Make You Own Hands Free Car System for Your Phone.




About: I am obsessed with making new things, my mind is always working. and if i dont have the right tool ill make it. i was the kid that would take my dads tools apart just to see how they worked. I have been dubb...

Do you have an older car that does not have those fancy hands free systems, that let you talk on your phone and have it play through your stereo system while driving? Or do you have one that for some reason does not seem to work with your phone no matter how many times you take it to the dealer and your cell phone company? Well with this simple and very cost effective hack, those problems are problems of the past.

Let me introduce myself, I am a tinkerer and have been for as long as I can remember. Growing up we weren’t the richest family on the block, so when I would think of things to make I had to find ways to get the parts for free or next to it. I have kept that way of thinking, so all of my inventions have as little of cost as possible. I like to share my ideas, and like it when everyone can enjoy and even improve on them.

I would also invite anyone who can improve on them please feel free to do so. I know not everyone has access to the exact supplies that I have so please feel free to improvise as long as the end result works the way you wanted it to you succeeded.  I like for my ideas to be a base. I invite, no encourage people to improve on them and make them better. After all we are all makers here, if I can make my idea good for you I know someone else cal make them great for the next maker.  

Ok enough talk let’s get to making your life a little bit easier.

Step 1: Materials Needed

I have an older car “05” and I wanted one of those hands free devices for the car that let you talk on the phone and have the sound go through the car speakers. I don’t like the Bluetooth ones that you put on the visor.  Listening to my friends that have a newer model car that has that system built in, they have to find a phone that is compatible with the blue tooth, or plug it into the pre installed USB. Most of them had nothing but complaints that they had a hard time finding a cell phone that was compatible with the Bluetooth of their car, or said that the USB was far from being completely useful. Os I began to try to think of a solution that would benefit me and help out my now very annoyed friends. This is what I came up with; it’s a simple hack of an IPhone headset.

You need a couple of pre-requisites first though:

1.       Cell phone compatibility- You need a cell phone that is capable with a wired headset that has a microphone (such as IPhone).

2.       Car compatibility- you either need a radio with an auxiliary 3.5mm headphone jack or a car that comes with one installed somewhere else on the car.

3.       The next pre-requisite is a very easy one for every one- little to no money (assuming you already have the tools)

All of us have number three, but the first two you kind of already need to have although the radio with the jack needed are very reasonable( if you’re in the market)

Complete materials needed:

1.       A radio with a aux. 3.5mm jack or one installed on the car somewhere

2.       A IPhone headset with a microphone (I am using the newer one with the volume controls on the headset if yours doesn’t have the volume controls then you are using the older model headset)

3.       A audio jack( I got mine off old computer speakers)

4.       Small gauge wire(I’m using the microphone from the same computer just taking the wire and discarding the jack)

Tools needed:

1.       Wire cutters ( I just used scissors)

2.       Wire stripper (my teeth)

3.       Soldering iron

4.       Solder

5.       Electrical tape


Step 2: Opening the Microphone.

To take apart the microphone of the headset you need to pry off the front and back casing. You need to be VERY careful when prying off the casing. The circuit board is very brittle and if you bend it too much it will break, try to keep it as straight as possible.

 The front is easy; just pull your nail in the crack on the side to pry it off. The back is very difficult it has several plastic tables that are welded to the middle. Take it off piece by piece till the board finally comes out hopefully in one piece.

Now that you have the board away from the plastic casing, desolder the 2 joints on the end of the tiny board. Don’t leave your gun on them to long or you will damage the board. Tap the soldering points with your gun with slight pull on the wire and they will come right off.

Place the board in a safe place, I accidentally dropped mine on the carpet and it was like I lost a contact.

Step 3: Prepare Your Wires

By now your probably noticing that we are dealing with coated wires. If you are unfamiliar with these type of wires they are coated with a form of enamel, and are difficult to solder. Its ok, take a deep beath we will get hrough this.

First you have to expose your wires. Cut off the speakers right underneath the little triagle thing in the middle of the headset. Then take off the white rubber coating. There should be  6 wires, if you only see 5 its because the 6th one is hidden inside inside the wire that’s red and green. Un twist the red and green wire and viola there is the 6th wire. strip off the coating of the 6th white wire. Now that you have all 6 its time to check the lenth.

Step 4: Check Wire Length

Now would be a good time to check the length of your wires to see if your wires are long enough. 

Run out to your car and determine where you want to put the microphone. I wanted mine right behind my steering wheel. I have an IPhone 4s and I still wanted access to the home button because if you press and hold it you can still have access to Siri. Unless you’re in NASCAR, I find that I don’t turn enough for the steering wheel to be a real bother. If you don’t want this function, or don’t have it, all you would really need to use is the microphone. If that all you need you can easily hide the tiny board.

I had to take apart my dash because I wanted to run the wires behind it. Only do this if you feel comfortable with it. If not the wires are small enough to where I’m sure you can find a way to hide them on your car.

You want the microphone to be in front of you so that you don’t have to yell for the person on the phone to hear you.

If you have to, extend your wires, if not then please follow me to the next step

Step 5: Tinning Your Wires

I made a separate step just for tinning, because a lot of people have problems tinning these types of coated wires. Unfortunately they are becoming more and more common. Now it’s time to tin all your wires.

Tinning these types of wires is relatively simple. First step is these wires come with some type of white, what look like to be string, in the middle of them. Unwind the wire and take all this string out cut it off then wind the wire back up again. You don’t need to take it out of the entire wire just the part you are going to solder. Leave your soldering iron on and let it get good and hot. Pre tin the tip of you iron, and flux your wires. Now that your iron is hot and your wires are fluxed just try tin them like normal. Run the wire through the melted bead of solder on your iron. If you have a hot enough iron this will work if you don’t have an iron don’t worry you don’t have to go out and buy one. You just have to do it the other way.

What’s the other way? Glad you asked. The other way to tin these wires is to get a stack of 5 plain white sheets of paper and put them on a hard surface. Flux your wires and pre tin your gun. Then put the wire to be tinned on the sheets of paper. Put your iron bead down on top of the wire and apply a little bit of pressure. You’re going to make a wire sandwich where the paper and iron is the bread. Then run your iron to the tip of the wire. Congratulations your wire should now be tinned. Start of the base and work your say to the tip you may have to do multiple runs to get a good tinning. You’ll probably see the color coating along with burn marks on the paper like the one of the picture. Mine was green

Now that you are professional at tinning these wires, put your new skills to work, and do it to the rest of them. Just remember to take out the middle white strands before you try to apply heat.

Step 6: Connecting the Wires

Now that all your wires are tinned it’s time to connect them. Take you wire that you made from the IPhone headset and the audio jack from the computer and connect them together.
I said to use an audio jack because most of them have a right positive, left positive, and a right negative and left negative. If yours only has 2 wires then its mono which means you only have one wire for right/left positive and one wire for right/left ground. What does all this mean? Well have you heard the songs on the radio that only come out of one side of your car at the beginning, then through all your speakers later on in the song. Well that’s an example of right positive, left positive, and ground (4 wires). Now take that same song and play it through the 2 wire system and it will play through all your speakers throughout the whole song. Honestly unless you’re an advocate you won’t even notice. Me personally I just want to hear my music.
Ok now you’re going to take your IPhone headset wires and connect them like so:

2 gold are right left negative solder them together and to the ground on your audio jack (mine are silver yours may be black)
Solid Red is right positive connect that to one of the positives on your audio jack. Solid Green is left positive connect it to the other positive on your audio jack.  It really doesn’t matter which one, any positive will do. Worst case scenario is you get it backwards and what was meant to come out on the right side of your car now comes out on the left side. Are you really going to notice? If you are then make sure you figure out which one is the right side. Trust me its more work than it’s worth. Save your grey hairs for something that really matters.
I didn’t forget about the ones that are using a 2 wore audio jack. You are going to want to solder the solid red and solid green together, and solder them to the positive on your audio jack. Then solder the 2 gold wires together, and solder it to the negative on your audio jack (usually black).

The microphone on the IPhone is red and green coiled together it kind of looks like a Christmas wire. The microphone wire off the microphone of the computer, conviently has only 2 wires, exactly the amount you need
Now remember I told you to put the tiny board in a safe place? Well by now you probably forgot which wire goes where on the board, well don’t worry I got you covered. First connect the Christmas wire to one of the 2 wires and the gold one to the other just remember which one you connected to which. In my picture the Christmas wire is connected to the green wire and the gold is connected to a gold wire. Strip and tin the other side of the computer microphone wire or whatever wires you are using to extend it, if you haven’t done it already, this side is going to the board. Now place the board with the buttons away from you, and the microphone up. The soldering point to your left is going to be where you connect the wire you connected to the Christmas wire and the soldering point on the right is going to connect to the wire you connected to the gold wire

Step 7: Finishing Touches

Now that everything is connected, all you have to do is make sure the joints don’t touch and make it pretty. Try it out before you install it in your car. plug everything in and see if the other person can hear you. This is also a good way to find the ideal spot to place your microphone.

I put electrical tape to keep the joints separated but that’s because I hid mine behind the dash board. Feel free to use whatever method you like, as long as the joints don’t touch your golden. I also cut off the green rubber on the jack that was to connect to my radio. I didn’t want a big green thing sticking out, and grabbing possible unwanted attention. If you decide to do this, be careful some of them are glued to the wire, and are hard to come off.   Then I put black tape to keep the wire from dangling straight down.
I also grabbed some of the squishy stuff that keeps your drawers from banging, cut a small piece, and glued it to the middle button. I wanted to make it easier to press so that I can still use Siri. Then I glued the microphone right behind the steering wheel. I plugged in the audio jack to the aux. Jack on my radio. Plugged in my IPhone to the headset jack, and tried it out. I gotta say if you have an IPhone and use Siri it kinda feels like you’re talking to K.I.T.T. from Knight Rider.

All done!

It was a pleasure making this for you guys. Please feel free to improve on this idea; I am excited to see what others come up with. If you run into problems please feel free to message me and I will help in any way possible.
See you next time

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    11 Discussions


    2 years ago

    Hey guys I don't get it. There is a company called Blitzsafe that makes this stuff. No need to reinvent the wheel.


    3 years ago

    Question: can we connect multiple mics to gain better coverage inside the car? How do we do that if possible?


    3 years ago

    Why don't you just cut the earphones and "reconect" all the wires into one jack?


    7 years ago on Introduction

    No audio jack on the car radio, use a wireless FM transmitter. Second, a question...if a radio has a audio jack, mine does not, if you plug a jack in there, does it cut off the speakers automatically in the car? I would assume the jack is for a MP3 player or such. If you plug an MP3 player in, does it not just cut the radio off , and just play the MP3? And my thinking is if you plug the iPhone into that jack does it not cut the sound off from the radio. Or, does it just cut off when a signal is input to the jack??? I assume you are leaving the audio jack mod in all the time. Any info would be nice, thanks!!!


    7 years ago on Introduction

    This would work even if you didn't have an Aux jack, right? I am thinking that you could get away with a tape deck and a tape to 3.5mm converter like this one:

    And then all you would need to do is use the cassette adapter wires where the instructable says to use "audio jack" wires.

    Anybody seen an issue with this?

    2 replies

    Reply 7 years ago on Introduction

    i haven't done the modification to add the microphone, but i listen to audiobooks during my commute to and from school. They're stored on my (Android) phone and i use a cassette adapter to play them through the car stereo. If my phone rings, the ringtone and the caller's voice come through my car's speakers. (TIP: Turn down your phone's ringer volume before plugging in. Otherwise the ringtones are unbearably loud.) i'd like to try adding a microphone to that setup...

    Thanks for an inspiring 'ible, scion6tc!


    Reply 7 years ago on Introduction

    Ya in theory that sounds like it would work but the only way to know for sure is to try it out. I would first try it on some older headsets just to make sure.


    7 years ago on Introduction

    To clarify, you cut the iPhone headset right below where the mic module part was located? Also the iPhone plug goes into your phone, and the black plug goes into the aux? While all the electrical stuff is hidden behind the dash? Could you post a picture where I can see how it looks to see how well it's hidden? Thank you for posting this tutorial I found it very interesting and hoping I'm going to be able to do it!
    My main concern that is preventing me from starting this today, is how loud my exhaust came when I bought my truck and that this mic will not be able to pick my voice up over the exhaust.

    2 replies

    Reply 7 years ago on Introduction

    I to have a loud exhaust and was worrried that this would not work. The best way that I found to check the levels was to plug a headset into your phone,grab some tape, and place the mic roughly where you want it just be careful not to cover the mic opening. Drive around and make some calls, but I would also turn on your ac or heater full blast or roll down the windows to check the addes noise of the air. Whatever you normally do while driving. If the person cant hear you on the other end dont worry just move the mic around the car. Dont be afraid to get creative of where you place it the mic, it is surprisingly sensitive. Which reminds me keep in mind if you are going to take the casing off the mic it will pick up more residual noise but it will also be able to pick up your voice better. I will try to post some better pictures for you within the next couple of days.


    Reply 7 years ago on Introduction

    You can test the exhaust question by finding a way to attach your phone to the steering wheel and driving around and calling friends to check on the noise level.

    On my truck I have a level surface behind the steering wheel so I could attach mine there but I do not have a very loud exhaust.


    7 years ago on Step 5

    i faced the same issue with the coated strands of wire. a quick google gave me the solution to flame it. take a match or a lighter light the tip. in a few seconds the flame will travel backwards. just blow it off when how much exposed is required is burnt. rub with sand paper or even with hand and removed the oxidised part of it. here u now have exposed wires exactly the length u wanted. the rest remains insulated with the coating