Hi friends... When I've decided to learn how to play piano, I searched in the YouTube,and found tutorials and downloaded a piece by Dmitri Shostakovitch (Waltz No 2), which I recommend listening to it (for those who haven't listened to it ) and sat down on the stool of the piano and tried to play, but I quickly realized that I needed to refer to the tutorial repeatedly while I was playing the piece and I thought if I had Bluetooth speakers to connect to my cell phone by wireless Bluetooth that would be fantastic, so I decided to make one but small one which could be put on the piano top with, then I made that and now I am going to explain how I did that.
I had five important goals in making this amplifier which are as follows:
1- Being cheap
2- Being small
3- Easily repairable
4- Easily Chargeable
5- Being portable
This kind of Bluetooth speakers are everywhere and you can find their circuits in many sites including Instructables and making that is not a difficult task but perhaps the most interesting part of the present amplifier is, its power supply is virtually free of charge because use has been made of laptop discarded batteries which are great batteries that makes it portable with a long charging life. Ease of repair comes when you make the housing, which I made it with two sides of that sliding and by removing these two sides everything would be accessible and repairable. Being small is the length of edges are just 13 Cm that is just enough for the loud speakers to be fit in the side, and lastly cheapness comes for the cheap parts used in it and the total price of it has become just $ 10 which is pretty cheap.
Step 1: The Circuits
There are two circuits in this amplifier:
1- The Bluetooth circuit
2- The blinking strip diodes circuit
Both of these circuits were copied from previous works of others but I did some modification in both of them, in blinking diode circuit I changed the power supply to 12 V and the R3 and R4 resistors to 100 k and I have use strip diodes for better light and smarter appearance. In Bluetooth circuit I have used PAM8403: https://www.win-source.net/en/search?q=PAM8403 , and used BT163 Bluetooth receiver.
Step 2: Materials and Parts
The list of materials and parts are as follows:
1- Bluetooth speakers:
- One PAM8403 :
- One, Bluetooth receiver, BT163
- Two, speakers, 3 W and 8 Ohm each
-One, Audio jack
- One USB female for BT163
- One, rocker switch
-One, small perf. board
- Two, 2 -Pin Cable Wire Terminal Connectors
- One 8705 regulator IC
- Enough wires
2 - Blinking strip diodes
- Two, 10 Cm rigid strip diodes, One red, One green
-Two, 100 Ohm resistors
-Two, BC547 Transistors
-Two, 100 k Ohm resistors
- Two, 10 uF electrolytic capacitors
- One, rocker/toggle switch
- One, small perf. board
-Two, 2 -Pin Cable Wire Terminal Connectors
3 - Batteries for both of the above circuits, three 4 V batteries taken out of a discarded laptop battery and soldered in series to make them 12 V
- A power/ charging jack
- Five, 13 Cm * 13 Cm pieces of poly-carbonate sheet 6 mm thick
- Two, 13 Cm * 13 Cm PVC sheet 3 mm thickness ( i have used two of these sheets for top side)
- One handle ( I have used a spare kitchen cabinet door handle)
- Two pieces of 12 Cm* 12 Cm wire mesh screens with small mesh ( As speakers protective cover)
- 300 Cm of electrical duct with 1 Cm width ( for edges of cube sides)
- 8 screws with nuts for fixing speakers and 4 screws for fixing perf boards to bottom side of the cube.
Step 3: Tools and Related Materials
Tools needed for this project:
1- Soldering Iron and solder
4- 10 Cm Circle cutter
Step 4: How to Make It
1- Bluetooth circuit should be implemented according to the instructions as follows:
Now take the PAM8403 and solder its terminals as follows:
- Left speaker + wire should be soldered to the + mark of left speaker on the PAM board
- Right speaker + wire should be soldered to the + mark of Right speaker on the PAM board
- Two wires should be soldered to 5 V terminals of PAM board and the other sides of them to 5 V terminals of the perfboard
- An audio jack should be soldered to L, G, R of the PAM board - A female USB should be taken and two wires should be soldered to + and - pins of that, and these two wires should be connected to 5 V of the perfboard terminals( so two wires should be connected to + and two wires to - terminals)
- The Bluetooth should be connected to audio jack and female USB - The Bluetooth circuit should be inserted in to the container and speakers should be put in appropriate place(holes were already made on two sides of the empty cream container)
2- Blinking diode circuit should be implemented the same way as the amplifier part,i.e. first on a bread board and then on a perfboard, there is not much difficulty here but the transistors should be soldered in a right way other wise it doesn't work properly, again test this part by in both stages i.e. bread board and perf board.
3- making the housing by first making edges by using electrical ducts as if you are making a photo frame and insert those poly carbonate sheets in to the frame and glue them together, for speakers you need to make holes with 10 Cm diameters on two of poly carbonate sheets so to be able to attach the speakers but before that you should install the wire meshes in place. be careful to glue sides in square way to make 90 degree angle between sides. Glue all sides except the front, back and top sides,make appropriate holes for switches, audio jack and charging jack on the front and insert those parts in place and glue them correctly then glue two 10 Cm rigid strip diodes in place on the front side Then screw down both perf boards on the bottom side and leave the assembly aside for next stage. Now you have a cube with two sides not built back and top.
first make a U shape frame from electrical duct and glue them in place to the existing frames and then glue a piece of electrical duct to one side of the last poly carbonate sheet and then insert the sheet in to the slots of the U frame attached in place.
The last part is the top side, first make a U frame out of electrical duct and then glue them on the top to existing frame and then insert the first PVC sheet in to the slots, then attach the door handle to the top PVC sheet and insert in in to the slot to make a tight connection.
If you have thorough look at the photos you can easily find the way to do that unless you use other methods or other materials say wood sheet etc etc
Step 5: The Testing and Enjoying Step
In this step you can test the assembly and enjoy it, try to charge it and see the result.
Hope you like this project and make it for yourself or your friend.
Thank you for your patience