,250ma DC supply.
CIRCUIT DIAGRAM
MINI UPS SYSTEM
Fig-1
USB POWER SOCKET
Fig-2
CIRCUIT DIAGRAM DISCRIPTION
MINI UPS SYSTEM
This circuit provides an uninterrupted
power supply (UPS) to operate 12V, 9V and 5V DC- powered instruments at up to
1A current. The backup battery takes up the load without spikes or delay when
the mains power gets interrupted. It can also be used as a workbench power
supply that provides 12V, 9V and 5V operating voltages. The circuit immediately
disconnects the load when the battery voltage reduces to10.5V to prevent deep
discharge of the battery. LED1 indication is provided to show the full charge
voltage level of the battery. Miniature white LEDs (LED2 and LED3) are used as
emergency lamps during power failure at night.
A standard step-down transformer
provides 12V of AC, which is rectified by diodes D1 and D2. Capacitor C1 provides
ripple –free DC to charge the battery and to the remaining circuit. When the
main power is on, diode D3 gets forward biased to charge the battery. Resistor
R1 limits the charging current. Potentiometer VR1 (10K) with transistor T1 acts
as the voltage comparator to indicate voltage level. VR1 is so adjusted that
LED1 is in the ‘off’ mode. When the battery is fully charged, LED1 glows
indicating a full voltage level of 12V.
When the mains power fails, diode D3
gets reverse biased and D4 gets forward biased so that the battery can
automatically take up the load without any delay. When the battery voltage or
input voltage falls below 10.5V, cut-off circuit is used to prevent deep
discharging of the battery. Resistor R3, zener diode ZD1 (10.5V) and transistor
T2 from the cut-off circuit. When the voltage level is above 10.5V transistor
T2 conducts and its base becomes negative (as set by R3, VR2 and ZD1). But when
the voltage reduce 10.5V, the zener diode stops conduction and the base voltage
of transistor T2 becomes positive. It goes into the ‘cut-off’ mode and prevents
the current in the output stage. Preset VR2 (22k) adjust the voltage 0.6V to
make T2 work if the voltage is above 10.5V.
When power from the mains is available,
all output voltages-12V, 9V and 5V-are ready to run the load. On the other
hand, when the mains power is down, output voltages can run the load only when
the battery is fully charged (indicated by LED1). For the partially charged
battery, only 9V and 5V are available. Also, no output is available when the
voltage goes below 10.5V. if battery voltage varies between 10.5V and 13V,
output at terminal A may also vary between 10.5V and 12V, when the ups system
is in battery mode.
Outputs at points B and C provides 9V and
5V, respectively, through regulator ICs (IC1 and IC2) while output A provides
12V through the zener diode. The emergency lamp uses two ultra-bright white
LEDs (LED2 and LED3) with current limiting resistors R5 and R6. the lamp can be
manually switched ‘on’ and ‘off’ by S1.
The circuit is assembled on a
general-purpose PCB. There is adequate space between the components to avoid
overlapping. Heat sinks for transistor T2 and regulator ICs (7809 and 7805) to
dissipate heat are used.
The positive and negative rails
should be strong enough to handle high current. Before connecting the circuit
to the battery and transformer, connect to a variable power supply. Provide 12V
DC and adjust VR1 till LED1 glows. After setting the high voltage level, reduce
the voltage to 10.5V and adjust VR2 till the output trips off. After the
settings are complete, remove the variable power supply and connect a
fully-charged battery to the terminals and see that LED1 is on. After making
all the adjustments connect the circuit to the battery and transformer. The
battery used in the circuit is a 12V, 4.5Ah UPS battery.
USB POWER SOCKET
A USB port, in practice is a capable of
delivering more than 100mA of continuous current at 5V to the peripherals that
are connected to the bus. So a USB port can be used, without any trouble, for
powering 5V DC operated tiny electronic gadgets.
Nowadays, many handheld devices (for
instance, portable reading lamps) utilize this facility of the USB port to
recharge their built-in battery pack with the help of an internal circuitry.
Usually 5V DC, 100mA current is required to satisfy the input power demand.
Fig. shows the circuit of a
versatile USB power socket that safely converts the 12V battery voltage into
stable5V.This circuit makes it possible to power/recharge any USB
power-operated device, using in-dash board cigar lighter socket of your car.
The DC supply available from the cigar
lighter socket is fed to an adjustable, three-pin regulator LM317L
(IC1).capacitor C1 buffers any disorder in the input supply. Resistors R1 and
regulate the output of IC1 to steady 5V,
Which is available at the ‘A type
female USB socket. Red LED1 indicates the output and zener diode ZD1acts as a
protector against high voltage.
PCB LAYOUT
MINI UPS SECTION
FIG-1
USB POWER SECTION
FIG-2
POWER SUPPLY UNIT
All electronics words only
with low DC voltage. We need a power supply unit to provide the appropriate
voltage supply. In this project a Dc voltage source of 12V is used to run and
charge the circuit and regulator IC (7405, 7409) is used provide regulated 5V
and 9V supply.
PCB FABRICATION
The PCB fabrication involves the following steps
1. PREPARATION OF THE LAYOUT
First the circuit is drawn in orcad capture and the layout is prepared
by the orcad layout plus as explained in the layout making procedure. From the
layout plus the mirrored image of the top layer is printed on the butter paper.
Using this, the film can be made and is exposed to the UV.
2. FILM PREPARATION
In this process, the negative of the film is made on photogenic film.
For this, the printed image of the layout in butter paper is placed over the
film and it is exposed to the UV rays from the top so that the film will be
exposed to the UV rays in the regions other than the layout. Then the developer
solution is made and the film is taken out of the exposure unit and is put in
the developer solutions, then the reaction will take place, then the regions
not exposed by UV rays will become transparent and the other regions are dark
in color. Thus the negative is produced. Then the film is washed in fixing
solutions. After that the film is kept for drying.
3. TRANSFERRING OF THE LAYOUT TO
COPPER CLAD
First the copper clad sheet of
required size is cut by using cutting machine. Then the sheet is cleaned by
using steel scrubber. After perfect cleaning of the board, it is dipped in the
photo resist solution so that film of the photo resist is formed on the board.
Then the copper clad sheets placed in an oven for sometime, so that the photo
resist will fixed to the surface of the board.
The next step is to form an image of
the layout on the copper clad sheet. For that, the negative of the layout is
placed over the sheet. Then it is placed on the UV exposure unit so that the UV
rays will fall on the photo resist over the board in the regions of the layout
where the negative is transparent. Then the board is taken out and put in a
developer solution for about 1.15 minutes. After that, the board is washed
gently in water for about one minutes so that the chemical reaction take place
in the regions exposed by the UV rays. Then the board is washed in a dye so
that the dye will be fixed to the layout regions. Thus we get the visible image
of the layout on the board. Then check the layout on the board with the actual
circuit. If any mistakes, the above processes are repeated. If layout is
correct, the board now ready for etching.
4. ETCHING OF THE LAYOUT
When the board is ready for etching it
is placed in the ferric chloride solution. It is checked in regular intervals
to prevent over etching and successive damage to the port. After the etching is
complete, the board is taken out of the etch and washed in water to remove the
excess ferric chloride. Now the copper lines are exposed and hence the body is
checked with the magnifying glass to see whether all the lines in the layout
are clearly formed now the board is ready for tinning.
5. TINNING
For tinning, the PCB is cleaned well
and the flux is supplied to the surface then it is passed through the tinning
machine. In tinning the copper lines are platted with an alloy of TIN &
LEAD.
6. DRILLING
After tinning, the next process is
drilling. In this the holes of required sizes are drilled in the PCB wherever
needed, using an electrical drilling machine.
SOLDERING
Soldering is the process of joining
two or more similar or dissimilar metals by melting another metal having low
melting point.
SOLDERING FLUXES
In order to make the surface accept
the solder readily the component terminals should be free from oxides and other
obstructing films. Soldering flux cleans the oxides from the metal. The leads
should be cleaned chemically or by scrapping using a blade or a knife. Small
amount of lead should be coated on the cleaned position of the leads and the
bit of the soldering iron. This process is called TINNING. Zinc chloride,
ammonium chloride and rosin are the most commonly used fixes. These are
available in petroleum jelly as paste flux. The residues which remain after the
soldering may be washed out with more water accompanied by brushing.
SOLDER
Solder is for joining two or more
metals at temperatures below there melting point. The popularly used solders
are the alloys of TIN(60%) and LEAD(40%) that melt at 375 deg Fahrenheit and
solidifies when it cools. Most of the soldering wires are flux cored type. When
such solder wires are used extra soldering flux is not required.
SOLDERING TOOLS
SOLDERING IRON
It is the tool used to melt the
solder and apply at the joints in the circuit. It operates in 230V mains
supply. The normal ratings of the soldering iron are 10W, 25W, 35W, 65W and
125W. the iron bit at the tip of it gets heated up with in a few minutes. 10W
and 25W soldering irons are sufficient for light duty works.
Soldering gun: it is a gun shaped
soldering tools used especially when more heat is required. Its trigger is a
switch which controls the ac power.
Soldering station is an equipment
which provides an iron and a control console that controls the temperature. The
tip temperature is maintained by a feed back control loop.
DESOLDERING
It is the removal or solder from
a previously soldered joint. Desolder pump is a commonly used device for this
purpose. When the solder melts by the action of the soldering iron, a trigger
on the desolder pump should be activated to create a vacuum. This vaccum pulls
the solder into the tube.
COMPONENTS PRICE LIST
COMPONENTS PRICE
BATTERY
450
TRANSFORMER
60
LM317 12
7805
10
USB MODULE
450
TIP127 15
LM3914
55
LOUD SPEAKER
25
VOLTAGE REGULATOR (7805, 7809) 10
APPLICATIONS
- It can be used for charging mobile phones, iPods etc
- Constant DC Outputs for DC powered devices
- Supports SD/MMC/MS cards for music enhancements
ADVANTAGES
ADVANTAGES
- Backup upto 24hours.
- Portable system
LIMITATIONS
- Only certain phone
supports USB charging
FUTURE SCOPE
-
Small scale USB powered electronic devices can be
operated by this system.
-
USB audio player can compatible with other audio
devices ,amplifiers etc
-
Upcoming new i-pods requires USB charging
CONCLUSION
One of the primary
objectives of an engineer is to endeavor to deliver best product or most
efficient service at the lowest cost to the end user. System has been tested
and was found to meet the expected result.
Aim of this project is
to design and construct USB power jukebox device. We have accomplished our aim
and were successful in creating the device.
BIBLOGRAPHY
-
http://www.electronicsforu.com
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