Introduction: Make a Speaker Inside a 9V Battery
There are a lot of instructables stating how to make a speaker. Those speaker can be as tall as you and can be as small as your palm. But can you ever imagine that you can make a speaker inside a 9V battery. I know that it sounds weird but it's actually possible. You can make a speaker with decent amount of loudness and intensity inside a 9V battery. The idea of making this tiny speaker came to me from a bunch of old batteries. I had a bunch of old dead batteries lying around and was trying to use them in some way or the other but finally ended up with throwing them in the trash. I took a 9V battery and started thinking what could I make with this thing. Suddenly I got an idea of making a speaker with a 9V battery and rather power the speaker with the battery, I decided to make a speaker inside the battery. Since I had all the required materials and tool, I started making the speaker.
So let me tell you a little about this speaker or battery or battery speaker or ???? You decide what you want to call it. This speaker has a PAM8403 amplifier board. Those board cost around $2 and are really efficient in amplifying the sound. Making a DIY amplifier would not be a good idea as there is not much space inside a 9V battery to fit in those heavy amplifier ICs. The speaker used by me is an old mobile phone speaker. You can get those in mobile phone shops as well as in ordinary speaker shops. Coming upon the connectivity, this speaker connects to your phone using a AUX cable. I was not able to hook up a Bluetooth module inside that tiny beast. You have to power this speaker from an external power supply. I used those connector to supply power through which we used to drain energy from our 9V battery earlier. The voltage on which amplifier board works the best is 5V. But you can also use 3.7V lithium ion cell to power the speaker as I did. The speaker sound great and looks cute too. You can show it to your friends and colleagues and they will definitely be astonished after seeing this speaker.
Here is a 6 min video on how to make a speaker inside a 9V battery:
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Step 1: Gather Parts
So here is the part list. This project requires very less items to build so you need not to worry about the expenses:
- An old 9V battery
- A small amplifier(I used PAM8403)
- A small speaker(Can take out speaker of old mobile phones)
- Female audio jack
- A 5V power supply
- AUX cable
- Soldering iron
- Dremel with necessary bits
- Hot glue gun
Step 2: Disassembling the Battery and Marking the Speaker Holes
We'er gonna start by disassembling the 9V battery or more appropriately opening the battery. You need to get all the stuff out of the battery. The chemical occupying most of the space should be take out. We only gonna need the outer covering of the battery, upper connector and the bottom plate. Start by taking a sharp knife or a screwdriver. Make sure to be safe while using the knife. With the knife open the uncurl the curled part of the metal holding the down plate. You can use a plier also. Make sure you don't break to bottom plate. After you are done, apply some pressure on the connector plates and the chemical of the battery wrapped in plastic foil should come out. Pull it out and throw it in garbage. Use plier to fix the body of the battery.
Now take your speaker and using a marker, mark its outlines on the body of the battery. Make sure you use a permanent marker otherwise your marked outlines would fade away and it will be difficult for you to cut the metal body. Using a dremel cutting tool, cut the body precisely. I found that my dremel tool was not much efficient in cutting the body so I used sharp knife to cut it which worked awesome. At last I used metal sheet cutter for a better detailing. After cutting is done, use a sanding drill to make the hole look better. You can easily tell by looking at the images that I am not good in sanding but that much sanding worked fine for me.
Step 3: Connecting Speaker to Amplifier Module
As you guys can see I used a ready-made module for this project. First I though to make a Amplifier board for the speaker but then I realized that the ICs I will be using are too big as compared to a 9V battery and they along with capacitors would eat up all the space. I had this amplifier board lying around from a while which I purchased a couple of months ago for around $2 and found it to be a perfect match for my project. The performance of the amplifier board was awesome and it could easily fit in inside a 9V battery. Though this amplifier board can power up two speakers, I decided to use one speaker to save space.
Now lets get back to the project, start by connecting the 5V and ground of the amplifier to negative and positive of the 9V battery connector(the one that we took out in previous step) respectively. Further connections are listed below:
- Sleeves of female audio jack-----ground
- Ring of female audio jack-----Right input channel
- Tip of female audio jack-----Left input channel
- Negative of speaker-----ground
- Positive of speaker-----Positive of Left and Right output channel
Step 4: Fixing Everything Inside the Battery
Our circuitry is ready now and its time to fix everything inside the battery. The best way is to use hot glue but you can also use super-glue. The first thing which goes inside is the connector that we are using as the power input for the amplifier. Hook it on its place and hot glue. When I was sticking it with the battery case, it was again and again coming out of its place so what I did was, I pushed it to its place using my finger and quickly dropped few drop of hot glue on the outer part. Once it was fixed on its place, I applied adequate amount of hot glue to the inside body and the removed the hot glue was sticking outside.I know that it is bit confusing for you guys. Then pour some hot glue on the back of the amplifier board and quickly stick it inside. Don't forget to apply hot glue on the connection of the amplifier board so that they don't get shorted from the metal casing. The fix the speaker. As you guys can see, my speaker is popping out from the battery a little bit. This type of speaker arrangement has two disadvantages. One is that you can probably damage the speaker while using it and the other one is that the sound or audio you will be hearing would be faint so try to stick the speaker as deep in the casing as possible.
Now for the bottom part, you must be having that plate covering. But before we fix it, we would be drilling a hole in it for the female audio jack. Choose a drill bit which is of the size of your audio jack and drill a hole with it. Mount your audio jack using hot glue and finally apply the plate on the bottom part of the battery and completethe enclosure.
Step 5: Testing
This is the time to test our speaker and see whether it is working not. So start by connection the power supply to your speaker. By the way the amplifier of the speaker works on 5V so you should have a 5v power supply. In my case I used a 3.7V 3000mah li-ion battery which worked perfectly fine with the speaker. I connected a 9V battery clip to the cell to easily attach it to the speaker. According to our connections, the negative of the battery clip goes to positive of the cell and positive of the clip goes to negative of the cell. Connect the battery to the speaker and connect your speaker to your phone using a AUX cable. Play any random song from your mobile and speaker should work perfectly fine. You can control the volume of the speaker using your phone's volume rockers since we didn't attached an external volume controller to the speaker. I you want to check the audio quality of the speaker, watch this video. You can simply fat forward it and find a clipping at the end of working of the speaker.
Step 6: The End
Guys this is the end of this project. Hope you liked it. Show this battery to your friend and relative and have fun. Don't forget to follow me on instructable and subscribe to my YouTube channel. Here a link of the video. Please go and watch it. As always meet you next time. Happy making;)
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