Inexpensive GPS Cycling Computer Alternative



maydog

Well-Known Member
Feb 5, 2010
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I picked up a few cheap, <$20, prepaid 3g android smartphones at Target to play with. Its a LG optimus dynamic. I don't plan on purchasing cell service so I keep them in airplane mode to save battery. The phone was crippled with a tiny ROM space, but I was easily able to root the devices, repartition the memory and load a custom ROM

One I gave to my kid to play games and music. The other, I loaded with Strava, Google MyTracks, Endomondo, a couple of free open source map navigation software. I use it to record rides for strava, turn it on and put it in baggie in my back jersey pocket. Ride data is transmitted automatically when I am in my Wifi range.

The thing works great, the battery lasts a couple of days on a charge. I bet I could fashion a decent mount for my handlebars.

This week, even better phones are on sale. One is less than <$20 (Kyocera event) and a waterproof dualcore model is just $30 (Kyocera hydro). These models should not even require any hacking to be useful. For that kind of cash, you cannot even get a decent wireless cyclecomputer.

The deals are not online, look in the store on the bottom of the phone racks.
 
...and you get a handy camera with your new cycling 'computer'! I've had good luck with both Kyocera and LG phones. Great idea, Maydog. It never occurred to me to use a cell phone for a bike GPS unit. Have you compared resolution and accuracy to a Garmin or other dedicated bike GPS unit yet? I know my Garmin is tracking about a dozen GPS and Glonass satellites at any given time and has an 'accuracy' of 31' (is that 31' total? 31' per thousand feet? 31' altitude accuracy? 31' linear accuracy? I no clue and neither does the owner's manual.).
 
It is at least as accurate as my Timex Ironman Globaltrainer maybe a bit better. The GPS watch records on a fixed 2 second interval, the Strava app on the phone is a 1 second interval. That is not a big deal on regular road riding, but does count on contested segments.

I have been doing a bit of track riding and there is a huge difference between a 1 second and 2 second interval there.

The icing on the cake will be to get ANT+ working. I have a few USB OTG cables and ANT sticks at home so I will give it a try. I know that Endomondo supports ANT sticks, STRAVA does not, but you can export from Endomodo.
 
OK no go on ant+ on the LG optimus Dynamic (lg38c), ant usb service requires android 3.1 and up. I guess I will have to pick up a Kyocera event and try that.

Of course there is the Selfloops device too.
http://www.selfloops.com/resources/tech-guides.html
 
Quote by Maydog: "The icing on the cake will be to get ANT+ working. I have a few USB OTG cables and ANT sticks at home so I will give it a try. I know that Endomondo supports ANT sticks, STRAVA does not, but you can export from Endomodo." Damn...and here I am...only able to understand Engrish! Between your first post and this one I have learned that some GPS enabled smart phones...even the cheapies...can be made to double as a bike computer. But I can't hack, jailbreak, code, jiggle firmware, reinstall operating systems, partition an EEPROM or get ANT+ up and running. Matter of fact, I've never even downloaded an app for any of my phones. I need to talk to my nephew... Off to figure out WTH an ANT Stick is. Man...I remember being so happy and content with my Strada Wireless.
 
I take it the GPS works even if the phone isn't activated for cellular service? So it's essentially "free GPS"?
 
Geesh, Campy, what's not to understand? :) ANT+ (sometimes ANT + or ANT Plus) is an interoperability function that can be added to the base ANT protocol (a proprietary open access multicast wireless sensor network technology).[1] It encourages interoperability and open-access to data between manufacturers of "smartphones, bike computers, diagnostics, power meters, heart rate monitors, remote control systems, etc."[1] and is promoted by the ANT+ Alliance.[2]
 
Originally Posted by CAMPYBOB

But I can't hack, jailbreak, code, jiggle firmware, reinstall operating systems, partition an EEPROM or get ANT+ up and running. Matter of fact, I've never even downloaded an app for any of my phones. I need to talk to my nephew...

It's very easy to "Root" and change the "Rom" (unlock the phone and change it's operating system). There are detailed non-nerd instructions online for "Rooting" and "Rom changing". (Just stay clear from the "XDI Developers forum", Newbie!
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I rooted a HTC explorer because I wanted to install more apps. The stock Rom only allowed a 200mb of space for applications and now the only limitation is the SD card. Battery goes longer too since there is not any of the google bloat-spy-ware running on the background to inform me about all the cafes around me with ratings.

I don't know about these phone brands but for the HTC you needed a code from HTC to unlock the phone. That was automatically generated by the website and sent with an email.

But: Now the "Bootloader" (the kinda BIOS screen of the phone) screen says "UNLOCKED" with fluo-green letters, complete with a picture of the android green robots skateboarding.
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At some point I wanted a warranty repair for the headphones. They said that because the phone was modified the warranty was voided. What does the software of it have to do with the headphones contact, I have no idea.

Maybe not much of an issue with a 20euro phone, but some GSM-nuts are getting some 500+ euro samsungs for which a free repair might be good.


Quote: Originally Posted by MotownBikeBoy .

I take it the GPS works even if the phone isn't activated for cellular service? So it's essentially "free GPS"?


GPS does work without the phone being connected on a service provider. What doesn't work is A-GPS (Assisted GPS). A-GPS is making a small data-call in order to collect some information about the current location and lock a GPS signal faster. (Data call that is of course charged according to "your plan" etc...)

Kinda useless but connecting via GPS the first time on a phone might take long before the phone finds any satellites. After that they usually connect fast.
 
Quote by MBB:
"Geesh, Campy, what's not to understand? :)"

Uh...pretty much all the stuff you said below!


"ANT+ (sometimes ANT + or ANT Plus) is an interoperability function that can be added to the base ANT protocol (a proprietary open access multicast wireless sensor network technology).[1] It encourages interoperability and open-access to data between manufacturers of "smartphones, bike computers, diagnostics, power meters, heart rate monitors, remote control systems, etc."[1] and is promoted by the ANT+ Alliance.[2]"


Ants is something that invade your picnic. Ant Plus is when they bring their friends, the grasshoppers.

My Garmin 510 and Cateye Stealth 50 are Ant+, but I had no clue you could get a cheap cell phone to work both GPS and receive Ant+ sensors without activating the phone! Learn something new every day!

Yeah, the guys on the firearm forums post about jail breaking their phones and stuff, but ain't nobody got time fo' dat!
 
After some experimenting, I found that neither the cheap LG or Kyocera will work with ANT+ as-is.

The good news is that the $20 kyocera comes with a $15 "entertainment" gift card. So I got a subway lunch or two along with the phone.
 
I used to a be a DOS 6.22 GOD! A GOD, I tell you! I could build awesome 'puters and configure with the best of them. Now...I can't even txt because the buttons are too small...
 
Originally Posted by CAMPYBOB

I used to a be a DOS 6.22 GOD! A GOD, I tell you! I could build awesome 'puters and configure with the best of them.

Now...I can't even txt because the buttons are too small...

DOS huh?
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C'mon noobie!
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