Hacking your car stereo

Energy & Sustainability Technology
Hacking your car stereo

Unless you have a new car, you most likely don’t have an iPod input. You can usually just use a cassette adapter, but you can also open it up and just start messing around. If you want to crack it open, take a look at this web site first. It may save you some time and trouble.

Today I scored another point against that devious being, electricity, and without using a single bead of solder or hot-glue. Using only a screwdriver, a pair of pliers, a length of wire and an old headphone jack, I was able to rig my outdated car cassette tape player to play audio from an iPod or other mp3 player instead. Once again, I’ll provide detailed (albeit kind of poor-quality) pictures of the process and the idea behind it.

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13 thoughts on “Hacking your car stereo

  1. John Bognet says:

    I wanted to create an input for my ipod and other devices but not only was my car radio lacking an Ipod input it didn’t even have “RCA INPUTS” which a lot of head units have these days. I didn’t have a tape deck either so those adapters weren’t an option….

    I tried every type of FM transmitter i could find but even the fancy models left a lot to be desired.

    When i was using a wireless FM transmitter I had problems with static and feedback. Even when it was working properly the sound wasn’t exactly hi fidelity.

    Finally i found this solution which is not only cheap but will work on ANY and i repeat ANY car sound system or head unit… even the stock stereo as long as your vehicle is equipped with an FM radio!!!!

    How it works: This handy little adapter plugs into the back of your receiver where the wire that connects the exterior antenna to the interior reveiver would normally plug in–then the bypassed and now dangling Antenna wire plugs into the back of the adapter so that you dont lose your ability to tune in radio stations.

    The beauty of this adapter is that it is not only hardwired but it can be turned on and off from a remotely mounted switch!

    When you want to listen to your ipod or other device you turn the adapter on and it phases out EVERY FM station except for 87.9 which is the designated station.

    But unlike wireless fm transmitters there is absolutely no feedback or static and the sound quality is superb since its hardwired.

    The whole project costs as little as $40.00 and always less than $50.00

    I spent some extra money to make the project a little cleaner –here’s my itemized receipt

    39.99 – Scosche adapter

    note: this is all you need to complete this project but i added a few things which are itemized below to make the finished product have a cleaner and more “stock” look.

    2.99 Radio shack female to female adapter plug

    note: the scosche comes with a long length of stero wire capped with a male end plug similar to the end you see on a set of headphones…. it is designed to be plugged directly into an ipod or any other device’s standard headphone socket. I found this system somewhat sloppy ( i didnt like having a wire dangling from a hole in my dash when it wasn’t being used)

    To eliminate this problem I drilled a hole into a vacant spot of the dash that was slightly larger than the female to female adapter then hot glued the female-female adapter into place. The front of the adapter is left empty and the rear has the afformentioned male adapter permanantly plugged in and out of sight.

    Now when you look at the dash there is a small vacant stero headphone socket into which you can plug your ipod by using the next item on my list (see below)

    4.99 Radio Shack 6” stereo cable with male adapters on both ends.

    note: I keep this cable in my glove box so that when i want to listen to my ipod over the car speakers i simply plug one end of this cable into my ipod and the other end directly into the socket on my dash, when im not using the ipod it stowes away easily and leaves my dash looking neat and clean.

    If you want to get really fancy you can plug the male end of the modulator into a bluetooth receiver and have it all hidden behind your dash.

    Then keep the bluetooth transmitter in ur glovebox for wireles operation of the whole setup.

    2.99 Radio Shack Push button switch.

    note: The Scosche comes equipped with a black and white rocker switch but I didn’t like the looks of it so I swapped it out for a nifty red push button switch that matched my interior better.

    This was strictly aesthetic and you can find a variety of cool switches at any auto-parts store or at radioshack– some of you might even like to install a switch that lights up to remind you that your adapter is powered on but since its powered through the radio power you dont have to worry about forgetting to turn it off since in most cars it powers down when the key is taken from the ignition anyway.


    I’m considering typing this up as an instructable but i really dont have any pictures to go along with it so hopefully the text version helps, feel free to email me with questions johnbognet@gmail.com

  2. AKADriver says:

    This is a good easy project – it wouldn’t be too hard to route those loose wires through the partially-open cassette door and finish them with a 1/8″ female audio jack.

    Anyone doing this owes it to themselves to get the proper tools for removing the head unit from the car. They’re usually very cheap or even free – for my Mazda and many cars it only requires bent coat hanger wire.

    For most cassette players, the signal from the read head goes through a pre-amp to bring it up to line level before going into the logic that selects the audio source. Finding this point in the circuit would be the ideal place to attach an auxiliary input. Alternately, one of the other inputs could be repurposed (such as the signal coming from the AM tuner).

  3. Marc de Vinck says:


    Yes, make an instructable!!!

    All you need are a few pictures. (I know, that’s the problem) Thanks for the detailed information!

  4. Andrew says:

    I used a PIC instead of the dummy tape, to simulate the correct signals from the tape deck. I also bypassed the tape head preamp which improved the audio quality a bit.

  5. Mahto says:

    I also did something similar, but more as a form of camouflage- I was having too many fancy new radios stolen, and figured the old factory one would be less of a target!

    I attached my input directly into the main circuit board, and used a bypass transistor IC from an old stereo to switch between the onboard audio source (radio or tape), and the external input. A microcontroller watches the signal across a button on the front panel on the stereo, so the external input can be switched on just by holding down the button for a short time. Finally, I drilled some holes in the back casing of the system to add RCA jacks to the back, so a stereo cable can be plugged in.

    There isn’t a formal writeup, but I have a Flickr set to document the various steps:

  6. poojalooba_cow says:

    Thanks for linking to my blog, MAKE! It quintupled my total blog traffic throughout the course of a single day! It’s kind of mind-boggling to see something that I wrote distributed around the Internet like this…

    @AKADriver – the partially-open cassette door is partially open because the dummy tape is inside it. The dummy tape has to engage the reader-head to trick the machine into thinking it’s playing a tape, when it’s really playing my audio. So, routing the wires through there would interfere with the operation of the dummy tape.

    also @AKADriver – I hadn’t thought of finding the pre-amp source in the circuit. Well, I entertained the thought for a moment, but the goal of my project was first and foremost ease and convenience – also I currently don’t have a soldering iron, but in a few days once I do have one maybe I’ll try again and solder my wires into the right location for better sound fidelity.

    Anyway, thanks for the backlink and thanks for the feedback, everyone!

  7. Jesse Ransom says:

    omg guys!!!

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