USB GPS Problem Solved
Okay, so a few months back I purchased one of these USB GPS to use with my laptop for road trips and wardriving. It seemed to simple enough, it’s a Prolific 2303 USB to serial adapter chip coupled to a NMEA GPS receiver, but I was having some weird issues where it would sporadically stop working when being used in my car. After doing some testing, I determined that it ran fine off the laptop’s battery, but cut out immediately if I plugged my laptop into my AC inverter. My guess is that the AC inverter wasn’t spitting out a very clean sine wave, and that the power fluctuation was being carried through my laptop’s AC adapter and through the USB port to mess up the GPS.
So, three possible solutions came to mind immediately. 1) Get a better AC inverter that spits out a cleaner AC sine. This would probably be expensive, and there’s only so much you can do with a car’s DC power supply anyway. 2) Get a better AC/DC adapter for my laptops. My thinking here was that something other than my laptops-for-less adapter might do a better job of scrubbing it’s DC output. 3) Some sort of USB power regulator (no idea if such a thing exists, or really how to build one.)
After doing some digging online, I found a couple boards talking about audio humming from PCs plugged into AC inverters, which presented a forth option: a DC-DC power adapter for my laptop. I did a little more digging and discovered that Targus makes such a device that works with my laptop, and it’s even sold at CompUSA.
So, before my Sunday D&D game, I stopped by CompUSA in Nashua and picked one up. Tried it out a little before game, and again on the way home from Denny’s. GPS worked the entire time, so I’d say this fixed it up nicely. Overall I’m rather happy with it, though the $80 price tag was a little much. I guess that’s what I get for buying a cheapy GPS in the first place. The Targus device is pretty cool though, and the DC-DC thing should be more efficient than the DC-AC-DC rig I had running before (and I don’t get interference on my FM radio anymore!) There’s some accessories you can get for it to charge all sorts of things, like my Clie or my cell phone, which I might consider down the road.
