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Andronicus

Using a smart phone as a back country GPS How To

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There is a perception that smart phones are no good for use as a back country GPS. Here is how I have successfully employed my HTC Touch (Vogue).

 

First off, you must get a skin for it. You can get some decent silicone skins on e-bay for most phones for cheep. You should also install a lanyard; your phone is not as rugged as a hand held GPSr, so this will try to insure that it doesn't hit the ground. Most phones have a lanyard connection spot, so it should be super easy.

 

The big issue most people have is battery life. I employ a 3 pronged attack.

 

1) Turn of the phones radio! Not only is this a drain on your battery under normal conditions, but when you are out in the back country, your poor phone will transmit at max power (1/4 watt) trying desperately to find a cell tower. This will drain your battery quite quickly.

 

2) Spare batteries! If your phone is not an iPhone, pick up some spare batteries off eBay for cheep (<$10). iPhone users, your battery is not removable, so tough luck on this one. Second, build yourself a battery powered recharger. Most phones need a 5V charger. If your's needs 5V, use a 4 AA battery holder (off eBay for about $3). Cut a charging cable (if your phone uses miniUSB, just cut any old miniUSB cable), and connect that to the battery pack. You can use 4 regular AA batteries, but that puts the voltage at 6V (1.5Vx4). Most phones will not mind this, but some may. I use the new Energizer Lithium Ion batteries. This produces 4.8V (1.2Vx4), which will work great, and they have 2500mAh (each, but since they are in series, the energy don't add). That is likely 2x your energy your phone batterie has.

 

NOTE: Using 4 standard batteries, producing 6V may fry your phone! Most phones will be OK, but there is no guarantee!

 

3) Find an app that will turn off your screen, but leave the phone running (to keep the GPS active). For Windows Mobile, I use SVM Power Manager. I have it mapped to the camera button for easy access. I would imagine that most phone varieties have a similar program. When you use this approach, turn off the power saving mode that will put the phone to sleep. If the phone goes to sleep, your GPS will turn off.

 

The final piece to the puzzle is software. For tracking my hiking, skiing etc, I love GPSed. It is available for the 4 main smart phone Operating Systems, and is free (but is currently $0.99 for iPhone). If you want maps, you may need to do some googling. On my Windows Mobile phone, I use OziExplorer.

Edited by Andronicus

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Most phones need a 5V charger, so use a 4 AA battery holder (off eBay for about $3). Cut a charging cable (if your phone uses miniUSB, just cut any old miniUSB cable), and connect that to the battery pack. You can use 4 regular AA batteries, but that puts the voltage at (1.5Vx4) 6V. Most phones will not mind this, but some may. I use the new Energizer Lithium Ion batteries. This produces (1.2Vx4) 4.8V, which will work great, and they have 2500mAh (each, but since they are in series, they don't add), likely 2x your phone batteries energy.

 

Just to clarify this - I've also succesfully used 4 AA batteries to charge 5V items which would usually be charged from the USB port on a computer. WARNING: Although, as mentioned, some phones may not mind a 6V input, there is the chance you could fry the circuitry - the input is designed at 5V, not 6V. The trick is to use RECHARGEABLE batteries, as these are 1.2V each, instead of 1.5V for regular batteries (this is alluded to above, but not explicitely stated and I don't want people frying their expensive phones!).

To conclude:

4 AA non-rechargeable batteries = 1.5V x 4 = 6V = possible burnt useless gadget.

4 AA rechargeable batteries = 1.2V x 4 = 4.8V = happy gadget AND environmentally friendly (in terms of battery waste, anyway!)

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. iPhone users, your battery is not removable, so tough luck on this one.

 

Although iPhones are covered elsewhere I use an external battery, like the Juice Pack Air. The gaiagps app will use offline maps more conveniently than the Groundspeak app and import gpx files. That and geosphere and I am good to go, although I have only used it in the backcountry when I ran into problems with my regular gps.

 

As wonder whether I could use your trick and cut an iPhone charging USB cable into a battery pack. I am not sure of the voltage and have no need to try it. But I have seen devices that use batteries for this purpose.

Edited by Erickson

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As wonder whether I could use your trick and cut an iPhone charging USB cable into a battery pack. I am not sure of the voltage and have no need to try it. But I have seen devices that use batteries for this purpose.

 

I'm sure you can: go to www.instructables.com and have a poke around: I'm sure they've done it!! (Warning: this website will seriously destroy any productivity you might have at work...)

Edited by tiiiim

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. iPhone users, your battery is not removable, so tough luck on this one.

As wonder whether I could use your trick and cut an iPhone charging USB cable into a battery pack. I am not sure of the voltage and have no need to try it. But I have seen devices that use batteries for this purpose.

 

The way to tell is to look at the output voltage of one of your chargers. If it says 5V, then you are good to go. You may need a volt meter to determin which wire to solder (or otherwise securly connect) to + and which to -.

 

The great thing about the AA battery meathod is that it is cheeper than commercialy available units, has way more energy (mAh) than any I have seen (the most I have seen in a comercial unit is 750mAh compaired to 2500mAh in the Lithium rechargable AAs), maybe apple has some better ones, I don't know), and gives you a feeling of accomplishment. And if you bring some extra AAs with you, you have even more energy.

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. iPhone users, your battery is not removable, so tough luck on this one.

As wonder whether I could use your trick and cut an iPhone charging USB cable into a battery pack. I am not sure of the voltage and have no need to try it. But I have seen devices that use batteries for this purpose.

 

The way to tell is to look at the output voltage of one of your chargers. If it says 5V, then you are good to go. You may need a volt meter to determin which wire to solder (or otherwise securly connect) to + and which to -.

 

The great thing about the AA battery meathod is that it is cheeper than commercialy available units, has way more energy (mAh) than any I have seen (the most I have seen in a comercial unit is 750mAh compaired to 2500mAh in the Lithium rechargable AAs), maybe apple has some better ones, I don't know), and gives you a feeling of accomplishment. And if you bring some extra AAs with you, you have even more energy.

 

Absolutely agree with all the advantages of the batteries!! However, Apple are a pain in the arse, and if you have a look on the site I linked in the previous post you'll see that the iPod can't just be charged by applying 5V - it needs some sort of current down the data lines (USB has 4 lines: +, - and two data lines), and I suspect the iPhone does too!! If only everything were simple....

Edited by tiiiim

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Absolutely agree with all the advantages of the batteries!! However, Apple are a pain in the arse, and if you have a look on the site I linked in the previous post you'll see that the iPod can't just be charged by applying 5V - it needs some sort of current down the data lines (USB has 4 lines: +, - and two data lines), and I suspect the iPhone does too!! If only everything were simple....

 

Like Bill Gates sais, you can have it YOUR way, or you can pay extra and have it Apples way. :)

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You can get some decent silicone skins on e-bay for most phones for cheep. You should also install a lanyard; your phone is not as rouged as a hand held GPSr, so this will try to insure that it doesn't hit the ground.

 

My phone needs silicone, and wears rouge? Are you sure you're talking about a phone? :)

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Just to clarify this - I've also succesfully used 4 AA batteries to charge 5V items which would usually be charged from the USB port on a computer. WARNING: Although, as mentioned, some phones may not mind a 6V input, there is the chance you could fry the circuitry - the input is designed at 5V, not 6V. The trick is to use RECHARGEABLE batteries, as these are 1.2V each, instead of 1.5V for regular batteries (this is alluded to above, but not explicitely stated and I don't want people frying their expensive phones!).

To conclude:

4 AA non-rechargeable batteries = 1.5V x 4 = 6V = possible burnt useless gadget.

4 AA rechargeable batteries = 1.2V x 4 = 4.8V = happy gadget AND environmentally friendly (in terms of battery waste, anyway!)

 

Added a note for this. Good point. It is quite important to understand the risk before hooking 6V up to your 5V phone.

 

You can get some decent silicone skins on e-bay for most phones for cheep. You should also install a lanyard; your phone is not as rouged as a hand held GPSr, so this will try to insure that it doesn't hit the ground.

 

My phone needs silicone, and wears rouge? Are you sure you're talking about a phone? :)

 

Fixed. I never was a good speller. Only ever passed one spelling test in school.

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Ifound turning off the blue-tooth will help the battery life a little and may help with the GPS also.

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Ifound turning off the blue-tooth will help the battery life a little and may help with the GPS also.

 

Good call, but what even works better is shutting off the internal GPSr, and using a bluetooth GPSr puck. For quite cheep (<$70) you can get a GPSr puck that has rediculous sensitivity and accuracy.

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Ifound turning off the blue-tooth will help the battery life a little and may help with the GPS also.

I thought airplane mode shuts off all radios including bluetooth.

 

I built a Minty Boost USB charger. It has optional resistors on the USB data lines(pull up or pull down).

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Ifound turning off the blue-tooth will help the battery life a little and may help with the GPS also.

I thought airplane mode shuts off all radios including bluetooth.

 

I built a Minty Boost USB charger. It has optional resistors on the USB data lines(pull up or pull down).

The problem with airplane mode (at least on my phone) is that it also shuts off the GPSr.

 

Cool USB Charger! I was thinking of building something like that but with a regulator. I desided against it becouse of the energy lost in the regulator. Have you calculated how much is lost in the pull down resistor?

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Ifound turning off the blue-tooth will help the battery life a little and may help with the GPS also.

I thought airplane mode shuts off all radios including bluetooth.

 

I built a Minty Boost USB charger. It has optional resistors on the USB data lines(pull up or pull down).

The problem with airplane mode (at least on my phone) is that it also shuts off the GPSr.

 

Cool USB Charger! I was thinking of building something like that but with a regulator. I desided against it becouse of the energy lost in the regulator. Have you calculated how much is lost in the pull down resistor?

The Minty Boost uses a booster chip that is supposed to be much more efficient than a regulator. The pull up resistors for my Android phone are 100k, but I don't know what current my phone draws. I assume CMOS loads which would be micro-watts with no switching. I bought the Minty Boost because a Golf Course GPS app could use all the battery the way I play.

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Though I should add that for Windows Mobile phones GCzII, when use correctly so as to not break Groundspeak's terms of service, works great for back country caching.

 

By importing GPX files (pocket quaries, or GPX files generated by any other software packag (eg.GSAK)), you can load in all your cache information without performing the evil "screen scrap". You will want to save the cache list for quicker access in the future. Then, go into the cache description, and load up the "Static Maps" from google before heading out. The trick is getting maps that you want to appear. You can change the map zoom level in the static map settings (accessed from the initial screen, not from the static maps screen. You can also change what type of map it downloads (Street, Satalitte, or Terrain). This is changed from the windows regestry (HKEY_CURRENT_USER/Software/NICQUE/GCzII/REG_STATIC_MAP_TYPE_xxxxx). Each of the 6 map sizes can be set. Set each registry value as follows: 0=street, 1=satalitte, and 2=Terrain.

If you don't have a Reg Editor on your phone, you should realy get one. I use PHM RegEdit. It works great. There are also some good ones that you install on your PC and do the edit via USB. That is good if you are at home, but I like to do things on the go.

 

I have my maps set so that the huge and large map is the street view as zoom levels 12 and 14. Then my middle and small maps are terrain at zoom levles 13 and 15 Finaly, my Pinpoint and Pinpoint 2 maps are the satalitte views at zoom levels 16 and 19. (there seems to be a problem is two maps are set to the same zoome level, so avoid doing that.

 

Anyway, do all of this before you set off into the back country. Once out there you will now have access to all of this information as it is stored in GCzII's data base on your phone.

Edited by Andronicus

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Ifound turning off the blue-tooth will help the battery life a little and may help with the GPS also.

I thought airplane mode shuts off all radios including bluetooth.

 

I built a Minty Boost USB charger. It has optional resistors on the USB data lines(pull up or pull down).

The problem with airplane mode (at least on my phone) is that it also shuts off the GPSr.

 

Cool USB Charger! I was thinking of building something like that but with a regulator. I desided against it becouse of the energy lost in the regulator. Have you calculated how much is lost in the pull down resistor?

 

I was flying recently and tried out the airplain mode. Turns out that it airplain mode leaves the GPSr available. That can be a great easy option to get the power consumption down.

Edited by Andronicus

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Interesting. What do you do about the pesky problem of no signal? I have cached plenty of places that when I look at my cell phone it says "Searching for system". Plenty of places it apparently found a system but does not display any bars and basically does not work.

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Interesting. What do you do about the pesky problem of no signal? I have cached plenty of places that when I look at my cell phone it says "Searching for system". Plenty of places it apparently found a system but does not display any bars and basically does not work.

 

I was right beside the window, and held my phone up to the window. I actualy proped it up behind my pillow (read as: coat), so it would track as I slept. Here is my track log on GPSed (opps, I deleted it already, it wasn't very interesting.)

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In another thread someone brought up the issue of gloves not working well on the touch screen of a smart phone. Here is what I have done:

 

I wear a thin base layer glove under my right hand glove (I also do this for ski race coaching so I can write in my note book). Just slip the main glove off, and keep the base layer glove on. My phone works fine with the thin glove on. I use a glove like this

 

 

Interesting. What do you do about the pesky problem of no signal? I have cached plenty of places that when I look at my cell phone it says "Searching for system". Plenty of places it apparently found a system but does not display any bars and basically does not work.

My previous post I miss understood your question. I thought you were talking about GPS in an airplane. As for no system...If you are planning to cache in an area you think there will be no signal (this is a thread about back country caching, so it is quite likely), you just need to load in you GPX or LOC file ahead of time. I use GCzII, so after loading in the caches back at home, I then download static maps from Google maps. These include the regular map, the Terrain map, and the satallite map. When doing real back country work, I also load up a topo map on OziExplorerCE. Then I import the GPX into that so that the caches are displayed on the topo map. This system works like a charm. I realy like to have multiple tools at my disposal, so I realy like this solution.

Edited by Andronicus

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I have recently discovered that some smart phones have a "assisted GPS" chipset. To work well, they need the cell phone tower network to assist the GPS. Without this they are susceptible to anything like clouds, trees, generaly not good. So, before you head out into the back country planning to use your phone as a GPS, make sure to try it with the cellphone radio turned off first. If it sucks (like mine does :) ), you should use a bluetooth GPSr. They are cheep and work great!

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there's different types of AGPS. the "good" kind will be a regular, full GPS chip, which will be "assisted" with ephemeris/almanac data downloaded via the data connection, which will greatly improve time-to-first-fix. the GPS will still be fully functional without data connection, but it will have a longer TTFF.

 

the other kind of AGPS is not a fully functional GPS chip, but will rather rely on the cell network to generate position data. this kind of not usable for geocaching.

Edited by dfx

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there's different types of AGPS. the "good" kind will be a regular, full GPS chip, which will be "assisted" with ephemeris/almanac data downloaded via the data connection, which will greatly improve time-to-first-fix. the GPS will still be fully functional without data connection, but it will have a longer TTFF.

 

the other kind of AGPS is not a fully functional GPS chip, but will rather rely on the cell network to generate position data. this kind of not usable for geocaching.

Here is a link to Wikipedia about the Qualcomm GPSOne chipset that is in most CDMA phones

 

That is the chipset that I have in my phone. In the Standalone mode (which I have been using quite a bit recently), it can get a GPS lock, but not a very good one. It usualy only gets 4-6 channels locked, and seems to be somewhat sensitive to interference from trees and cloud cover. Also, I would not feel comfortable using the phone in Standalone mode to generate coordinates for hiding a cache. (although, during benchmark tests it is still better than non-WAAS enabled handheld GPSrs)

 

If that is not systemic of the GPSOne chipset, it could be related to the GPS antenna. Lets face it, most smartphones do not have a super GPS antanna. Mine is a small printed trace on a cct board.

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I just got a new Bluetooth GPSr. The Qstarz Q818x. It looks cool, but more importantly has a sencitivity of -165 dBm. That is more that 2x as sencitive as the best SiRF chipsets. It doesn't seem to have the anoying static navigation feature. And it uses a micro USB port for charging. I love that because everything else I have is also micro USB. Now I don't need a dedicated charger just for the GPS.

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I just got a new Bluetooth GPSr. The Qstarz Q818x. It looks cool, but more importantly has a sencitivity of -165 dBm. That is more that 2x as sencitive as the best SiRF chipsets. It doesn't seem to have the anoying static navigation feature. And it uses a micro USB port for charging. I love that because everything else I have is also micro USB. Now I don't need a dedicated charger just for the GPS.

I looked at the features and am puzzled by this feature:

Less than 15-Sec. AGPS fix support : download almanac data to realize faster TTFF and positioning under warm start

 

Download from where? How?

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I just got a new Bluetooth GPSr. The Qstarz Q818x. It looks cool, but more importantly has a sencitivity of -165 dBm. That is more that 2x as sencitive as the best SiRF chipsets. It doesn't seem to have the anoying static navigation feature. And it uses a micro USB port for charging. I love that because everything else I have is also micro USB. Now I don't need a dedicated charger just for the GPS.

I looked at the features and am puzzled by this feature:

Less than 15-Sec. AGPS fix support : download almanac data to realize faster TTFF and positioning under warm start

 

Download from where? How?

I haven't used this feature yet. The idea is that you connect it to your PC. The software that you can download from the manufacture allows you to download some sort of file that loads onto the GPSr. This will allow the GPSr to get a GPS fix FAST (15s) for the next 7 days. Seems prety cool, but my main computer (which is a net book) doesn't have comm ports, so cant get the software working correctly. I should set it up on my PC.

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Seems prety cool, but my main computer (which is a net book) doesn't have comm ports, so cant get the software working correctly. I should set it up on my PC.

 

Your netbook doesn't have a USB port?

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Seems prety cool, but my main computer (which is a net book) doesn't have comm ports, so cant get the software working correctly. I should set it up on my PC.

 

Your netbook doesn't have a USB port?

Dosn't have a COM port. You need the com port drivers. For some reason you have to set it up as a standard com port, then switch it to a USB virtual com port.

 

Anyway, tried it on my PC, and same deal. Can't get it working. But that is not why I bought it, so I am not too conserned. I bought it for the rediculous sensitivity.

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Seems prety cool, but my main computer (which is a net book) doesn't have comm ports, so cant get the software working correctly. I should set it up on my PC.

 

Your netbook doesn't have a USB port?

Dosn't have a COM port. You need the com port drivers. For some reason you have to set it up as a standard com port, then switch it to a USB virtual com port.

 

Anyway, tried it on my PC, and same deal. Can't get it working. But that is not why I bought it, so I am not too conserned. I bought it for the rediculous sensitivity.

When you install some manufacturer USB drivers they appear in "device manager" under COM ports. They are virtual ports no COM port connector needed.

 

I am very much interested in this unit because my Captivate GPS is worthless until Samsung fixes it.

 

I found out how to use the unit here.

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Seems prety cool, but my main computer (which is a net book) doesn't have comm ports, so cant get the software working correctly. I should set it up on my PC.

 

Your netbook doesn't have a USB port?

Dosn't have a COM port. You need the com port drivers. For some reason you have to set it up as a standard com port, then switch it to a USB virtual com port.

 

Anyway, tried it on my PC, and same deal. Can't get it working. But that is not why I bought it, so I am not too conserned. I bought it for the rediculous sensitivity.

When you install some manufacturer USB drivers they appear in "device manager" under COM ports. They are virtual ports no COM port connector needed.

 

I am very much interested in this unit because my Captivate GPS is worthless until Samsung fixes it.

 

I found out how to use the unit here.

I will give that a try again. When I installed the drivers, I didn't see them appear in the device manager anywhere. Maybe I did something wrong.

 

Anyway, I am loving that unit. I would definatly endores it.

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I just got a new Bluetooth GPSr. The Qstarz Q818x. It looks cool, but more importantly has a sencitivity of -165 dBm. That is more that 2x as sencitive as the best SiRF chipsets. It doesn't seem to have the anoying static navigation feature. And it uses a micro USB port for charging. I love that because everything else I have is also micro USB. Now I don't need a dedicated charger just for the GPS.

I was looking at this GPS again. Now that the Android Bluetooth GPS app is free, I was able to test the app out with my old clunky GPS and it worked fine. When I looked at semsons.com I found out they have upgraded to Q818xT. The "T" does positions at a 10hz rate instead of 5hz.

 

EDIT semsons is sold out

EDIT again semsons is not sold out. i was looking at the old non-T

Edited by John E Cache

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I just got a new Bluetooth GPSr. The Qstarz Q818x. It looks cool, but more importantly has a sencitivity of -165 dBm. That is more that 2x as sencitive as the best SiRF chipsets. It doesn't seem to have the anoying static navigation feature. And it uses a micro USB port for charging. I love that because everything else I have is also micro USB. Now I don't need a dedicated charger just for the GPS.

I was looking at this GPS again. Now that the Android Bluetooth GPS app is free, I was able to test the app out with my old clunky GPS and it worked fine. When I looked at semsons.com I found out they have upgraded to Q818xT. The "T" does positions at a 10hz rate instead of 5hz.

 

EDIT semsons is sold out

EDIT again semsons is not sold out. i was looking at the old non-T

Quick question: Why do you need 10Hz possition data? I never even use the 5Hz. Seems like just a wast of battery. If you were racing dirt bikes or something OK, but geocaching?

 

On another topic, I just installed Android as a second boot option on my Windows Mobile phone. What is with the crummy bluetooth support. Why on earth do you need an app to trick your phone into using a bluetooth GPSr? And if you want to use it for more than 10 min, you need to pay? I think most of my caching will be done with Windows Mobile. My analysis: Android = Fun; Windows Mobile = Get it done.

Edited by Andronicus

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OK, I just got a WP7 phone (department of redundancy department?). The LG Quantum Optimus. Love the phone, but no SPP (bluetooth Serial Port Profile), so no external GPS, and the internal GPS either sucks flim canisters, or has serious static navigation. So far, I havn't been able to do much caching with it. So, still using the old WM6.5 phone for geocaching.

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Ladyada, the designer/seller of the DIY Mintyboost USB charger, is on the cover of Wired magazine.

 

limor_fried_ladyada_WIRED.jpg

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I recently got a rubberised hard case for my Vogue from e-bay for about $10. It fits great, and really improves the ruggedness of the phone. It no longer fits into the provided belt holster, but I dont' use that when geocaching anyway.

 

I also have installed velcro on my back pack and on the back of the hardcase. Now I can 'slap' the phone onto my backpack strap, and it stayes in place. I still use a lanyard incase the velcro gives way, but now I don't need to use the beaner that I had to keep it from swinging around.

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