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Getting Gps Signals Onto A Pda


lordelph

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I'm steadily going paperless, my last outing I used a Geko 201 for "an arrow" in combination with a iPAQ 5550 for mapping and cache notes with MM/GPXSonar.

 

It was great, I just needed more hands :rolleyes:

 

So it's time to get my iPAQ picking up GPS signals. It seems to me that adding a receiver to the iPAQ itself isn't going to be great for battery life, plus I guess it's got to re-aquire satellites every time I switch it on?

 

So a bluetooth GPS seems the way to go - it can hang around my neck, stay locked on while I walk, merrily beaming away coords which my iPAQ can pick up whenever I switch it on.

 

The TomTom Bluetooth GPS (SiRF Star III) seemed to fit the bill.

 

Anyone use a similar setup or has other recommendations?

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We started a similar thread on here about a week or so back. Recommendation was the BT338 bluetooth receiver. After further investigating this we would recommend that you ensure that the "Static Navigation" function is either disabled or capable of being so. Basically if you're walking too slowly the accuracy is lost and it takes a finite time for the GPS to "catch up". We don't understand the reasoning but it's is now obvious to us that a number of modern GPS receivers have this "function".

We've gone down the other route and acquired a connector to run our ancient GP12XL with our PDA. Unfortunately the GPS broke the day the cable arrived so we're anxiously awaiting its return!!

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Thanks for all the suggestions. I was under the impression a bluetooth unit would help by being "always on" while I switched my PDA on and off. This way I get a complete track log and fast fixes, without having to leave my PDA on all the time.

 

Trouble is, most reviews I've read make reference to bluetooth receivers powering off when the PDA powers off.

 

Is there any way to force such units to stay on? Sounds like if I want to save PDA power I've got two devices to power up every time I want a coordinate fix.

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I use a similar set up.

 

Laptop with GSAK and Memorymap

Ipaq 5550 with GPXSonar, Memory Map and TomTom5.

Geko 201 for waypoint location.

 

The Ipaq works well with a bluetooth receiver. Mines a Pretec datalogging version. When you get home you can download from the datalogger and convert to a NMEA file to view your trip in MM. Handy for retracing steps later or for passing on routes to others. (The datalogging versions are coming down in price now, considerably so since I bought mine !!)

 

The only thing that annoys me with it is the need to reconnect the bluetooth connection when either MM or TT is shut down, but BT splitter software would resolver that issue.

 

The combination of the Ipaq with MM and the Geko gives an accurate way of finding a location and being sure to stay on rights of way etc...

Having found a cache, TT then gives an accurate (fastest or shortest route) to the next location.

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Actually, there's something I didn't consider - I guess a typical cheap bluetooth unit doesn't actually keep a tracklog you can pull off it later?

 

Having a tracklog is nice, but thinking about it, the only time I find them useful is when I've been in the car and wanted to know where the hell I went wrong when navigating "by nose". If I'm using a PDA in the car, I guess that can be keeping a tracklog for me!

 

Right, I'll make sure my chosen unit stays switched on and take the plunge!

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Hmmm.... my current BT unit, a dirty cheap TFAC one stays on until you turn it off. I'm looking to replace it with one with a Sirfstar III chipset and wouldn't be amused if it turned itself off.

They only turn off if the PDA or other device is powered down for a period of time (Usually around 5 minutes).

 

I when I am caching I stick my PDA in my pocket and leave the Bluetooth switched on it works for hours without a blip.

 

I use the PDA solely for mapping and a spare GPS if needed, my 60CS retains all it's tracklogs so have no need for the BT device to maintain that also.

 

I cached in the Wirral for around 7 hours and the PDA was on all the time as was the BT device and not once did the BT GPS turn off or battery run down on the PDA.

 

Data logging receivers are very nice but there is only so much a track can do, and 2 lots is usually overkill.

 

Moote

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Mine stays switched on (till the battery goes flat - not often with a car charger permanently connected), it's only the bluetooth connection that's dropped when the application using it is stopped (i.e. shut down MM or TT).

So BT splitting software will resolve that issue.

The track logged by MM on the Ipaq can be saved as an MMO, so, yes, the datalogging facility is a additional luxury.

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I disagree, Moote, mine just stays on until it's battery goes flat. If I pull in at home of an evening taking the PDA away and turning it off, it's still on and locked in the morning.

Sorry rutson, I meant mine only turns off after around 5 minutes of disconnection.

 

There is a problem though with draining batteries till they die, as this warps the internal structure or the battery and lessens its life. This tends to be why a mobile starts to not hold it's charge as long as they used to. This is more severe in lithium batteries, and usually more expensive to replace.

 

Moote

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My Holux GPSlim 236 stays on when turned on and goes off when turned off only,uses sirfstar3 and claims a 10 hour battery life.

I'm impressed with it so far.

But my point was that letting a battery discharge till it dies is very bad for a battery; It can seriously reduce it's life. If you allow this to happen the plates warp and can strat to touch. So Auto shutoff when there is no Bluetooth signal for 5 mins is a good idea.

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Lordelf

 

I use the TomTom Bluetooth GPS and it is a pain that it powers off after 5 minutes. It also appears to do this static navigation "function" so I generally use my Garmin for the last few feet. It was also a pain to find the GPS didn't work yesterday morning but Ebay came up trumps and a new one arrived this morning. I will now find out what TomToms customer service is like for a guarantee replacements.

 

Having said the above the TomTom is superb at holding a signal, it works really well when my Garmin Vista would totally give up, in fact the only time it has not given me a fix is in long tunnels. The internal battery life is great and it is very small. Also having to switch it back on is not as bad as it sounds as it obtains a new fix very quickly.

 

Hope that helps.

 

Dave - The Gecko's

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My Holux GPSlim 236 stays on when turned on and goes off when turned off only,uses sirfstar3 and claims a 10 hour battery life.

I'm impressed with it so far.

Same as mine, great unit.

 

Did you know tesco's stock a compatible battery for only £9.99 ? Good bargain. Its 100mA less then the original so a little drop in usable charge life, but less time to charge. Nice to have as a spare anyway.

 

I run my constant, regardless of what others have said... the battery will be fine running that way. If you really wanted to have thing power off everytime you shutdown PDA then you turn on the "Power Saving" via the HOLUX utility software.

 

THE GPS WILL STOP FUNCTIONING BEFORE BATTERY IS TOTALLY FLAT.... BY DESIGN, SAME WITH MOBILE PHONE... THE BATTERY IS NOT REALLY 'FLAT' JUST HAS DROPPED BELOW THE THRESHOLD REQUIRED BY THE DEVICE, NO DAMAGE OCCURS.

 

If you were to take the 'flat' battery out and then totally discharge it with a lamp across it contacts (or similar method) then maybe there would be the issues that have be claimed.

Edited by stonefisk
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THE GPS WILL STOP FUNCTIONING BEFORE BATTERY IS TOTALLY FLAT.... BY DESIGN, SAME WITH MOBILE PHONE... THE BATTERY IS NOT REALLY 'FLAT' JUST HAS DROPPED BELOW THE THRESHOLD REQUIRED BY THE DEVICE, NO DAMAGE OCCURS.ctuallty

Actually the information about batteries I gave out was originally from a friend who is a Chemist working for CMP Batteries, part of the Exide Technologies Group. I have just phoned to clarify some facts.

 

He have just correctly informed that a total drainage of any battery is unhealthy for the battery as this causes distortion on the elements inside, it is therefore inadvisable to allow any battery to totally discharge. I was also informed that devices like mobile phones have little in the way of protection for this, yes they stop functioning way before the battery is totally drained, but they still carry on slowly using the little stored energy available. This the reason Apple iPod had an early design problem with batteries.

 

He cited an example for people to cast their memories back to, "Suddenly your phone last 2 days on a charge and not the 7 or so, and when you cast your mind back it is usually just after a recent full discharge of the battery"

 

I'm not starting a debate on this I just feel that it is correct to inform people about this as a battery for a BT GPS can cost around £15 - 20

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On the Static Navigation feature, the BT338 that Moote and I use doesn't now have this problem, so is useable at walking pace (or slower).

This is a feature to help stabilise position when stationary in a car (waiting at traffic lights, for instance). For walking use, it had to be turned off using some tricky software, otherwise it would cause your position to appear stationary if you're searching for a cache on foot.

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I was always told that recharging a mobile battery from half full on a regular basis was bad for it that it retained a "memory" and wouldn't hold as long a charge as normal. The way around this was to let the battery completely discharge every now and then and give it a complete recharge from scratch to get rid of the "memory" effect. So are you now saying that this is a bad thing?

 

Confused :ph34r:

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The best GPS Bluetooth device that I know is the Globalsat BT 338

I can vouch for this model, I've used mine for 4 months now without fault - better accuracy that my old Garmin GPS 12 and fast acquiring etc. When using with TomTom Navigator 5, it's so sensitive that I can turn it on and leave it in a cubby hole under the dash. It still tracks my position with no loss in signal quality, even through the dashboard and body of a Freelander!

 

Recommended. :ph34r:

 

PS - I got mine for £70 inc. P&P off ebay .. although it was from Hong Kong. Waited about 1 week.

 

James

Edited by Team 'James W'
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Actually the information about batteries I gave out was originally from a friend who is a Chemist working for CMP Batteries, part of the Exide Technologies Group.  I have just phoned to clarify some facts. 

Oh so you must be right then. :ph34r::ph34r::ph34r:

 

When my lithum powered devices turn off they draw no current what so ever. And as stated you can force totally discharge beyond that point. But yes, the lithum battery prefers a partial rather than a full discharge with frequent full discharges avoided if possible.

Edited by stonefisk
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I was always told that recharging a mobile battery from half full on a regular basis was bad for it that it retained a "memory"

 

Confused :ph34r:

In the past....(say 5 years ago) , yes that is correct where the batteries where primarily in NiCad.

 

These days the use of NiCad has declined.

 

NiMH batteries is almost never affected by the 'Memory Effect' (Voltage Depression). Li-Ion batteries are not affected at all.

Edited by stonefisk
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I was always told that recharging a mobile battery from half full on a regular basis was bad for it that it retained a "memory" and wouldn't hold as long a charge as normal. The way around this was to let the battery completely discharge every now and then and give it a complete recharge from scratch to  get rid of the "memory" effect. So are you now saying that this is a bad thing?

 

Confused :huh:

The memory phenomenon is only experienced by Nickle Cadmium batteries Nickel Metal Hydride and Lithium Iron batteries do not have this problem. These days most small devices tend to use Lithium Ion batteries.

 

Edit: Think that my mate will be fed up with me phoning soon :)

Edited by Moote
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Actually the information about batteries I gave out was originally from a friend who is a Chemist working for CMP Batteries, part of the Exide Technologies Group.  I have just phoned to clarify some facts. 

Oh so you must be right then. :):):huh:

No I'm not right but I suspect someone who designs batteries has a greater knowledge than any of us, that is why I asked him for the information.

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Edit: Think that my mate will be fed up with me phoning soon :huh:

I just look in the notes and books from my Electronics Degree, and then there is Google.

I think I would trust my friend as much as I trust Google; after all he is employed to know about batteries and there usage, and how much chaff can you drag up on Google?

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I think I would trust my friend as much as I trust Google; after all he is employed to know about batteries and there usage, and how much chaff can you drag up on Google?

Well google does indeed help me to research and confirm that my particular model of phone does not draw residual current beyond the threshold of when its battery protection system has powered the device down. Off is indeed OFF.

 

Has the *chemist* tested many brands and models of phones as well other such powered devices? If so, would they care to publish the results as that would make for great reference on the Internet.

 

Such protection characteristic is per Brand/model based. Good after sales ploy or bad design to have a device that ruins its own power source from normal usage.

 

If my GPS device does or does not draw current to the bitter end is for a matter of testing or contact with the manufacturer.

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The memory phenomenon is only experienced by Nickle Cadmium batteries Nickel Metal Hydride and Lithium Iron batteries do not have this problem. These days most small devices tend to use Lithium Ion batteries.

I need to change my charging behaviour then! Thanks for the tips

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It just appears that you can't accept the argument, that a battery is at greater risk of damaged when being left to discharge. If as you suggest they do not discharge when a unit is powered down; why do all the instruction manuals tell you to remove batteries if the equipment is not going to be used for a period of time. It is due to the resistance placed across it terminals whilst still in an off position. And as the devices we are talking about have solid state switching that is far more likely to occur!

Edited by Moote
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If as you suggest they do not discharge when a unit is powered down; why do all the instruction manuals tell you to remove batteries if the equipment is not going to be used for a period of time.

More to the point, if using a device to the point of battery exhaustion is going to damage the battery why do no instruction manuals say "under no circumstances should you allow the battery to become fully discharged"?

 

Modern battery technology is very good, I have many gadgets which use all kinds of batteries, some NiMH, some Li-ion and some Li-ion polymer. I use them and abuse them to suit my lifestlye, not what the men in white coats in the lab say and I've never had any problems with any of them.

 

I would certainly find it a PITA if my gps switched off every time I switched off my pda, and I have never given a moments thought to the consequences on my battery of letting it run down to the point of non operation.

 

This is probably just another one of those times when the appliance of science doesn't quite meet up with what happens in the real world.

Edited by Cryptik Souls Crew
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I would certainly find it a PITA if my gps switched off every time I switched off my pda, and I have never given a moments thought to the consequences on my battery of letting it run down to the point of non operation.

My Bluetooth GPS does not switch itself off when I turn the PDA off it turns itself off after 5 mins of No bluetooth activity, which in my case is after I have switched the PDA off for good. It has not yet lost BT connection in the 3 to 4 months that I have been using it. So it has stayed on all the time I required it to. Simple really. And by the way, just looked at some instructions for my Speleo Technics FX-Ion and that informs you never to allow full discharge, these are designed to meet military and rescue services standards, so I think the company must have some good R&D, probably better than the average Google search or iPod manual.

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My Bluetooth GPS does not switch itself off when I turn the PDA off it turns itself off after 5 mins of No bluetooth activity, which in my case is after I have switched the PDA off for good.  It has not yet lost BT connection in the 3 to 4 months that I have been using it.  So it has stayed on all the time I required it to.  Simple really.

Mine has a switch, I turn it on when I want it on, and turn it off when I want it off, even simpler!

 

And by the way, just looked at some instructions for my Speleo Technics FX-Ion and that informs you never to allow full discharge, these are designed to meet military and rescue services standards, so I think the company must have some good R&D, probably better than the average Google search or iPod manual.

 

I looked on their website, they say "As the battery nears full discharge it will switch off suddenly." They advise you carry a spare, but not that you don't let it run down.

I don't doubt your comment about R&D though, not much R&D goes into a Google search in my house, I just pull up Google and type in my query.... :rolleyes:

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Further to our earlier postings... Garmin kindly replaced our 10-year old broken GPS with a brand new one at no cost! We then plugged in to the IPAQ using a cable we purchased from GPSBITZ and our position immediately appeared on Memory Map. It's amazing! The cable joining PDA and GPS also feeds power from the car so batteries aren't used whilst we're mobile. All great fun.

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Mine has a switch, I turn it on when I want it on, and turn it off when I want it off, even simpler!

 

Oh yes mine does that also, it has an on off switch! But if I have been out and forget turn it off and also forget the recharge, It still works in the Morning as the Battery is not discharged. (I think a major advantage there)

 

I looked on their website, they say "As the battery nears full discharge it will switch off suddenly." They advise you carry a spare, but not that you don't let it run down.

I don't doubt your comment about R&D though, not much R&D goes into a Google search in my house, I just pull up Google and type in my query....  :lol:

 

They advise a spare because if you are in a dangerous situation then a spare lamp should always be carried, not a spare battery, a spare lamp.

 

Yes the new FX-Ion does have protection, but when I purchased mine in 1999 it did not, and the instructions I refer to are for that. Anyway to get back to the point how can someone who has not consulted an expert in battery chemistry (by the way I have) inform me or others that it is perfectly safe to fully discharge a battery, doing so is just like saying you don't care one hoot about other peoples equipment.

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But if I have been out and forget turn it off and also forget the recharge, It still works in the Morning as the Battery is not discharged.  (I think a major advantage there)

I used to worry about this too, then I consulted with a friend of mine who is an emeritus professor of neurology, particularly specialising in memory functions within the brain. He gave me some helpful tips on how to best massage my cerebellum to stimulate my memory, meaning I now never forget to switch it off.

 

I also spoke to Major Advantage, he said he was on duty with his batallion in the middle east at the time, and nowhere near your battery.

 

It might be an idea to see a doctor about the discharge...

 

I would furthermore like to take this opportunity to apologise to everyone who has suffered equipment failure due to my reckless advice. Just because 99.999% of people have no problems with battery operated devices which they allow to run down to the point of non operation does not mean it is safe to do so.

 

Im afraid that's me all out of troll food, so I'll step back and allow you to enjoy the feast and the last word. Ladies and Gentlemen, thank you, and goodnight!

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