Introduction: POCKET SIZED BLUETOOTH AMPLIFIER CUM POWER BANK
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Hi guys, so this is an instructable for people who love carrying around their music with them as well as hates carrying around their phone charger searching for a power outlet ;-) .
This is simple cheap and easy to make portable bluetooth speaker cum power bank just the size of a normal 5 inch smart phone which can easily fit inside any pocket.
This decive has a 5000 mah battery that can keep the speakers going for around 15 to 18 hours or can fully charge your i phone5, two or three times.
The decive case is hand built using MDF which I found among the trash in the basement .I chose MDF as its easier to work with and finish and it wont come off in layers
The speaker consist of a 2 inch driver which I took out of a broken desktop speaker along with a 62 mm circular passive radiator .The passive radiator improves the bass to a great extent.
The total amount I had to spend was just 13 dollars (₹845).
Step 1: SPECS:-
1. 5000 mah battery
2. Bluetooth connectivity, 15 to 18 hours of play time
3. Works as a power bank
4. Battery level of the device is visible on the paired smart phone
5. Single 3 watt driver.
6. Single passive radiator design
7. Can fit inside most pockets.
Step 2: THINGS YOU WILL NEED:-
1. 3 watt speaker X 1
2. Battery charging module X 1
3. 3 watt amp ( PAM8430) X 1
4. 2200 microfarad capacitor X 1
5. 3.7 volt, 5000 mah lithium polymer ( or more) battery X 1
(18650 batteries can alco be used)
6. 62 mm passive radiator X 1
7. Bluetooth audio reciever board X 1
8. 3 position slider switch X 1
9. 5 volt usb step up module X 1
10.5mm laminated MDF board
11. 20mm MDF board
12. wood glue or super glue
Step 3: TOOLS REQUIRED:-
1. Hand saw or a jig saw
2. A hand held rorory tool along with engravign and sanding bits .
3. A drill along with small bits , hole cutting and straight cutting bit .
4. Screw drivers.
5 . Hand file and small triangular file
6. Smooth finishing sand paper
7. Hot glue gun.
8. Soldering iron
9. Wood glue.
10 Cello tape
Step 4: CUTTING OUT THE BASIC FRAME:-
1. The first thing to do is to arrange all the components so that you would get a rough idea of the dimensions of the frame .
2. Draw the frame on a 20mm MDF board as seen in the second picture.there should be atleast 6mm gap between the inner and outer rectangles.
3. Cut out the piece using a hand saw or a jig saw.
4. Drill 4 holes on all the corners of the inner rectangle.This makes it easier to cut out the inner triangle using a jig saw or a cutting bit .
5. Once the frame is cut out, file the inside just to even out the surfaces and remove sharp splinters if any .
This dosnt have to be perfect as its not going to be seen from the outside
6. The outer surface need not be sanded or flattened now as this can be done in the end after sticking the front and back panel to the frame
Step 5: MAKING THE USB AND MICRO USB (charging) SLOT OPENINGS:-
1. The first thing to do is to measure and draw the usb and micro usb port openings on to the frame
2. For the usb port , first drill 2 or 3 small holes within the small usb rectangle , then shape it using the engraving bit untill the small triangular file can get in and then file the hole to the final shape.
3. Since the opening for the microusb slot is small , it can be entirely done using the engraving bit
4. Shape the openings untill both the modules fits inside their respective openings.
Step 6: MAKING THE FRONT PANEL:-
1. Cut out the front panel from a 5mm laminated MDF board using a handsaw or a jig saw.The size of panel should be that of the frame which was cut out earlier. Again , this dosnt have to be perfect as we will be sanding everything down at the end.
2. Draw a 52 mm diameter circle where you are palnning to place the speaker.If you have a 52 mm hole saw you can use that ,or you can use your rotory tool's board cutting setup to cut it out like I did .
3. Drill four 3mm holes around the speaker hole such that it matches with the screw holeson the speaker.
4. Cut out the hole for the passive radiator by the same ways mentioned above . Since I had a hole saw that was the size of my passive radiator , i used it for my second hole
5.Using the engraving bits, create an opening for the switch you are using like seen in the pictures.
6. You can also drill very tiny holes for the indicator lights using the smallest engraving bit.
Step 7: THE BACK PANEL:-
1. For the back panel , cut out a piece of the 1mm laminate .
2. Stick it to the frame using super glue or wood glue.
Step 8: ATTACHING THESPEAKERS,PASSIVE RADIATORS AND THE SWITCH TO THE FRONT PANEL:-
1. Stick the switch on the opening created for it using super glue and cover the sides with hot glue to ensure the box will be airtight in the end .
2. Stick the passive radiator using any rubber based adhesive like shown on the pictures.
3. Attach the speakers to the front panel using 3mm nut and bolts.
4. Again use hot glue to make the sides of the speakers airtight, make sure the glue dosnt touch the speaker diaphgram or the coil.
Step 9: COMPONENT PLACEMENT:-
1. Allign the charging module and the step up module with their respective holes and stick it to the back panel.
2. Use hot glue around the module and the frame to make the setup airtight.Be careful not to block the usb and micro usb ports ports.
3. Stick the battery and place the bluetooth module and amplifier according to the space available in your design.
Step 10: THE CIRCUIT AND WIRING:-
1. The wiring is done according to the given circuit diagram.
2. Test if the whole setup is working before closing up the box.
Step 11: GLUE THE FRONT PANEL :-
1. Stick clear cello tape from the inside over the holes you made for the indicator lights . This is to make the holes airtight at the same time allowing light to pass through.
2. Apply a thick layer of wood glue on the frame and place the front panel carefully on top of it allighning it correctly as much as possible.
3. Place a heavy weight on top of it. (I used a transformer)
4. Wipe out the excess glue with a cloth .
5. Let it dry for atleast 6 hours.
Step 12: FINISHING THE SIDES, EDGES AND THE CORNERS:-
1. Cover the speakers , passive radiators and the switch with masking tape or cello tape in order to protect it from dust while sanding.Then insert some paper inside both the ports to protect it as well.
2. Start sanding the sides with the rotory tool using a sanding bit.
3. Sand it untill you get a smooth, flat even plain .
4. Do this for all the 4 sides.
5. Draw a fillet design on the sharp corners .
6. Sand out the fillet on all 4 corners.
7. Finally sand the sides with super fine sand paper by hand.
8. Remove the tape and papers after clearing all the dust.
Step 13: STICKERING THE SIDES(optional):-
1. Apply strips of sticker on the sides
2. Cut out the portion of the sticker covering the ports using razor blade.
Step 14: AND ITS DONE :-
And just like that it's done While charging the light glows red .When it's fully charged it glows blue .
The present battery level will be visible on the notification bar of your phone once you have paired with the speakers.
If you guys have any doubt about the built, pleas do post it in the comments .
IF you guys like my instuctable, do vote for me
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