Champagne Electronics on a Beer Budget
With a bit of ingenuity, research, and know-how, a cruising couple builds a state-of-the-art package for less than $2,000. "Electronics" from our March 2012 issue.
Choosing the PC
Aboard Lyra, we like our computers, and we appreciate having the ability to upgrade, update, and multitask that comes with an onboard PC. Our nav-station PC would pull double duty as a second computer for general use. The challenge here was to keep power consumption and size to a minimum. Laptops are very good at conserving power, but we wanted a permanently mounted screen and a clear desk for log entries and chart work. Fortunately, several companies in recent years have integrated laptop technologies into desktop-PC formats. The Asus Eee Box B202 PC measures just 8.5 by 1 by 7 inches and can be mounted in a variety of orientations. It uses the same hardware as the Asus Eee Laptops, which makes it both small› and very power efficient; its 110-volt power pack can be snipped on the 12-volt output side and hardwired to the ship’s power.
Wiring everything together (above) was the project’s most challenging task.
PCMall.com was very helpful in assisting me to build an Asus Eee Box B202 PC with a 500-gigabyte Seagate hard drive and 2 gigabytes of DDR2 RAM. The processor is a dual-core Intel N270, which sips power at only 36 watts when wide open and provides adequate performance. The built-in WiFi even has an external-antenna connection that we’ll eventually connect to an omni-directional antenna on the mast. There’s no CD/DVD drive, so everything needs to be loaded via an external drive on one of the four USB ports or the SD card reader. To initially load the operating system or copy any files, such as charts, that are too large to email or download, we find that a 8-gigabyte SD card works well.
Sourcing the monitor was one of the project’s more difficult tasks. We wanted as large a screen as possible that would fit in our available space, which measured 15 inches from corner to corner, and it needed to run on 12 volts. The smallest screen that I could find new in stores had a diagonal measurement of 19 inches, and it ran only on 110 volts. Yes, there are many automobile monitors on the market, but they’re costly. We ultimately learned that many of the LCD flat-screen monitors built in the early 2000s had a 110-volt power supply with a 12-volt output that could be wired directly to the ship’s power by removing the 110-volt power pack. On Craigslist, we found a used 15-inch HP monitor for a whopping $40.
The last piece of the basic setup was integration. Getting the GPS, the depth sounder, and the other new instruments to talk to the PC and to each other was extremely time-consuming. Once each wire was cut to length, it needed to have a terminal end crimped on and soldered, and then have heat-shrink tubing applied. We also tested multiple configurations and communication each step of the way. If we had instruments that “spoke” NMEA 2000, this would’ve been much simpler to do.
And because we want to add more instruments to the mix later, we bought a StarTech ICUSB2324X Four-Port Professional USB-to-Serial Adapter Hub with COM Retention. This hub takes up to four separate DB9 connectors (9-pin serial connectors) transmitting either RS232 or NMEA data and condenses that data to one USB port on the computer, which frees up USB ports on the PC and resolves potential data conflicts. Jen and I eventually want to install an autopilot and wind instruments; each will connect into one of the DB9 ports on the StarTech for interfacing with the ASUS PC. If all we cared about was the GPS/computer interface, we could’ve purchased a simple serial-to-USB unit for less money.