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Archive for the 'Android OS' Category

Copy Map/Data Files To And From Your Android With Wireless File Transfer Lite

Application Name: Wireless File Transfer Lite

Description: Lets you copy data files to and from your Android unit using a wireless connection and browser interface.

Publisher’s website: Lextel

Cost: Free

Version/date reviewed: v. 0.4.2a  /  3-8-11

Phone/OS: Droid X / Android 2.2


Android Market (mobile app only)
Android Market (browser)

If you use your Android phone regularly as a map tool, or to record data, you’ll likely need to regularly transfer data to your Android (like map files), or from your Android (photos, waypoints, tracks, etc.). This can be a real pain. I’ve covered a few ways to do this in previous posts (one, two), but I’ve recently added a new solution to my phone that, despite some limitations, is usually more convenient: Wireless File Transfer Lite.


When you start up the program, the initial screen shows the web address you’ll need to enter to access the files; it will usually be your Android’s assigned IP address on your local network, plus a port number (8888 here). Confusingly, you need to tap the “Stop” button to start the service …


… and once it’s active, as above, you need to tap “Active” to turn it off.


Entering the web address into your browser brings up the WFT interface, defaulting to the main sdcard directory. Here, you can delete/rename directories (with caution!). Click on a directory folder name …


.. and see all the files and subdirectories within that directory folder, with delete/rename options as well. Here’s the directory with shapefiles used in yesterday’s review of the shapefile viewer SHP Viewer. To download a file from this directory to your computer, just click on it, and it will be download to your default download destination. Right-clicking, and choosing “Save link as” … will *not* work here, so there’s no easy way to specify an alternate download destination.


To upload a file from your computer to your Android, navigate to the destination directory on your Android, then click the “Upload” button at the bottom of the page to select the file on your computer you want to send to the Android. One huge drawback: only one file can be uploaded at a time. So if you have many files, it would probably be faster to use a different wireless solution, or connect your Android via a USB cable and put it in USB Mass Storage mode to access directories using the File Explorer. The “Install” button lets you select a “.apk” program file on your computer, and have it install on your phone; useful for those programs that aren’t available on the Android Market (but watch out for potentially hazardous apps that may install viruses, or compromise your phone’s security).

Other issues: Upload/download speed will be determined by your wireless network’s limitations. On a good 802.11g network, transfer speeds should be fast enough for most files. If the files are really large, unless you have a phone and network that supports the faster 802.11n standard, you’d probably be better off again connecting the phone via a USB cable.

There is a free “Pro” version of Wireless File Transfer that adds file and app management functionality, but I find other apps more useful for that, and it just complicates the interface. Another, similar app is File Expert, which on paper is superior – it offers file management, a web-based interface, a built-in FTP server, connections to network storage devices, and much more. But the interface is more challenging, and it had an annoying tendency to freeze up or force-close on a regular basis. Try it if you like, but Wireless File Transfer offers a simpler interface without complications.

Final thoughts: For large files, or large numbers of files, you’ll probably want to explore other options. But for simple upload/download of a few files from your Android phone, Wireless File Transfer Lite is fast, simple and easy. Highly recommended, especially at the “price”.

Why Use An External Bluetooth GPS Receiver With An Android Phone?

Google’s specification for an “official” Android unit, that allow it to use Google’s logo and have access to the Android Market, includes a requirement for a built-in GPS receiver. That’s why the new line of Archos Android tablets need their own app marketplace – they don’t come with GPS receivers. So if Android phones come with GPS, why bother with an external Bluetooth GPS receiver, especially when it will cost you extra? Here are a few good reasons:

1. External Bluetooth GPS sidesteps the Motorola “GPS In Airplane Mode” problem.

Posted about this yesterday; basically, some Motorola Android phones have a bug where GPS won’t work if you turn Airplane Mode on. Bluetooth GPS doesn’t have any problems – works perfectly in Airplane Mode.

2. External Bluetooth GPS offers a second position data source, letting you run multiple GPS apps simultaneously.

I’ve noticed that if you have one app getting position data from the GPS, and then start up another app that also looks for GPS data, they don’t always play well together – the second app can take over the GPS data stream completely. If one app supports Bluetooth GPS natively, then you can track position with that, and also run a second app that uses the unit’s internal GPS.

3. External Bluetooth GPS can give you slightly more accurate positions.

I have yet to find a single Android unit that has a GPS chipset that supports WAAS (Wide Area Augmentation Service). WAAS is a satellite signal that broadcasts real-time correction data for several sources of GPS position error, including satellite time/position errors and signal transmission errors in the ionosphere. Not terribly important while the sun is quiet, as it is now, but as the sun moves into a more active phase over the next few years, WAAS can improve the position accuracy by a few meters. Most external Bluetooth GPS receivers come with WAAS turned on as the default.

External GPS units can also come with larger antennas, and have room for bigger (and better) GPS chipsets, allowing for more accurate position determination. And because they’re not tied to your phone, you can place them in a location where they might get better satellite reception, e.g. the top of your backpack, the dashboard of your car, even under your hat. I hope to have a post in the near future comparing the accuracy of my Droid X’s built-in GPS unit, an external Bluetooth GPS receiver, and a high-quality handheld dedicated GPS unit (Garmin 60Cx).

4. Using an external Bluetooth GPS position instead of the built-in GPS can extend the battery life of your Android unit.

In a previous post, I looked at the battery drain from GPS, Bluetooth, WiFi, and cellular. The built-in GPS had the biggest power requirements by far; in comparison, turning Bluetooth on had virtually no effect on battery life. I just ran some additional comparison tests on battery life for the Droid X using internal GPS with Bluetooth off  vs. external Bluetooth GPS. The unit was in Airplane mode in both cases, to eliminate cellular/WiFi power drain. I used the TrekBuddy map app, which lets you choose between the internal GPS and an external Bluetooth GPS as the GPS position source. Approximate battery life is given in hours, based on the time to drop from 100% battery to 60% battery. For one set of tests, the display was turned off; for the second, the display was left on continuously at 50% brightness.

Display off Display on (50% brightness)
Bluetooth GPS 20.2 hrs 9.1 hrs
Internal GPS 11.0 hrs 5.7 hrs

Results are pretty dramatic – switching from the internal GPS to an external Bluetooth GPS cuts almost doubles battery life when the display is off. Even with the display on, the battery life with the external Bluetooth GPS is actually comparable to some stand-alone GPS units. For example, battery life for the Magellan Triton or deLorme PN-40 units with two AA batteries is often a bit less than 10 hours under normal use. If you remember to turn off the display when you don’t need it, you could easily get 15+ hours of continuous use by switching over to an external Bluetooth GPS.

5. An external Bluetooth GPS is cheaper than a spare battery.

External Bluetooth GPS units aren’t free, but they don’t have to be terribly expensive. Basic models like my Holux M-1000 (which works great with my Droid X), or the Globalsat BT-359 run less than $45, which is the cost of a standard OEM spare battery for my Droid X. My Holux will run for 16 hours on a charge, which is just about the same time you can run the Android phone before it needs recharging as well.

Some Android GPS apps like TrekBuddy already come with built-in native Bluetooth GPS support, which doesn’t require any additional apps or settings. Other apps, like Topo Maps, don’t have native Bluetooth support,  but there are “helper” service apps, free and paid,  that will let those apps use positions from an external Bluetooth GPS as well. I’ll be reviewing some of those in upcoming posts.

Fixing Some Common GPS Issues With Android Phones

I’ve run into a couple of minor GPS issues with my Droid X phone, and thought I’d post my solutions/quasi-solutions to them, in the hope you might find them useful some day.

Problem 1: GPS takes a very long time to get a fix, and only shows 1-2 satellite signals during that period.

I’ve had this pop up a few times, where it takes 15-60 minutes for a good solid position fix, even when Assisted-GPS is enabled. When this happens, signals from only 1-2 satellites are listed as acquired, even though many more satellites are in the sky. Powering off and on doesn’t solve the problem.

Solution: Clear out your Android unit’s cache partition.

1. Find out how to start your Android unit in “Recovery Mode”. Unfortunately, there’s no standard way that works with every phone, so you’ll have to Google your phone’s name and “recovery mode” to find out what works for you. On my Droid X, press the Home and Power keys simultaneously while turning the unit on, until an exclamation mark icon pops up, then press the Search button.

2. Select the “wipe cache partition” option. On my Droid X, I sse the Volume up/down keys to highlight “wipe cache partition”, and the camera shutter button to select that option.

3. It will take a few seconds, then you’ll get the message “Cache wipe complete”. You can now select the “reboot system now” option, and start up your phone normally.

No guarantees this will work, but in one case where I wasn’t able to get a GPS fix for two hours, even with multiple power cycles, going through this process immediately fixed the problem. It did seem to screw up my compass calibration once or twice, so you might check your compass calibration after doing this. Don’t know exactly why it works, but I suspect it deletes the old GPS ephemeris file, requiring the system to rebuild a new one.

Problem 2: Motorola units can’t get a GPS fix in Airplane Mode.

Got a comment recently from someone who reported that they couldn’t get a GPS fix when their Motorola Droid X was in “Airplane Mode”. Turning Airplane Mode on shuts off WiFi and cellular, conserving power; given how much battery power the GPS sucks up, this should help extend battery life a bit if you don’t need a phone or data connection. I’d used Airplane Mode sometimes, and not seen that  problem; but after further investigation, I found that my phone also has issues as well.

  • If you start GPS tracking with Airplane Mode off, then turn Airplane Mode on, GPS tracking will work correctly.
  • If you turn Airplane Mode on, and start GPS tracking within a short period of time of doing that (< 5 minutes or so), GPS tracking will work.
  • If you turn Airplane Mode on, and try to start GPS tracking after 5 or more minutes have elapsed, you will be unsuccessful. I didn’t see the problem because I always started GPS tracking right after turning Airplane Mode on.

This is a fairly-well known problem with the Verizon Droid units manufactured by Motorola (Droid, Droid 2 and Droid X); Droid units made by HTC (Eris, Incredible) do not appear to have this problem. One site suggested the problem lies with the Assisted-GPS function, but I don’t think this is correct; if I turn off Assisted-GPS on my Droid X, it has no effect on this issue. Running a test app, I can see that the GPS chipset is outputting NMEA data in Airplane Mode, but no coordinate position info is coming out. Sometimes, a GPS satellite signal will pop up for a second or two, then disappear and not come back.

I haven’t yet found a full “solution” that resolves this issue, but there are some “quasi-solutions”:

  • Leave Airplane Mode off. I’ve been able to get a solid GPS fix in this case even when there’s no cellular connection (e.g. in the bottom of a very deep canyon). The disadvantage is obviously decreased battery life. You can turn WiFi off independently for a bit of extra power savings, without affecting GPS signal acquisition.
  • Turn Airplane Mode On, then immediately run the app that requires a GPS fix and keep it running. Disadvantages are obvious: substantial battery drain, and you may not be able to run another program at the same time.
  • Complain to Motorola, and hope they fix the problem. Here’s a link to their support page; choose your model, then send them an email asking (nicely) to fix this problem.
  • Final solution costs a few bucks, but sidesteps the problem completely, works with any app that uses GPS, improves accuracy, and reduces battery drain dramatically. And these advantages apply to any Android phone, including those that don’t have the Airplane Mode problem. The magic solution is to use an external Bluetooth GPS receiver with your Android phone. Tomorrow, I’ll post about the whys and hows of this solution, and the rest of the posts this week will be about apps (free and paid) that let you use an external Bluetooth GPS receiver with any app, even those that don’t have native Bluetooth support.

Transferring Geographic Data Files To And From An Android Unit II

Second part of a series (part one here) on how to copy map files and other geographic data to and from your Android phone.

3. Awesome Drop

A somewhat unusual approach, but seems to work quite well. Install the Awesome Drop application on your Android unit:

Continue reading ‘Transferring Geographic Data Files To And From An Android Unit II’

Transferring Geographic Data Files To And From An Android Unit I

The past four posts (one, two, three, four) have covered desktop applications that create offline map files for use with some Android map display and GPS tracking apps. But once you’ve created the maps, you need to get them onto your Android unit to use them. For that matter, if you use an Android app to save geographic information like waypoints and tracks, you’ll probably need an easy way to copy those files back onto your PC, or share them with others. It should be a simple process, but often isn’t. In my Droid X manual, there’s only a very short section on this, and it’s both limited and wrong. This post and the next will cover several different ways to move file onto, and off of, an Android unit, listed here roughly in order of speed:

  • Direct USB connection (fastest, but not always convenient)
  • FTP server (second fastest, but least convenient)
  • Online file transfer service (convenient, but only copies files to Android, not from)
  • Online file storage/synchronization services (slowest but most flexible)

Each has advantages and disadvantages, but one or more of them should meet most file transfer requirements. I’ll cover the first two today, and the others tomorrow.

1. Direct USB Connection

Your Android unit should have come with a cable that lets you hook it up directly to your computer. However, the default connection only allows for transferring media files from your computer to your Android. To copy data to/from your Android’s microSD memory card storage, you’ll need to put it into USB Mass Storage Mode:


Figure 1: Connect your Android unit to your phone with the USB cable; you should get a message indicating that it’s connected, and the USB symbol should show up in the status bar.


Figure 2: Drag down the status bar to view the message; you’ll see one that says USB connection. Tap on that …


Figure 3: … and the USB mode menu will appear. Select “USB Mass Storage” and tap OK; your computer will now mount the Android’s microSD card as a USB drive


Figure 4: Here, the Android microSD card is listed as removable disk G:. You can now navigate the folder structure through your computer’s file explorer


Figure 5: … and copy data to/from the unit. For example, I could copy the maps created in recent posts into a subfolder of the TrekBuddy folder, and could copy waypoint/track files from that folder, or from the TurboGPS folder


Figure 6: IMPORTANT! Once you’ve completed all file operations, don’t just disconnect the cable directly; you may wind up corrupting the memory card, which would be bad. Eject the microSD card disk by right-clicking on it and choosing eject, or using the “Safely Remove Hardware” option in the traybar icon. Once that’s done, go to the USB mode menu (from step 3), select PC Mode and OK, then wait a few seconds for the Android unit to re-mount the SD card.

Since this approach uses a USB 2.0 connection running at 480 Mbps, it’s going to be the fastest at copying data, and is probably the best choice for large files. But unlike the remaining three options, it requires that you have the correct USB cable handy. You could also pull the microSD card out of your Android unit, put it into a card reader, and then copy/move files from there; if you do this, make sure you follow the same “Eject / Safely Remove Hardware” process as above. But many Android units require you to remove the battery to access the microSD card, which can make that approach inconvenient.

2. Android FTP Server

Convenient, since it doesn’t require a cable, and fairly fast since it copies/moves files at the top speed of your wireless connection; you also don’t have to worry about dismounting/mounting your SD card. But highly geeky, since you have to install a FTP server program on your Android, configure it, then set up a network folder on your main computer that links to the FTP server. I’ve set it up myself, and it works, but I find the direct USB connection more convenient, faster and easier to use. Full directions available at the Android Police website.

Last two approaches tomorrow.