[General Topics] joeavery2:
Support Page for the Big Bang Steering Wheel Interface

The purpose of this page is to provide support and answers to questions for the Big Bang Steering Wheel interface until our Wiki and support site at UnderGroundElectronics.net is finished.

We are discussing the Big Bang Steering Wheel interface project on Kickstarter.

A Quick Description: The Big Bang is a interface between the car and your tablet. Our goal is to enable you to install your tablet in your car with OEM like integration. We had to start somewhere and we are planning other items for the future but this critical first step we felt was the most nessasary thing for a every day user experiance.

We know that there are a lot of people and threads on installing tablets in cars. We've seen various methods to achieve this solution but no one has made a item for this specific purpose. Even if your car does not have steering wheel controls, this device allows for the waking and sleeping of the tablet while still allowing it to charge constantly.

This device is fairly simple in operation, however the automobiles they go in are not so simple. There are lot of things that can cause problems and we hope to address them here (until we can get our site up, and maybe even after since XDA is a go to place for trouble shooting problems with our tablets and phones).

Lets Start with a basic description of operation

Most autos that have steering wheel controls use a single wire behind the head unit. This wire is typically one of three types: Resistive Negative, Resistive Positive, and Digital. A few Autos use independent wires, one example is Harley Davison. Each button is independent and thus must use resisters to combine the buttons to a single wire.

Currently the Big Bang is made to work on Negative and positive resistive Autos. Data type is expected to be developed by the time we ship.

Finding the wire in your auto:

At the steering column is the best way. But BE WARNED, there is danger probing around with the electrical system of any car that has airbags. You should disconnect the battery and let the car sit at least 30 minutes before doing anything with the wiring in a car with air bags. (Yes we realize that this is very cautious stand but we don't want people getting hurt. If you are un-experienced with Automotive electrical or unsure of what you are doing you probably should consult you local Car Stereo Shop. At the very least use sites like "the 12volt .com" or ask for assistance here. AND NEVER EVER USE A TEST LIGHT, Voltmeters only here.

We can't stress this enough. The data systems and air bag systems in modern cars are very sensitive and can be damaged or set off with just static electricity. We can not be held responsible for what you are doing, we are simply trying to guide you. In my case I have years of car audio experience. I still run into things in new cars that I've never seen before and I've seen plenty of cars damaged by people cutting the wire that was the right color or "injecting voltage" to test something.

Moving forward:

Negative systems:

Typically a Negative system is one that the control wire will go negative from a resting position that is positive. In the case of most Honda's it rests at 5V and goes negative with each button. If you have a stock navigation system (In the case of the Honda. Others may be different) some buttons may be dedicated to the Nav Brain. That unit needs to be removed with the head unit to function properly and has special "reverse wiring" to provide all buttons functions.

Positive systems

Positive systems work just like negative systems but instead rest at or near ground (zero voltage). The voltage at the wire will go positive when a button is pressed.

Programming the Big Bang

Our site will cover most of this but at present the Big Bang is programmed via a PC. We do hope to one day be able to program it from the tablet, allowing one to tweak the controls after install and to improve installation experience. We will provide more detailed instructions closer to launch day but the short of it is you will download a program, modify it to fit your car/application then run it to program the Big Bang.

Connecting the Big Bang

We recommend using the Big Bang with a USB Hub that is powered. We have found some 12V to 5V dc to dc Converters we will link below as well as the USB hubs we recommend. The Big Bang will connect to the USB hub and the USB hub will plug into the tablet or phone. The big bang will have two wires that need to be connected. The Big Bang is powered from the USB power, so it and the tablet are always receiving power. It will have two wires to be connected. The white wire is the control wire and needs to be attached to the steering wheel control wire. The Red one is the ACC[essory] or IGN[ition] wire and needs to be tapped to it as a reference for the cars voltage. This wire should be fused as there is always a potential for shorting. It may be redundant but we still recommend fusing this wire independent of others, or using the same fuse used for the USB 12v to 5v converter.

Problems we've seen in our testing

First and worst problem I've experienced is cheap USB OTG cables. Some are very finicky about the position the sit in to make contact. It could be that they are old and worn out too. We plan to explain a "best methods" guide but best I can say is get decent quality USB OTG adapters for this use.

The second issue I've seen is random reboots. My n7 experiences these only when I'm using it in the car. I'm running Paranoid Android, and I don't believe it is the issue. I believe it is due to the faulty USB cable described above.

Other then that, we've experienced few issues but we are still in somewhat early testing phase.

I'll update this post with Q and A's as they come in. When asking questions about your installation it would be helpful for you to be as thorough as possible. Let us know if you are an experienced car audio person or not. Also make model and year of car may be important.

Until now this has been our idea for our car, we now open it to you. We can't promises anything but if you have suggestions, tell us. We may include the feature. We are working on other products as well to enable people to install their tablet and have it operate as normal as possible.

Tested Devices:

We've tested it on these devices so far but you can help. Get a USB OTG cable for your tablet, then plug in a USB keyboard or mouse and see if it functions. post your results and we'll add it to the list.

Confirmed working:

N10

N7

Galaxy Note2

Galaxy S3

Know to NOT work:

N4