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Recycling an Android Phone As a Handheld GPS?
imblum writes "So my dad's antique handheld GPS unit just went toes up and I was considering replacing it for him with an old Android Smartphone. All he really needs it for is hunting and camping (no navigation), so I don't want to pay for cell or data service. I found the program Mobile Atlas Creator to download map files onto the SD card, and an app called Maverick Lite to view them. Now all I need is to decide on an Android phone. I was considering a Samsung Behold II ($100-200 on Craigslist), but thought it would be nice to get some input from the Slashdot community. It seems like I can get a lot more functionality for the money out of an old Android than I could from a big name handheld GPS. Does this plan sound reasonable? Is there anything I'm overlooking?"
There's a reason why 'real' GPS units cost more, despite not necessarily having as many fancy 'features' that often end up being unnecessary.
Cell phones rarely have WAAS. Cell phones usually also use the cellular system to receive the phase of the GPS satellite transmission to aid in reception--but--if you don't have any service, the accuracy can get pretty deplorable (well, compared to say my GPSmap 60CSx that usually locks within fourteen to sixteen feet)...the battery life isn't as good, cell phones are horribly made, and the chipsets and antennae are simply much, much, much better in a dedicated unit. Pick up a used GPS--that's a real GPS--and it will be much better suited to hunting and camping rather than looking for the closest Starbucks. Real GPS units have rubber gaskets for a reason.
An android phone will have a bigger, more colorful screen and a more open/versatile OS, and it will undoubtedly be easier to load whatever maps you want on it, rather than vendor-approved, possibly expensive ones. Without some sort of additional protection, though, the device will break the first time it gets dropped on a rock or rained on. It'd be more suited to city and car navigation than camping and hunting.
It might not be a good idea for multi-day hikes, but you can probably get reasonable single-day battery life out of many or most models. Particularly if you power off the other radios, and if you can power off the unit itself when it's not being actively used.
As to why this and not a dedicated GPS unit - sure, a dedicated unit will probably have better battery life, and it might be better for GPS usage in other ways as well. But it's almost certainly less flexible. I can really only use it for GPS - what if I also want to take pictures or make notes about each location I'm at? Sure, I could carry more dedicated devices to handle those functions. But at some point, isn't it worth carrying one device which can serve several functions while fitting in my pocket? Also, a dedicated device probably comes with the software package that it comes with. Adapting a smartphone means that you're running a mobile computing platform which just happens to have a GPS sensor - you can probably pick among several options for the software, or even program your own. Some smartphones also have additional sensors like accelerometers or compasses which could improve the functionality - not all, of course, but potentially valuable if you can get it. Maybe some dedicated GPS units have this as well, but I doubt that the really cheap ones do.
For the subby, the situation they describe really does make it sound like a dedicated unit is at least worth a serious look. A dedicated unit is more likely to "just work" and that's likely all the guy wants.
Android is what, 22 months old?
"So, what kind of rock should I get? Granite? Sandstone? And which quarry should I get it from? I was thinking that granite would last longer but sandstone would ride nicer and would be easier to lob at a dinosaur in case of attack."
Wheels made from rocks are quite a demanding application. Most rocks are very strong under compression (e.g., in a building or wall), but many are relatively weak under tension with low elastic strength, and therefore they will break relatively easily when a wheel is sheared laterally, such as when rounding a turn (due to forces acting perpendicular to the direction of travel). A way to mitigate this is to make the wheel rather thick, but the disadvantages (weight) are obvious.
Granite is probably a better choice than sandstone because most sandstones have individual grains that are in contact only over a small part of their area, with the spaces in between cemented together by other minerals that are often quite soft (e.g., calcite). Worse, many sandstones don't have those spaces fully infilled (i.e. the sandstones are porous), which does increase their elastic modulus, but makes the material more prone to surface wear (it's easier to rub the mineral grains off the surface -- and it's even worse if water freezes in your neighborhood). Cracks tend to propagate easily in sandstones. By contrast granite and other intrusive igneous rocks are comprised of mineral grains that grew together as the molten rock crystallized and therefore the grains interlock quite tightly with virtually no open spaces between them (i.e. they are holocrystalline and often equigranular). A downside, however, is that some of the more common minerals in many granites (e.g., feldspars and micas) have good mineral cleavage (it's not what you think, it's planes of weakness in the crystal structure), and the more coarse-grained granites therefore tend to break more easily (because the cracks propagate along the relatively large, weaker cleavage planes in the large grains). One way around this is to look for a granite with less of the minerals that have cleavage (i.e. less feldspar and mica) and more of the minerals that don't (e.g., quartz), and to choose a granite that is as fine-grained as possible (then the random orientation of the cleavage planes from grain to grain will mean the cracks can't propagate as far along them before bumping into a grain boundary). As a bonus, quartz has a greater hardness than feldspar or mica, so frictional wear will be reduced too. Therefore, a nice, fine-grained quartz-rich granite (ideally a quartzolite, but they are quite rare) is probably your best granite option. A fine-grained, non-vesicular mafic igneous rock, such as a basalt or diabase/dolerite, might work well too, although they have higher density and don't have significant quartz (but the very small grainsize partly offsets this).
But why limit yourself to granite or sandstone? You can get
As someone who owns an Android phone AND a dedicated GPS, perhaps I can inject something into this conversation:
Another consideration is how well it will hold up under the elements. Even the cheapest Garmin eTrex (which I own BTW) is pretty rugged. I wouldn't trust my Android smartphone out in the woods in the rain, mud, etc. Some other pluses of going the dedicated route:
- Battery life is better on the dedicated GPS, and when it does run down, it takes standard AA's.
- The dedicated GPS seems to have a better "time to first fix" than my Android phone, but that just might be because of the specific model. However, if your one purpose is to do GPS, it makes sense that you would do it better than a multipurpose device.
I do think it would be cool if there was a dedicated GPS that took pictures too. You could use the GPS to geotag the picture and have it as an icon for a waypoint to help remind you what that waypoint is.
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www.moneybythenumbers.com
I did a reasonably extensive amount of research into how to do this, and I'm pretty confident I know the answer.
1. Get OruxMaps - it allows you to use maps without an active internet connection.
2. While connected to wifi, download the tiles from google terrain (or one of the other map sources available). If you know exactly where you're hiking, you can get zoomed in maps for say a 20 mile square around the center of your hike with amazing resolution.
3. Put your phone in a plastic bag, and only take it out if you actually don't know where you are (I find that I almost always do).
In terms of battery life, I was using my android phone as a camera too, and checking GPS every few hours to verify I was in the right place, and it lasted for three days taking down the battery by 40%. Make sure to turn off the cell tower seeking and such or else you will drain the battery really fast. Airplane mode probably won't allow you to receive GPS, unfortunately, but you can at least turn off wireless, data connections, etc.
If you aren't going to be gone very long, and you want a cool log of your trip, you can have OruxMaps poll the GPS in "power saving" mode, which as far as I can determine seems to mean connecting, and then dropping to low power (non-receiving) mode for 10-20 seconds before polling the satellites again. Then you can tell it to make a "track", and it will record your hike -- average speed, immediate speed at each point, speed distribution, altitude map, total distance, and other cute information.
Hopefully someone will mod this up high enough that the submitter can see it... this is the part of ask slashdot that always confuses me. Hopefully a few hundred other people came up with the same solution, so at least one of us is actually noticed =)