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30 The PCB Magazine • September 2015 You could say that today's automobile is a "computer on wheels," but from a point of ac- curacy it would be more like 35 computers on wheels. With printed circuit boards being the backbone of our electronic products, this is ma- jor market segment for our industry. The Evolution of Automotive Electronics Many of us can painfully remember our early cars that had manual door locks, win- dows we had to crank up and down, and doors that we actually had to put the key in the lock to open. The rise of electronic content in au- tomobiles has been relatively steep. The 1977 Oldsmobile Toronado had a very simple com- puter unit that was used for spark plug tim- ing, and the following year the Cadillac Seville offered an optional trip computer running a Motorola chip. This transformation is further supported when looking at cost; according to the publication IEEE Spectrum, as a percent- age of vehicle costs, electronics climbed to 15% in 2005 from 5% in the late 1970s—and would be approaching 25% today. Figure 1 highlights some major milestones in automo- tive electronics innovation. Today, even basic vehicles have at least 30 microprocessor-controlled devices, known as electronic control units (ECU), and a high- end luxury car like a BMW 7-series model can have up to 150 ECUs and five miles of wiring. These ECUs are the vehicle's electronic brains and control dozens of functions, including managing the efficiency of the car, the steer - ing and the surround view system to avoid collisions; the Wi-Fi system that provides in- formation on attractions, gas stations, traffic, etc.; and the electronic stability/traction con- trol to maintain proper steering, and sensors that deploy airbags during a collision. Then there are the audio/video center stack that provides entertainment and navigation, dash- boards with heads-up display (HUD), and, of course, electric windows with intelligence fea- tures. Software and multiple PCBs drive each of these ECUs that function both indepen- dently and as part of an overall vehicle elec- tronic network. by Steve Williams the right aPProach consulting (tra c ) the right approach Computer on Wheels FEAturE Column figure 1: automobile electronics milestones.