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I bought a mobile GPS for the motorcycle a year or 2 back, and really haven't used it since I got my new(er) phone which has a better embedded gps. This portable unit is waterproof, and transmits driver instructions on the FM band. There was a small receiver which you'd mount to your helmet etc. Overall it was a great unit, except the battery was complete rubbish, with virtually zero lifespan. It just wasn't functional without supplied power from the mount-bracket which was wired to the bike battery.
So I decided to add my own power source so the kids could use it when we go geocaching.
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So many screws between me and getting this thing apart. It was built like a brick with nice solid rubber bushings for every component, and metal brackets compressing everything together.
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Finally cracked it open. (this is an out of sequence photo, but you get the idea)
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COMPLETE RUBBISH BATTERY!! 1000 milli Amp Hours. That's functional for MINUTES, maybe an hour when running a backlit LCD and Windows CE with the GPS application and receiver running. The spec is fine if the unit is idle...but worthless when in use while portable.
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So I made my own battery pack. I couldn't find a triple-AA pack at Jaycar, so grabbed 3x1's and stuck them together with hot-glue on a small aluminium plate I cut out of an old computer CD enclosure. ;-)
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Hot glued the battery pack assembly to the back 1/2 of the GPS unit.
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...and fed the wires through a small hole I drilled through earlier. I then re-soldered and heat-shrunk the original battery plug
At this point the very straight forward job was done. Put it all back together and VIOLA, 7500mAh battery pack (standard rechargeable batteries are 2500mAh/ea), and go have some fun with the kids.
However...during the process I either nicked, pinched, shorted-out, or otherwise destroyed the LCD screen. I was certain the unit was "booting" because I saw it flicker once, and small debugging LCD's on the PCB indicated it was working in its on/off/sleep states. I was VERY VERY angry at myself. This was a really straight forward job. Simple in every possible way. I was having a rare moment of actual...happiness...listening to music as I did this. Then **BLAM** you broke your $200 toy. Idiot.
So I'm pretty angry now. I walk up and down the hallway eating cookies by the hand full, then order a pizza to drown my sorrows in its pure awesomeness. /dramatic-effect.
I figure there's no way I can reasonably expect to replace the LCD. During a post-op inspection, I actually make things WORSE by shattering the glass screen that the touch-digitiser is adhered to (this is a second component, not the LCD itself)
Wow...I'm on fire.
In a fit of desperation I get the magnifier on the part/s, and write down their bazzilion-digit part numbers and try to find them online. I was really surprised to find them indexed on Google at all. Even better, a few places were selling them wholesale to importers from China, but only in orders of 5 or more. As I dig some more, it turns out the parts used in this GPS are actually really common Gizmologist project components, but I still can't find a source for single units.
Ebay? Wow some dude is selling them!!...from China. I ask him if he's selling the touch-screen as well. But replies he doesn't. Oddly, I find another seller with the touch-screen...but he doesn't have the LCD. So I order both (cost me ~$40 total) and put the whole project on hold for 10 days while I wait for shipping from both guys.
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And they arrive on the same day!! In the same boxes...with the same labels. And the same return address? I guess they were both drop-shipping. Oh well, can't really complain, I got the parts!!!
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I plug in the new parts, and I see light :-D Very very happy now. So glad I didn't destroy the little computer unit. Running on USB power at this point.
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MY first test with the new battery pack as source power. Works fine, as it should ;-)
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The unit doesn't have a speaker, but as mentioned earlier it does transmit audio via FM. There is actually a little speaker-out port on the PCB, so I decided to test it out. Unfortunately I didn't really have any lower-power piezo speakers to test it with, nor an oscilloscope to properly test the port. So I gave up on that (for now).
In this picture you can clearly see the speaker port just down-right from the battery-port. Same style plug. The FM antennae can be seen top left near the black alligator clip, connected by a short piece of grey wire. The SD card is standard SD, not micro/mini.
I'm just simply amased that in this day and age it's cheaper to produce this kind of product with an off-the-shelf mobile computer PCB, with shelf display parts, to run an essentially dedicated GPS unit as an application within Windows CE, rather than as a static firmware circuit. All for $200 bucks at a grocery chain!! (Aldi) I've played around with WinCE on this unit when I originally got it. I'm boggled by how powerful this 7yr old operating system is, and I still wonder how Apple is in 2011 able to get any market share with their i-products. I'm running a GPS "app" on this unit, I can web browse (albeit really hard with this actual unit due to limited input plugs...not part of its sale-design), watch videos, slide-show photos, listen to music etc from this 2004 operating system. The original iPhone was a 2007 release and "swept the world" with what was really just "off the shelf technology". Try and keep up guys ;-)
So anyway. Basic job complete. This puppy has "UNLIMITED POWA' " for the kids now :-D