Introduction: How to Make DIY Speaker
For people who don't want to go out to the store and buy a brand new speaker for home-use, this is a perfect project. The cost is very low and the procedure is also very simple. It is always a very exciting feeling to watch your self-made speaker play songs that you love.
The final product is also very aesthetically pleasing as you can reuse and imaginatively spray paint its body. All in all, this is a very easy project with a very useful outcome. I use my speaker regularly: every time I am building something or working on a project.
1) 2 x 3W/6W Speakers
2) 1 x PAM8403 audio amplifier board
3) 1 x 3 output audio jack
4) Multicore wire for connections
5) 1 x SPST on/off switch
6) 1 x LED (optional)
7) 1 x Soldering iron
8) Soldering wire
9) 1 x Junior hacksaw/coping saw
10) 1 x Hand powered drill or electric drill
11) 4-5 AA batteries (Ones lying around at home can do)
12) 1 x 6V AA battery pack (4x AA batteries)
Step 1: Getting the Components for the Circuit
All of the items can be purchased on amazon. You can find the links to some of the better options available online.
1) 2 x 3W Speakers - https://www.amazon.in/PAM8403-Digital-Stereo-Ampli...
2) 1 x PAM8403 audio amplifier board - https://www.amazon.in/PAM8403-Digital-Stereo-Ampli...
3) 1 x 3.5mm 3-connector male jack - https://www.amazon.in/NextGeekTM-Repair-Headphone-...
4) Stranded core wire for connections - https://www.amazon.in/Aayaam-Technologies-Single-B...
5) 1 x SPST on/off switch - https://www.amazon.in/Generic-10Pcs-Mini-Terminal-...
6) 1 x LED (optional) - https://www.amazon.in/LED-Pack-Basic-Ultimatum-200...
7) 4-5 AA batteries (Ones lying around at home can do)
8) 1 x 6V AA battery pack (4x AA batteries) - https://www.amazon.in/MA-Plastic-Battery-Storage-s...
Step 2: Circuit Explanation
The circuit consists of 3 parts, the input from the phone, the audio amplifier processor, and the output speaker.
Understanding the audio connector
The audio connector has 3 outputs which are all insulated from each other using the black strips. The three outputs are ground, left speaker, and right speaker. This is to help you fully experience songs like Bohemian rhapsody where each speaker would play a different sound.
You may also find audio connectors with 3 black stripes (4 outputs) in earphones. The additional output is for giving a signal to stop, play, or change volume to the phone/laptop. And there are also ones with only 2 outputs (one black strip) that don't provide a differentiation between the left side and right side.
Why is the audio amplifier necessary?
The phone's audio jack's output is at a relatively high impedance while the speakers have a relatively low impedance. Therefore you were to connect your phone directly to a speaker, without an audio amplifier, it would spoil the phone's internal circuitry. The speaker will try and draw way too much current from the phone and there won't be enough voltage to power the speaker. That is why we need an audio amplifier. To provide the right intensity of current to the speaker. You can see that the audio amplifier is also connected to a 5V battery source. It draws current from this to power the Speakers.
Good website for explanation: https://www.headphonezone.in/blogs/audiophile-guid...
How do speakers work:
There is a permanent magnet and a copper coil present in the speaker. The signal from the phone, which passes through the coil, induces a magnetic field that changes rapidly. This induced magnetic field interacts with the permanent magnet (like charges repel...) and creates vibrations in the form of back and forth movements. These movements when taking place fast enough with sufficient force produce audible sound. The faster the vibrations, the higher the pitch.
Link for additional explanation: https://blog.landr.com/how-do-speakers-work/
Step 3: Soldering Speaker to the Audio Amplifier
1) Start by soldering the speakers to the audio amplifier. There is a positive and negative on the speaker as well as the board. Match the polarity.
2) If you can't figure out which one is positive and which one is negative check out this link.
Just a note, make sure to not press the dust cap as it will go inside and ruin the look of your entire speaker. You will not be able to pull the dust cap back out. I accidentally did this to my right speaker and now it is messed up permanently.
Step 4: Soldering Battery and Switch Into the Circuit
Connect the battery and switch in a series circuit.
One terminal of the switch connects to the positive end of the battery.
The other end of the switch connects to the positive input of the audio amplifier board.
The negative end of the battery pack is connected directly to the audio amplifier board.
You can also add and optional LED to indicate that the switch is on/off. The LED would also be connected in series.
Step 5: Soldering the Audio Jack
This step is a bit tricky especially if you are not familiar with soldering. You will have to be very patient with this step as you have to make sure no wires touch each other in the audio jack.
There are two ways to do this, one is more challenging than the other however it has a better finishing look.
1) Cutting and using old earphone wires. They have all 3 wires within one and it looks a lot better in the end. I would recommend trying this if you are familiar with soldering. You would have to cut the wire first to expose its insides. Separate the 3 different colors of wires, usually red, blue, and copper. The copper wire is the ground. The other two can be switch around it doesn't really matter.
2) The other option is to get 3 long pieces of wire and attach them separately and then join them together using heat shrink.
For soldering the wires onto the audio jack, follow the image. The longest leg in the audio jack is the ground and you would be soldering the copper wire if you have chosen case 1. Then the left and right speakers. Make sure you remember what color wire is connected to which pin in the audio jack as you will have to make sure you correct the right wires to the right inputs for the audio amplifier.
Step 6: Testing the Circuit
If you have soldering everything correctly then you would have a working circuit now. You should be able to connect your phone to the audio jack ad start playing music if you have turned on the switch. There is no other set up required.
Step 7: Music
Testing the speaker with two songs. Let me go and Dancing in the moonlight
Step 8: Housing Options
There are a lot of different options you have for housing.
1) Leaving the circuitry as it is without any housing.
2) Laser cutting a box out of MDF or acrylic
3) Using pieces of spare wood to make.a box
4) Using a preexisting box/container and make the necessary holes in it for the speaker.
I did the last method as I had a very nice box given as a container for sweets during a festival. Therefore all I had to do was cut holes in the box using a hacksaw, knife, and scissors. I also had a bit of corrugated sheet which I then spraypainted to cover up any blemishes from trying to cut the speakers' holes.
The box had come with a hinge already allowing me to open it and close it with ease. I added a box buckle on the top to help keep the speaker closed during use. The sound is louder and better when you close up the back.
I did not have a hole for the switch as I didn't think it was necessary. And it would also ruin the aesthetic of the speaker.
Finally, using a hand-powered drill, I made a small hole in the back for the audio jack and its wire to pass through. All the circuitry was inside the box.