Thursday, July 1, 2010

Motorola T-605

This is a little off-topic since it doesn't have to do with computers.  Last year I purchased a Motorola T-605 Bluetooth hands free system for my car.  In my younger days I experimented quite a bit with automotive electronics so I felt I had both the experience and the interest to install it myself.

Effort * Quality = Results
With any skill, lack of use makes the neurons that drive the skill reluctant to participate.  However, if you can find the right leader, the rest of them soon fall in line.  Initially, I too was reluctant to commit to this effort.  I was hesitant to put in the time to run dedicated wiring for power and ground.  I thought that it might be alright to simply tap into the power and ground sources for my head unit.  This method worked about as good as the effort put into it: not very much.  The problem was that the wiring used by the vehicle's manufacturer just barely covers the amount of power required without introducing anomalies.  In fact, if the T-605 drew enough power, it could exceed the wire's ability to maintain it's temperature while delivering the electrons downstream.  So, this minimal amount of effort mixed with low-quality wiring led to the introduction of noise in the signal delivered to my head unit.

Size Matters
Wire selection is critical.  There are many types of wires available, stranded, solid core, shielded, insulated, etc... In this case, the wire needed to supply 3 amps at 12 v reliably over a distance of six feet.  The distance is important because the further you need electricity to travel, the more resistance you will experience with a given wire.  Wire selection can become complicated easily, but for my purposes I simply needed to select the proper gauge of insulated wire. The 24 gauge wires in my vehicle were insufficient to supply the kind of power the T-605 required.  Since six feet of wire isn't very expensive, I chose to over-engineer the solution by using 16 gauge wire dedicated to the T-605.

Effort makes a difference

Now that I was committed to completing the project and doing it correctly, I broke out my soldering tools.  I made sure that all wire connections were soldered and insulated properly.  Where I wanted to join the 16 gauge wire to the 18 gauge wire that the T-605 came with, I used a "Western Union" splice and then sealed it with solder and heat shrink wrap.  I like this splice because it's designed to become tighter if you should ever accidentally pull on it.

I used a couple of soldered quick-disconnect connectors to make it easy to service the T-605 should I ever have to remove it.  I used a pair near the battery and another pair near the T-605.

Western Union Splice

The point of this article is to illustrate the relationship and importance between effort and quality.  If you work to maximize both, the project will take MUCH longer but you will be much less likely to re-visit the effort in the future.  I know this from my experience managing projects, but in my personal life, time is so limited that sometimes I neglect to remind myself of my professional experience.  In this case, I didn't come to this conclusion on my own.  I had a discussion with one of Motorola's excellent support engineers.  He was patient and led me to the conclusion that I had simply done a poor job without being condescending.  I really appreciated his help.  More than a year later, the T-605 remains in my vehicle and works great.  I've enjoyed streaming blogs, audio books and Pandora over my factory head unit.  My kids love listening to children's audio books as much as I do.  It's been a life-extender for my vehicle.  I recommend trying a project like this on your own if you should ever feel the inclination, just remember to consider Quality and Effort!

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