Slashdot Mirror
Hackable In-Car GPS Unit?
gigne writes "I'm in the market for a new, in-car GPS/sat nav. I am preferably looking for one that has live, up-to-date traffic information and route planning that doesn't make you want to cry. I'm not quite dumb enough to drive off a cliff, but something that doesn't even try and lead me to watery doom is preferable. The only thing I absolutely must have is the ability to hack it. It would be preferable if it ran GNU/Linux, but given a convincing argument, I would be swayed to another OS. Without wanting the Moon on a stick, what is the best device that would offer a decent modding community and a good feature set?"
Tmobile G1 running telenav.
bam. done.
Companies comercializing GPS devices are in the business of making money. I am inclined to believe you would run into proprietary and legal stuff should you plan to hack or reverse-engineer the device. Maybe some provide an API?
Aeroespacio.org
what about the android platform. telenav, and soon garmin will be on it.
Everyone famously knows tomtom runs (GNU/)Linux, and uses FAT formatted memory cards, just ask Microsoft.
Sounds like you want something more than a TomTom. Peruse the forums at mp3car.com and you'll find tons of information. Build a computer in there and you can have whatever flavor of GNU/Linux you like. Add GPS and you're done. Add EVDO and you have Internets to watch pornhub while traveling down the interstate.
I own one of these and it is hackable. Good luck!
When I drove from California to NC, I wrote a custom app that read the GPS lat/long coordinates, searched a database of 5000 fast food places, gas stations, and hotels within 1 mile of I-40, so I could find where I wanted to go even if it was 70 miles up the road, and hit a great big button to search for it so I wouldn't wreck my car, and then enter the coordinates in the navsat program to start driving me there.
Does that count as hacking it?
I did it on my PocketPC. Does that mean Windows Mobile still sucks and is useless for hackers?
iPhone
I have a Navigon 2100, which runs WinCE but it is quite hackable. The whole OS and related data is stored on an SD card; you can simply plug it into an SD reader, replace the files, maps, everything.
Take off every sig. For great justice.
Many car GPS units use a cut down WinCE. There are plenty of these around, and they are cheap. I use a Binatone X350 to run XCSoar. MS can provide the development environment if you want it.
I also have a TomTom. I bought it because the OpenTom stuff meant there was a development environment for it. I never went further than getting a few simple non graphical progams compiled for it, but the information is all there if you're keen on development.
Randall Munroe had a cool python program on his blag at one point for a simple GPS program for linux. Can be found here
It runs Linux, uses mplayer for media output, and is very hackable.
http://www.webazar.org/tomtom/index.php
Tripmaster is the #1 3rd party app that you can install. There is lots of other stuff you can do to it too.
"The price good men pay for indifference to public affairs is to be ruled by evil men." ~Plato (427-347 BC)
Earlier TomToms had a developers kit. With the latest versions of the OS that offer many new features, like text to speech and use of faster aquiring GPS chips, they've removed the ability to do any kind of hacking. A real pity. I came into the game just a little too late. So I get the nice features, but not the nice hacks.
These posts express my own personal views, not those of my employer
Sure -- try a FreeRunner. Sure, it's nominally a smartphone but it's got your key requirements: GPS, decent graphics, networking, audio I/O, and ssh.
Lacking <sarcasm> tags,
I've been looking into this recently as well. Best bet I've found, in terms of "tinkering" ability is to use an Arduino and a GPS Shield (more details here). The two of these (and the GPS chip) will cost under $150, but allow you to code it to do whatever you want. Throw in a TouchShield and you begin to open up possibilities. The downside is the time/effort needed here. The "convenience" factor is not part of this solution... :)
I've just written a hackable gnu/linux satnav program that runs on a USB stick. It's called 'Moon'.
Disclaimer: No I haven't.
Garry Knight
the new garmin units plug in like a usb thumb drive and you have direct access to their .GPX data files. The files are in flat XML, heavily documented, and very flexible. (apparently garmin has gone away from NMEA/serial, good riddance)
They come with two pieces of software, one that runs locally on your computer and the other is a browser plugin that I assume gives java control over the same things. I was very impressed with the software, but it does have its limits. (such as building routes) But since the files are xml you can use any off the shelf standard .GPX editing program (there are several, and I recently wrote my own too) to edit things how you need to. Some are free, most are pay. But the software for the garmin is free with it.
You can't ssh into the thing, but as far as file/format goes, this is about as "open" as it gets. FYI I have an Edge 605, use it on my bike. It's got a really small screen unfortunately but those are the breaks for small and long battery life.
I work for the Department of Redundancy Department.
I think the market has lots of room for improvement. It would be nice to have, not just a GPS system, but an in-car computer. Imagine if the computer could hook up to OBD-II, odometer, speedometer, radio, rear-view camera, a cell/wireless network, and other in-car systems. It could track fuel usage on every trip, overlay Wikipedia geographic coordinates, log milage information for tax reasons, record traffic stops (even capturing a few minutes of video prior to the stop), and countless other things.
A good system would boot up in less than two seconds, start playing music where it left off, and instantly switch on a rear-view camera as soon as the car switches to reverse. Most existing systems have only a few of the aforementioned features, they tend to run fairly slow, and they have startup times that leave you wonting for music.
I think a feature-complete system would require a fast processor, a large display (probably requiring custom dashboard work), and a lot of wiring.
My own research turned up Navit which looks pretty good for the navigation piece.
The most hackable GPS I have seen and owned is the Omnitech 4.3 inch GPS unit sold at Staples. On a good sale day you could get the GPS unit for under $80, and some have even found them as cheap as 50-60. They run Windows CE5, and all of the files are stored on the SD card so it's incredibly easy to modify. There are already SD card images on the net that include multiple GPS programs like iGo8, TomTom, Nav N Go, Destinator, etc. and also come with a lot of games, programs, utilities, Office for PocketPC, etc. The Omnitech GPS can be had on eBay for as little as 70-80 dollars new if you can't find it in stores. If you cannot find an Omnitech unit, the next best thing would be one of the lower tiered Nextar units sold in Kohl's and Best Buy. I also own the Nextar 43NT (this is the one I use on a daily basis) and my GPS unit normally runs iGo8 as the GPS naviation program, and I also play games on it when I have down time, and have even been known to watch an XviD TV episode on the highway on long trips.
The downside to almost all GPS units though is that they don't accept SDHC cards. Theoretically 2GB is the maximum for a non-SDHC card to hold, but Transcend does market a 4GB non-SDHC card on Newegg for around $14 bucks. They all have about the same processor speeds and RAM though....the more you pay for the unit, the more you're paying for the software that comes on the device. Do yourself a favor and stick with the cheapie GPS and hack the unit to your satisfaction
The Nokia N800 and a Bluetooth GPS.
1. It runs GNU/Linux so very hackable (comes with a Nokia-written Debian-derivative, but you can install a completely free Ubuntu derivative)
2. GPS stuffs are in the bluetooth box so no legal issues
3. There is no 3
Or perhaps the N810, it has a (somewhat usable) built-in GPS (or you can use a bluetooth one again) and it comes with most of a car mount (you just have to buy the bit that fits your car). N800 might too though...
Get a linux PDA (Nokia n800/n810 or sharp zaurus?) or maybe even a small netbook, bluetooth or USB GPS and run navit (http://navit.sourceforge.net/) on it. Navit displays moving maps (from opensstreetmap) on screen based on GPS data.
Get a Freerunner. It's an open phone with: GPS, internet via gprs, accelerometers, full bluetooth, wifi, 640x480 touchscreen. It runs any of several flavors of Linux (including Debian or Android, but my personal choice is SHR) and there are already Free gps programs that use OpenStreetMap (TangoGPS or Navit).
It's about $250, IIRC, but of course you can carry it around and use it to browse the web and receive calls, as well as using it in-vehicle for navigation.
It doesn't get any hackabler.
. . . it fit's your GNU/Linux/Hackable requirements . . . I dunno about the "live, up-to-date traffic information and route planning " stuff. But worth taking a look at.
Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
What about something like an android phone, they come with GPS. Then you also have a pretty cool phone to go along with it. I have no idea what apps there are for mapping but I would hope there would be something good by now.
What exactly are you trying to hack the GPS to do?
I really would like an R2 unit / the earthly equivalent.
First, I have a penchant for getting lost. As in, it's happened in my own neighborhood -- GPS device, while in some ways it's a crutch, also helps me *learn* streets by taking me the (or a) correct way a few times. As the saying goes, sometimes crutches are useful.
Second, I like to drive long distances / cross-country (for instance: I plan to go east in not many weeks from now on this route -- and back to Seattle via a slightly less direct path -- ), and would like something that can fake AI pretty well as a travel aid. ("Infotainment!")
Right now I have a decent-enough (discontinued, middle-end) Garmin, which took me several GPS-buying attempts to settle on, and it does a lot of things well (interface is OK, and it plays MP3s). But a guy can dream ...
I know this is not yet a reasonable demand for products in my price range, but I'd like to be able to use moderately complex spoken demands / requests / ideas, Star Trek (or Star Wars, or Hitchhiker's Guide) fashion, some of which would require either a really big data store or (at least intermittently) an internet connection:
"Plot me a course to the nearest used bookstore, artoo."
"How much longer if I take a route with no tolls?"
"Does that Taco Bell have a 24 hour drive through?"
"What happened at this battlefield? Give me the short version."
"Play that interview from EconTalk.org about the difference between law and legislation, and then some up-tempo Bach."
"What are reviews like on this cheap motel?"
jrnl: http://tinyurl.com/c2l8yr / foes: http://tinyurl.com/ckjno5
It has a GPS and compass, wireless, maps and searching... And the full source code to the OS is available with a fairly good development environment, if you can cope with Java or wait for one of the other available scripting systems they're talking about. You want hackable? Do a "git" of the phone software source, and you can do a "make" to produce new firmware. With the exception of a few Google-only applications, like the gmail app, you've got everything you need. There are community members that are doing their own builds, I've had good luck with the jesusfreeke builds. I've written several applications with a friend of mine -- nothing GPS-based yet, but an IP address calculator and an app that turns the Android into a webcam, and will automatically take pictures and upload them to an HTTP or FTP server. See http://slackey.com/ for more information. The benefit is that if you can use it for your phone, it's not another device you have to keep with you and keep charged. The down-side is that it only works with GSM phone providers. The biggest thing for me has been that it's something I'd have to be carrying anything, for when I'm on-call. So, it's literally not another thing that I have to keep charged and with me. That's been the biggest issue I've had with the Palms and other GPS devices I've had, and the Nokia 770/N810. It's a GPS that is SO much more useful than the typical GPS. Of course, all IMHO. Sean
I just got a Pioneer AVIC-F700BT (http://www.pioneerelectronics.com/PUSA/Products/Navigation/In-Dash/AVIC-F700BT). It doesn't quite do everything you asked, but there are other models that add traffic updates, etc.
It runs Windows CE (bear with me here..), and has ways to boot into it. There are people that have hacked the firmware, and added various features to it - check out avic411.com. I haven't tried this myself, but it doesn't look overly difficult. I get the impression that community is not really full of "programmers" per-se, more just enthusiasts, so it's likely that someone who actually knows how to program would get quite far. (Note, I am a programmer, I just haven't had time to mess with my car stereo which works satisfactorily).
Pros: relatively cheap (note: the MSRP is $900-something, but it can be found for $500), has pretty decent maps, decent directions, plays MP3s from USB/CD/SD (and DVD, in some models), ipod interface, has XM/Sirius capability via add-ons, bluetooth with voice recognition (which works extremely well)
Cons: slow-ish bootup time (~7 seconds to playing music, another 7-10 before UI is fully available), music-related voice control features only work with ipod (eg, "play songs by ____" doesn't work on cd.. but you can say "next track" or "change source to FM" - which frankly, is kinda useless), playback from SD/USB won't resume right where it left off, it always starts the song over, fast-forward/rewind is frustratingly slow (both of these are probably fixable via firmware, or even hacking.. unfortunately, they contribute to mean I can't really listen to podcasts, which is one thing I was hoping for with the ability to use SD cards). Ships with a stupid "feature" where you can't change Nav destination/settings while driving (luckily, this is easily bypass-able by connecting an extra wire while installing).
I'm quite happy with it, honestly, and I'd definitely recommend the unit. Like I said, I haven't really gotten in to hack it yet (I likely will), but then again, I haven't really needed to.
Speak before you think
How much is your time worth?
Yes, you can screw around hacking GPS units. The question is, why do that instead of buying an ultramobile PC with GPS and navigation software?
Do you save money? No. Not if your time is worth anything. Also, if you're going to depend on this, say to equip your business or something, you have no guarantee you can do the same hacks when you replace the devices.
Do you learn anything? Well, sure, especially if you're the one who puts the time in to figure out how to do the hack. But less than you'd learn if you spent the same time just building software on a platform where the manufacturers are scheming to make your life miserable.
Are you striking a blow for freedom? Nope. You're sending your money to a manufacturer who's trying to restrict people's freedom. They don't really care if you manage to hack the thing, only that the process makes it worthless to most users. So maybe you should support folks who are marketing and supporting platforms, and save yourself a bundle of time too.
Of course, if the dedicated GPS units are better for their purpose than putting navigation software on an open PC, you can buy both; a GPS unit for navigation, and a UMPC with GPS for hacking. If your time is worth anything, you're still ahead.
I speak from experience, as an inveterate opener of cases and tweaker of things that are not supposed to be tweaked. It's only worth buying something to hack if the act of getting this thing to do something the manufacturer doesn't want it do has some kind of twisted appeal to you. One possible exception is if there is something unique about the hardware, which is certainly not the case for most GPS units. In fact they probably lack things you'll want, like certain interfaces. If there were a device that was amazingly cheap and known to be super hacker friendly, I might be tempted, but probably wouldn't bother. Where the manufacturer is trying tie your hands, why give them money for the privilege of spending your time escaping?
If you've bought one without the intention to hack it, and then you get the itch, sure go for it. That's a different story. But I think you'd be nuts to buy one for hacking if that's a high priority for you.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
There's a healthy hacking community for Pioneer AVIC in-dash units (http://www.avic411.com/). The current generation (F-series) is basically a Mio Windows CE 5.0 Navi that runs iGo 8.0 and interfaces to an AV board for sound out. It uses a Parrot Bluetooth for the handsfree but it's not a full BT stack so no A2DP. The interface Pioneer had an external software house design has been rather bemoaned for some frustrating "quirks", so there's a lot of motivation to hack the units at the moment. There is a way to launch external apps from the iGo script interface now and there's even an effort to write a new interface from scratch that launches from the SD slot (sort of like MioPocket for some of the PNAs). There may also be a way to use SDIO 802.11b/g wireless cards with the units that was borrowed from gpspassion.com.
Pioneer will be releasing a new series of in-dash units soon (X series) and a 3.0 firmware release for the F-series that apparently removes the ability to use the backdoor method many of us use to hack the unit, so if you do decide to get one make sure it's only got the 2.0 firmware on it.
-- "I have a great faith in fools. Self-confidence, some call it..."
What about a netbook with a built-in mobile broadband card? These can be had for $400 or less (probably much less if you can get the mobile provider to subsidize the device). Add a decent GPS software package that includes a USB receiver and you've got a ~$500 GPS that can do it all with no hacking required.
Hell, a high-end GPS unit with half the screen size will set you back the same. But with this setup, you can take it out of the car when you get to where you are going and have a handy little netbook.
http://mboffin.com/earthbridge/ this is something you may want to check out... B
I have a Magellan RoadMate 800 which runs a stripped-down version of Windows CE. With just a button-press combination you can view a full windows desktop environment with touchscreen behind it and run whatever programme you want. It's super easy as it has an SD slot and 20-40GB of internal memory to do just about whatever you want with it.
Yes, you can screw around hacking GPS units. The question is, why do that instead of buying an ultramobile PC with GPS and navigation software?
Talk about missing the point...
You know, I think your attitude is the problem with consumer electronics today. They give you GPS with maps and you think "hey! That's cool! Now I can get navigation!" Some time later they come out with turn by turn spoken directions, and you're thrilled with that too. And then you come here on slashdot and argue against the open products, because they might be hard for you to use, or people might put them to uses the manufacturer had not intended.
Look: people are clever. Give them neat gear with open interfaces and they'll put it to creative uses the manufacturers had never considered - and publish the source code for anyone to use. If the features are interesting, useful and most importantly, popular, they'll wind up in the next generation of the manufacturer's products and you will benefit. It's like having a half billion geeks working for free.
Fortunately for you and for the rest of us, most manufacturers have figured out that they don't have the corner on creativity and so they make open, or "hackable" interfaces that allow us to bend these devices to unintended uses that they can then adopt in your next generation product.
Help stamp out iliturcy.
Check out the Advent ADV3500PC GPS, it's a VIA 1GHz based unit, and is loaded. It's one sale right now @ Buy.com for $270. I have one sitting on my desk and it's one of the most fun toys I have owned in a while. Check out the thread below for more info: http://www.cocoontech.com/forums/index.php?showtopic=13829 Its main function is GPS, but it can do so much more. I also use it in a home automation environment, and considering getting a second one as a CarPC.
I was just talking about this with my wife today. We just got a Garmin, and it's nice and everything as a GPS and Bluetooth phone integration and has other useless stuff (Games and msn? UGGH) but it's not integrated into the car like it should be. What is wrong with the car manufacturers, why hasn't Apple done an iCar? If I turn up my music I can't hear the directions.
And having my car computer on the cellular network for web updates of traffic etc. Also having engine computer diagnostics on my screen would help. Also, having mileage and Trip statistics and memorys of places and cell phone hands free and ability to hook my USB drives up for mp3 jukebox... Don't forget voice recognition. And it could phone the ambulance if I crash. All in one built in unit.
But I guess it's too much to think someone would build it into a car where it belongs and it would *JUST WORK*...
So I will have to do like the poster is talking about and hack up my own system... And Linux is a great start.
I've heard a lot of people have had success with putting a Mac Mini in vehicles. There's even a site dedicated to it: http://www.macvroom.com/ Downside is that while the software hacking would be relatively easy (there's already GPS software for OS X), the hardware would be the hard part. You'd have to find a place for it in the car, as well as a touchscreen, and possibly a keyboard.
This signature serves no purpose other than to help you see which posts were made by me.
Seriously, the OpenStreetMap folks have this one figured out already. See their GPS reviews wiki entry on their site for your guide to what GPSs are hackable.
Furries make the internet go.
It runs Linux, Android has an SDK, it has Google maps and GPS apps for it, is open and low cost...
Look for an Omnitech unit, they were sold at Staples for $70 and very hackable. You can put basically any vendors GPS app on it and it runs WinCE . You can play games, run apps including media players.
Good forum for details is... http://www.techsmarttips.com
Hope that helps.
The first thing we need is free map data. All current maps have very tight legal terms, which makes this kind of thing impossible. Check out http://www.openstreetmap.org/, there might already be decent maps where you live. For navigation you can use TangoGPS but there are other programs available too.
Iphone has gps and you can do crazy stuff there ...
The Nokia N800 and N810 both run a version of Debian and can do GPS. The N800 (what I have) does not have the GPS antenna built in, but you can purchase an antenna from Nokia and connect via bluetooth. The N810 has GPS antenna built in. You can run the free maemo mapper (openstreetmap.org) or purchase a commercial product from Nokia (NavTech). And the Nokia N800 and N810 are great for lot of other things too. I teather the N810 using bluetooth and AT&T. With that you can create a port forwarding ssh tunnel and have any GPS daemon listening in on your coordinates from anywhere. A personal tracking app. See maemo.org. Regards, Delafield
All the stories about watery doom are almost nothing to do with the GPS and entirely due to the maps. The GPS can only give as good instructions as the underlying map data. Map data on highways is usually fine as they don't change much, many people use them and the information is easy to incorporate. Smaller roads change more often, there are lots more of them, and the company making the maps is less likely to keep completely up to date with them. Nowhere do I see how you intend to deal with maps.
Check out dashdq. It's an arm9 processor running linux and the source is available. Mine is still on the way so I can't say how hackable it is yet but it might be a good starting point.
http://www.dashdaq.com/
Or the new 3GS one. It has a GPS receiver, and there are a variety of applications which can utilize that to offer mapping and directions. Plus the backend is OSX - once you jailbreak it, you can ssh in and do all sorts of hacking.
If you did have the moon on a stick, and a sextant, and an almanac, and knew how to use them, you'd never be lost. Not so sure about the traffic updates...
Hey, almost any car GPS is going to be plugged in; I assume that if the Freerunner is an open phone, it probably uses some fairly standard power plug.
Of course, if you meant that the battery life using a car battery is about 1 hour, that's a more serious problem... :-)
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
killing the car battery in an hour would be a serious problem. Luckily that's not the case. But the FreeRunner is charged via a mini-usb port. Still you are right, a suitable charger cable can be found.
Try looking at the Nokia N810. Open source OS, has GPS run whatever you want...
GPSmid is a (not so nice yet) open source J2ME app for navigation. It wants to do all the dedicated boys do and seems to be making good progress. Disadvantages: hard or impossible to load big maps; openstreetmap is not perfect (yet); lots of features but also unfinished functionality.
If you show the app it is hard for people to belie it is J2ME and runs only in the phone.
gpsmid home page
The OpenMoko freerunner has a GPS... Just no decent navigational software that I know of...
The dash.net GPS is based on the Neo1973, but it is only partially open-source....
TomToms are linux based - download their source and change. GPL, it is what you're asking for...
I guess you'd need a volkswagen for this, but I really like the Volkswagen RNS 510. It has a hard drive, can store mp3's, play dvds or TV, and the map files can be hacked to include your own POIs. Now if someone would port linux to it ...
This isn't hackable but it's awesome:
http://www.waze.com/faq/
Works in Israel so far and they say that it will roll out to the USA soon. Doesn't require special hardware and the software is free (as in beer).
After the first few people, even my cheap USB keyboard has enough sharp edges to cause some damage!
I hold very few opinions. I hold information based on observation and fact. If you wish to disagree, please use facts.
I didn't know Hans Reiser could still post on /.!!!
I hold very few opinions. I hold information based on observation and fact. If you wish to disagree, please use facts.
Nokia makes PDA-like Linux computers - the N810 has a built-in GPS. I have an N800 and tether a GPS to it via Bluetooth. I haven't paid a dime for software. It runs 1,000s of linux tools in addition to Maemo-Mapper which is a navigation application.
It isn't limited to 1 process at a time like the iWhatevers. I routinely run 4+ applications including GPS and audio playback at the same time.
This is a general device that adds GPS, not a GPS device that adds general computing, so your expectations need to be set with that in mind. Source code for 80% of the OS and applications is available. There are proprietary portions as you get closer to the hardware, I've been told.
try GpsDrive + OpenStreetMaps on an automotive MiniITX kit. It'll fit into a stereo bay and draw about 20 watts, and is hackable to your heart's content.
Why not also your dishwasher? or the whole fucking car for that matter? Is there something special about something that contains technology and electronics that means hat it must be hackable and at the mercy and preserve of idiots like you? I suppose you'll decline all responsibility and run for cover when your amateur hacking causes a car crash? and would be the first to start bleating when someone else hacked your set, no? Get a life and apply your talents (if you really have any) to something useful, for pity's sake
It depends on how you look at it. If, when I say I have nothing to hide, I mean that I do not believe any of my actions to be immoral or unethical, I could be making perfect sense, depending on my attitude towards avoiding societal consequences (someone might even feel it is important to bring attention to such laws; I don't think I would risk much prison time to do such).
Nerd rage is the funniest rage.
I've very happily used an Openmoko Freerunner last december during about one month, which comes with what I believe i the only open-source GPS hardware (in addition to being linux-based).
I went into Openstreetmap which of course can be both downloaded for offline use and upgraded since you can record paths, and definitely was a happy camper, until a crease appeared in the ubernice touchscreen, soon resulting in 50% of the touch capacity being down (ie the phone is unusable).
I intended to prepare some startupscripts to turn it into just a nice GPS... and never had time to do it :-(
I'd say it's a very nifty GPS, OSM-based, being undertood that it won't feature the tomtom-like autoupgrade of GPS constellation ephemerids which accelerate the first acquisition (in other words: it'll converge more slowly than the average dedicated car-GPS)
In case you're interested I could offer you my broken package for basically the cost of packaging/sending (say 50E?), but be really aware that the touch function of the screen is dead, you must program it ith a keyboard or via SSH...
Herve S.
I suggest a Magellan 4250, and MioPocket 3.0(http://rapidshare.com/files/247598756/MioPocket_3.0_Release_49.zip) or Lite (http://www.freewebs.com/miopocket-lite/). Free unlocking software for WinCE devices. I've had it on my GPS for a while I love it. It can play Divx,Xvid, you can put screen into landscape mode and read PPT/DOC & PDF files, mp3 player, you can also load third-party gps software, it comes with Beeline GPS and several others, and it allows you to retain the original firmware.
Uhhh how did this post make it on slashdot?
Oh, and one thing to look for in a GPS is one with a PPS output. This adds a lot of fun to any project as while it is idle, it can function as a stratum 2 clock for your network.
And they already wrote it, it's called Places.
I have an IPAQ 312, which has a US equivalent,
the 310. This is easily hackable but is still windows CE. You finish up with a Win95 type desktop look.
I have got it to run TomTom6 and the open source glider navigation program XCSoar,
which is very good indeed.
As another poster mentioned TomTom units run linux.
There is a lot of good info on the gpspassion forum regarding hacking lots of differnet nav/gps devices.
How about Bug Labs. It doesn't get much more hackable than that.
Unexpect the expected!
Hacking your navigation device will be HOT after the community develops three things.
If those three things happen I could see a ddwrt type of pack being developed.
There is little incentive to hack GPS or PDA devices:
One that is done and a certain mass of users are using the above data and algorithms; maps would become dynamic information sources constantly updated with road changes and maybe even real time road closures, road speed data, one way street information and other valuable tidbits. More advanced devices with accelerometers could make that data even clearer for eventual technology like eco routing.
If you have to have a hackable linux navigation solution now get a cheap umpc or netbook running igo 8 or another nav engine on wine.
I have the mio c320, unlocking which was a breeze.
for around 200$ you can get the ones equipped with traffic.
Mio is however just one brand, but due to excellent community built around unlocking, its one of the easiest to hack.
I suggest you head over to gpspassion.com forums to check it out.
My Aurora : http://www.youtube.com/watch?v=o91ZsGwJYyg
FB : https://www.facebook.com/TanveersPhotography