Arduino Translates Signals Between Steering Wheel Buttons And Aftermarket Head Unit

September 28, 2014 by Rich Bremer 19 Comments

There is no question that steering wheel mounted controls are super convenient. Reaching all the way over to the dashboard to change a radio station is so 1990’s. An ever-increasing percentage of new cars are coming equipped with steering wheel controls for the stereo, however, you’ll lose the button control if you change out the stock head unit to something a little higher in quality. Sure, there may be an adapter readily available for your car/stereo combination, but there also may not be. [Ronnied] took the DIY road and made his own adapter.

The first obstacle for [Ronnied] was to figure out the wiring on the steering wheel controls. After some poking around he found that there were only two wires used for all of the control buttons, each button only changing the resistance between the two wires. The button states could easily be read by using an Arduino’s analog input. A Pro Mini model was chosen for its small size as it could be housed in the radio compartment of the dash.

The next step was getting the Arduino to control the aftermarket head unit. [Ronnied] did some research regarding JVC’s Stalk digital control interface but came to the conclusion that it would be easier to direct wiring the Arduino outputs to the appropriate spot on the head unit’s circuit board. To do this the button for each function that would also be represented on the steering wheel was traced out to find a common point on the circuit board. Jumper wires soldered to the circuit board simply allow the Arduino to emulate button pushes. To ensure that the head unit buttons still work in conjunction with the steering wheel buttons, the Arduino would have to keep the pins as inputs until a steering wheel button was pushed, the pin changed to an output, the signal sent and the pin changed back to an input. This feature was easily created in the Arduino sketch.

Video below.

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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.

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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.

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Car Stereo Hack Gives Your Party Tunes And An Extra Place To Sit

March 29, 2013 by Mike Szczys 21 Comments

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With summer on the horizon it’s time to start thinking about outdoor leisure. [x2Jiggy] is chomping at the bit having recently completed this project. It’s a portable stereo that also gives you somewhere to sit.

Unlike several of these types of project, he didn’t build the system inside of a cooler. Instead, the chassis was built from scratch using MDF. This material is strong and easy to work with, but we’d bet the finished case is a beast to haul around because of the weight. At least there’s a heavy-duty handle on either side so that you and a buddy can split the burden. One nice perk is that it’ll make a sturdy yet comfortable seat thanks the padded and upholstered top.

The audio components that went into it are all automotive parts and shouldn’t mind being jostled during transport. A computer PSU provides the 12V needed by the stereo. But there are a couple of external rail connections if you want to haul around a 12V battery instead.

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]

Control Everything In Your Car With The Car Kracker

July 31, 2012 by Brian Benchoff 47 Comments

If your whip is a Honda, Toyota, BMW, Chrysler, VW, or Mini made in the last decade or so, the Car Kracker is for you. This project allows you to connect directly to your car’s computer system, allowing you to display messages on your stereo, play music off an SD card, and even override factory settings like always-on daytime running lights.

The Car Kracker uses ISO 9141, an in-car communications protocol that is now mostly used in foreign (for the US) cars. The build uses a Gadget Gangster Propeller board to connect to the CD changer port and OBD-2 port in the trunk, and the diagnostic port located under the hood.

With the Car Kracker, it’s easy to connect the Aux In on your stereo to an SD card loaded with music, or even plug in an iPod for the poor souls without a 1/8″ jack. Dealer customizations such as turning the ‘door is ajar’ noise off, toggling daytime running lights, and throwing a nav warning up are also possible.

Check out the two videos after the break, and if anyone has any more info on getting this deep into a car’s computer system (a wiki, maybe?), send a link in on the tip line.

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2005 Subaru Aux-in Hacking

June 27, 2011 by Mike Nathan 32 Comments

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The CD player in [mukmuk’s] 2005 Subaru Outback gave up the ghost, and faced with a long road trip ahead of him, he was desperate to find a way to listen to something other than static-filled radio. He considered a 3rd party auxiliary input solution, but after seeing a similar aux-in hack here, he figured he could give it a go himself.

The stereo head unit design was changed between the 2004 and 2005 model years, so while he had a good idea of what to look for, he had to find the proper components on his own. Once he identified the radio module, he was able to locate the left an right input pins through trial and error. He carefully soldered a 3.5” audio jack to the head unit’s input lines, wiring it to cut off the audio signal from the radio whenever his Zune was plugged in.

Everything was reassembled, and the input jack was inconspicuously mounted in a cubby hole just above the stereo. [mukmuk] is quite happy with his modification, and we’re guessing his road trip was far more pleasurable as a result of his work.