Introduction: DIY Mini Phone Speakers
Do you want to hear some loud music but the speakers in your phone are not loud enough to satisfy you? Don't worry, this project will solve your problem. The title of the project already reveals the mystery behind it but still briefly explaining it, it is a speaker with loud and clear voice and is small and slim that can be plugged in to your phone easily. It already has a male audio input jack which when plugged to your phone, provides support to the speaker so you don't need to hold the speaker with your hands or connect it using an aux cable. So why to wait, just build it plug it an enjoy it's loud music. Don't be fooled by its size. You will be amazed by the quality of sound it produces.
The project consists mainly of two LM386 amplifier circuits which is known for its low cost and good quality sound. It is powered using two 3v coin cells and has two 8 ohm, 0.3 watt speakers. You just need a little knowledge about electronics and a some experience with soldering to make it. It just takes 1-2 hours to make it so it can be a good weekend project. Not only your phone, but also it can be connected to an mp3 player, iPod and various audio devices.
You can even build my previous - DIY Travel Speakers project if you want to make a bigger version.
If you have any doubt related to this instructable or found an error, feel free to comment or ask a question. Do leave a feedback of the project and post you pictures if you've made one yourself or did a modification.
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Here are some features of this project:
- Has loud and clear sound according to its size.
- Is small, slim and lightweight thus can easily be fixed to your phone.
- No external cables required to plug it. Already has an audio jack.
- Is powered using button cells so no external power supply is required to power it.
- Is cheap to make. The total cost is around $4 which depends on the place you buy the parts from.
- Can be used in any audio device like an mp3 player.
Step 1: Parts and Tools
The following parts and tools are required to make this project. The total cost of the project was around $4 or 240 INR. All the parts can be obtained from your local hobby store or over online stores.
- 2x LM386 audio amplifier ICs
- 2x 8 pin IC sockets
- 2x 8ohm 0.3watt speakers
- 2x CR2025 coin cells
- 2x Coin cell holder
- 2x 10K presets
- 4x 220uf electrolytic capacitors
- 4x 10uf electrolytic capacitors
- 4x 10ohm resistors
- 3x 1K resistors
- 1x Toggle switch
- 1x 3.5mm Male audio jack
- Small drug case
- Thin wire
- Soldering iron
- Soldering wire
- Hot glue gun w/glue sticks
- Wire cutter/stripper
- Mini drill
- Insulating tape
- Double sided tape
- Marker or a pencil
Step 2: Prep Your Enclosure
The first step is to prepare your enclosure and making holes for all the parts. But before that you must choose the correct enclosure for your project. Since the speakers have to be connected to your phone and have to be supported by just and audio jack, your overall project including your enclosure should be small and lightweight. Make sure that the size is just sufficient for all the parts to fit in easily and should not be too small nor too large. The best option can be to use a small plastic container used to store medicines. They can be cut easily and are cheap. The dimensions of my enclosure were- 10 x 6.5 x 2cm but it can be varied according to your needs. You can even use different materials like wood and acrylic to make your own enclosure.
For preparing your enclosure, first measure all the components and mark them on your box using a marker. Finally drill all the holes. The major things you need to add are- speakers, switch, LED, audio jack and presets. You can also use a hot knife to cut a plastic enclosure.
Step 3: Prototype the Amplifier Circuit on Breadboard
The amplifier circuit used here is the same as the circuit used in my previous travel speaker project. It consists of an LM386 with some external filter components such as resistors and capacitors. Since two speakers are used in the project, there are two such circuits used. The need for such an amplifier is that the audio signals given out by your phone are too low to drive a speaker loudly and are just sufficient to power an earphone. Amplifiers are present in almost every speaker you see that is in your phone, TVs, stereo systems and even DJs.
For prototyping your circuit refer to the layout above and connect everything according to it. The reason why you should prototype is to check if the circuit works or not and do any modifications. Connect the audio jack to your phone and power the circuit with a 9v battery (or any power supply between 5-15v). On playing a music on your phone, if you hear a loud sound coming from the speaker, that means you have done it alright. If it doesn't, check the connections and try again.
Step 4: Solder the Circuit on Perfboard
After prototyping your circuit, solder the whole circuit according to the schematic given above. The best way to solder is to use a perfboard however you can etch your own circuit board or use a copper strip board.
Start by soldering the IC socket first and then all the components. Cut off the excess PCB using a pair of scissors. The need for an IC socket here is to prevent overheating and malfunctioning of the IC when soldering it.
Step 5: Connect Your Speakers
For connecting your speakers, first glue them to the holes that were marked earlier and solder two pieces of wires to each one of them.
Finally connect them to the circuit following the schematic given above. Make sure you connect both of them with the correct polarity.
Step 6: Connect the Battery, Switch and Power Indicator
The power supply used in this project consists of two 3v coin cells connected in series to produce 6v which is enough to power the circuit. The reason that I didn't use heavier and bigger batteries was that my enclosure was small and there was hardly any space left in it for the battery. Li-po battery was also not used here as it can give only 3.7v while LM386 requires atleast 5v to operate so there would be a need to add two of them which would eventually cost more. However if you wish to modify your project, you can use any power supply/battery between 5-15v.
I added a switch to easily switch the speaker on and off which would not require removing the batteries again and again. First solder both the holders on a piece of perfboard and connect the positive terminal of first holder to the negative terminal of the second. Then connect the positive terminal of the resulted battery pack to pin 1 of your switch. Connect the negative terminal of battery pack directly to the gnd of the circuit. Finally connect pin 2 of the switch to vcc of the circuit.
Step 7: Add an Indicator LED
A power indicator LED is added here to prevent you from forgetting that your speaker is left on overnight which will result in draining out the entire battery. Connect a 1K resistor to the LED and then connect the positive leg of LED to vcc of the circuit and negative leg to gnd.
To check your wiring, add two batteries to the holder and switch the speaker on. You would see the LED lit up.
Step 8: Add Volume Control Presets
To add a feature of volume control within the speaker, I added two presets to control the volume of each one of the speakers. The reason why I used preset instead of a potentiometer was that the enclosure was quite small and there was a little space left. The connections were already messy which made it difficult to add them.
Connect your preset according to the following:
- Pin 1 ---- Unconnected for now (will be connected later)
- Pin 2 ---- Pin 3 of IC1
- Pin 3 ---- Gnd
- Pin 1 ---- Unconnected for now
- Pin 2 ---- Pin 3 of IC2
- Pin 3 ---- Gnd
Finally glue the presets to the enclosure to the hole that was made earlier.
Step 9: Glue and Connect the Audio Input Jack
This the last step to complete your project. To connect your speaker to your phone, there has to be and audio jack to plug it in to your phone. For this project, I chose that the audio jack would be glued on to the speakers with no external wires and would be the only support of your speaker while it is connected to your phone. This would cancel the need of holding the speakers with your hand while playing music.
For connecting the jack, first connect it to the circuitry according to the following connections:
- Sleeve (common) ---- Gnd of circuit
- Ring (right) ---- Pin 1 of preset 1
- Tip (left) ---- Pin 1 of preset 2
Finally glue tightly the jack to the hole that was made earlier. Make sure that it doesn't come out even on pulling it.
Step 10: You're Done!
So you're finally done making your own phone speakers. Just connect the batteries, raise the volume and enjoy the music whether it is calm or loud. This concludes this instructable as well. Hope you liked it. If you have any doubt related to this project, feel free to comment or ask a question. Do post the pictures of your project if you made one yourself or did some modifications. Any suggestions are welcome. Here are some modifications you can do to make your project even better.
- You can make the enclosure slimmer and smaller by using small components and using readymade dual amplifier circuits that consist of SMD components.
- You can use a different power supply like a 9v battery, li-ion or a li-po battery. You can even use an external power supply.
- You can experiment with different speakers to make the sound quality louder and better.
- You can extent the audio jack with a wire to easily connect it to your phone.
- You can paint your enclosure to make it look even better.
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