Tricking An Ancient Protocol To Play Tunes

November 6, 2015 by Bryan Cockfield 32 Comments

A lot of technological milestones were reached in 2007. The first iPhone, for example, was released that January, and New Horizons passed Jupiter later on that year. But even with all of these amazing achievements, Volvo still wasn’t putting auxiliary inputs on the stereo systems in their cars. They did have antiquated ports in their head units though, and [Kalle] went about engineering this connector to accommodate an auxiliary input.

The connector in question is an 8-pin DIN in the back, which in the days of yore (almost eight years ago) would have been used for a CD changer. Since CDs are old news now, [Kalle] made use of this feature for the hack. The first hurdle was that the CD changer isn’t selectable from the menu unless the head unit confirms that there’s something there. [Kalle] used an Arduino Nano to fool the head unit by simulating the protocol that the CD changer would have used. From there, the left and right audio pins on the same connector were used to connect the auxiliary cable.

If you have a nearly-antique Volvo like [Kalle] that doesn’t have an aux input and you want to try something like this, the source code for the Arduino is available on the project page. Of course, if you don’t have a Volvo, there are many other ways to go about hacking an auxiliary input into various other devices, like an 80s boombox or the ribbon cable on a regular CD player. Things don’t always go smoothly, though, so there are a few nonstandard options as well.

Un-crapifying A Car Stereo

January 2, 2014 by James Hobson 49 Comments

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[Noah Farrington] has just accomplished a major milestone in his life, purchasing his first car! A glorious 2001 Ford Focus wagon. While it may be a fully loaded luxury vehicle, it is missing one thing poor [Noah] can’t live without. An aux-in port.

He had a few options for rectifying the situation. Live with it as is, hack the strange Ford media protocol out of the back, or fool the CD player into playing his input. Naturally he chose the third option.

His first challenge was removing the deck from the car. People told him he’d have to buy fancy stereo removal tools — he made do with tent pegs and coat hangers. Using the same method as described in a past aux-in hack, he identified the audio in leads on the CD player’s ribbon cable. By carefully soldering in his own aux-in plug, he’s almost ready for business! Unfortunately, the CD player also needs to think that it is on for it to properly output the audio. [Noah] chose the simple solution — record a silent CD to always leave in the deck.

Stick around after the break to see it in action.

Continue reading “Un-crapifying A Car Stereo” →

Aux-in On A 30 Year Old Boombox

September 17, 2013 by James Hobson 26 Comments

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[Michael] just sent us this nice example of some good ol’ fashioned radio hacking.

He originally received the radio from his grandmother, and while he doesn’t listen to the radio much, he felt he couldn’t just let it go to waste. So like any good hacker he cracked open the case and took a look inside.

The beauty with radios from the 80’s is the simplicity of it all. They typically have single layer PCBs and nice big components which makes it so much easier to tinker with.

He used a bench power supply to bypass the main transformer for safety’s sake, and began probing the various points. The cassettes audio output was the easiest to find, but unfortunately it required the play button to be activated. Not wanting to lose functionality (or have an annoying rattling cassette mechanism), he continued probing and eventually found similar wires coming from the radio part of the PCB. Upon further probing he discovered he could trick the radio band button so that the radio would be off, but the output could still be used. After that it was just a matter of wiring, soldering, and adding an auxiliary plug to the case.

We’ve covered lots of auxiliary port hacks in the past, but this one is a great example of saving old technology from the dump.

[Thanks Michael!]

Car Stereo AUX Input Taps Into CD Ribbon Cable

June 28, 2013 by Mike Szczys 50 Comments

[Gezepi] wanted to add an auxiliary input to the stereo in his 1994 Camry. At first look there wasn’t an easy way to patch into the system. But a bit of probing with an oscilloscope and figured out that he could inject audio through the CD ribbon cable shown above. The CD reader is a self-contained unit that receives commands through the cable, and passes analog stereo audio back to the receiver portion of the head unit. We’re not sure how he figured out which pins to tap into, but it may have been as easy as probing with some headphones while a CD is playing.

The extent of his hack is documented in the image below. He cut the two audio leads on the CD side of the ribbon cable, then soldered his auxiliary jack on the receiver side of the cable connector. This ensures that two audio signals aren’t being piped into the receiver at the same time. Unfortunately it also means that he won’t be able to use the CD player. We have seen other methods that use a special audio jack as a pass-through which cuts the connection when a jack is inserted. That’s the method used in this Subaru hack.

Continue reading “Car Stereo AUX Input Taps Into CD Ribbon Cable” →

Hacked Auxiliary Port For A Car Stereo

February 19, 2013 by Mike Szczys 29 Comments

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We’re not sure if [Apachem25] is just lucky, or if installing Auxiliary ports on most car stereos is this easy. The dealership wanted $95 to put one in, but he managed to add a 3.5mm audio-in port to his car stereo for just a couple of bucks.

The connector on the back of his head unit is a 2×4 set of pins recessed in a protective plastic ring. It turns out that the audio connector cable for a PC CD-ROM drive has a 1×4 socket that is perfect for this. [Apachem25] simply clipped one of those cables in half and used both ends to interface with the Aux port. He found the pin-out for his particular model on the Internet. He needed a specific resistance value between two of the pins to get the deck to let him use the input. All that he needed was a quick bit of soldering. The left, right, and ground are brought around the side and soldered to an audio jack he added in the face plate of the unit.

If you’re still rockin’ the cassette deck our favorite automotive Bluetooth solution is still this one for a classic Beetle.

[via Reddit]

The Folly Of Adding An Auxiliary Audio Input To A Hyundai Sonata

November 4, 2011 by Mike Szczys 48 Comments

Why auxiliary audio inputs haven’t been standard on automotive head units for decades is beyond us. But you can bet that if you’re looking at a low-priced sedan you’ll need to buy an entire upgrade package just to get an audio jack on the dash. [Jon W’s] Hyundai Sonata didn’t have that bells-and-whistles upgrade so he decided to pop his stereo out and add his own aux port.

A big portion of this hack is just getting the head unit out of the dash. This is made difficult on purpose as an anti-theft feature, but [Jon’s] judicious use of a butter knife seemed to do the trick. He lost some small bits along the way which were recovered with a Shish Kebab skewer with double-stick tape on the end.

With the head unit out, he opened the case and plied his professional Electrical Engineering skills to adding the input. Well, he meant to, but it turns out there’s no magic bullet here. The setup inside the unit offered no easy way to solder up an input that would work. Having done all of the disassembly he wasn’t going to let it go to waste. [Jon] grabbed a nice FM transmitter setup. He wired it up inside the dash and mounted the interface parts in the glove box as seen here.

It’s nice to know we’re not the only ones who sometimes fail at achieving our seemingly simple hacking goals. At least [Jon] was able to rally and end up with the functionality he was looking for.