GPS information shipped with Psi-Mapper/GB v6.0 and family --------------------------------------------------------------------------- If you're a die-hard Psi-Mapper fan from the old days (i.e. before a year ago!!!) you may be happily using Psi-Mapper as it was originally intended, as a standalone Geographical Information System. And very good at this it is too. What's rather caught the public's imagination in recent years has been the possibility of hooking the Psion up to a GPS (Global Positioning System) unit, which are now available for a few hundred pounds (though don't buy the cheaper models) and which are in many cases smaller than the Psion. In case you're not sure what a GPS is, it's a small unit with a built-in aerial which receives positioning information from the american GPS satellite system (see picture) to tell you your current latitude, longitude, velocity, altitude etc. By hooking the two together the possibility exists to use the Psion as a flashy real-time moving-map display. With a GPS sitting on the dash-board, and happily chucking out latitude, longitude, bearing etc down the wire into your Psion, you can now 'select' this a town or overlay item, leave the Psion ON (or turn it ON when you actually need to, of course) and it will show you, in real-time, a black cross showing your position, a bearing line to show your current direction of travel, and estimated time of arrival at the place of interest! Cool, eh, although in Psi-Mapper/GB's case you have to allow for the fact that things are only done to 1km accuracy. Of course, if all this seems like whimsical gadgetry to you, you're probably right, but then I like gadgets! Note that ETA etc are calculated using your set average speed in your personal preferences. I've tried using actual speed from the GPS etc, but so far the results are just as transient and and/or approximate as using a set average ... watch this space ... So what do you need if you want to try all this out? * Psion 3a/3c/3mx palmtop with 150k of free system memory (100k needed by the program, and 50k margin for other programs you might start and stop during the running of Psi-Mapper) * Installation of appropriate latest version of my Psi-Mapper software for your country (GB, Ireland or France) * 3a users: a 3-Link cable (or at least the part with the 'podule' on) 3c/3mx users: the serial cable plus a 'null-modem' adapter * GPS receiver with NMEA 0183 v1.5 or higher interface (one of the Garmin units is ideal) and data cable. Also worth thinking about is integrating power leads for your Psion and GPS into the wiring if you intend to run them both for long periods! Note that the Psion doesn't *have* to be on all the time, you can just turn on when you need a 'fix'! Acquiring the above ------------------- I'll assume you already have a Psion and a serial cable of some kind, or you probably wouldn't have got this far! First item on your shopping list is to buy a GPS. Any of the Garmin units will work fine. In theory, other makes should also work, but not all manufacturers implement the NMEA standard properly, so watch out! Next get the manufacturers data cable for your GPS. This will usually come either with bare wires on the end or with a 9-pin PC serial connector. 3a owners: You need to make up, or get made, a cable to go from the GPS data cable and/or connector to the Psion podule. You *can* connect the end of the PsiWin lead to a null modem adapter to the GPS data cable, but that's an awful lot of wiring to have lying around when you're using the kit! The more convenient way in the long term is to get a 9-pin mini-DIN connector from your local Maplin store and to solder it on the end with the bare wires (i.e. chop off the PC connector if you have one). You can find the pin-outs needed in the PsiWin and GPS manuals. Basically you connect the GPS's transmit line to the Psion's receive and vice-versa, plus of course connecting the two earths together as well. 3c/3mx owners: The PsiWin cable ends in a 9-pin serial connector, which will look similar to the data cable connector supplied by the GPS manufacturer. The trick on connecting the two together is to make sure that the Receive and Transmit lines are swapped over. You can either make up a Male-to-Male adapter yourself, swapping pins 2 and 3, or you can try buying one ready made-up from a computer shop. Ask for a 9-pin M-to-M null modem adapter. Getting the GPS link working ---------------------------- Assuming you now have all the bits you need: 1. Plug everything in 2. Start up the GPS and position in your car to get good satellite reception. I find it works very well wedged on top of the dashboard, but if you have a heated windscreen this may be a problem for you, as the mesh of wires can block the signal. 3. Start up Psi-Mapper and go to the map you want the moving map icon displayed on-top of, and set your required sticky displays/options. If you're wanting to try out the ETA/Distance left option, choose your settings in the 'Moving Map Settings' dialog, and 'select' a destination (place or overlay item) by 'find'ing it in the usual way. When all is ready, select 'GPS Moving Map' from the right-hand menu. 4. If all is well, you'll see one of two icons on your map. Either a cross-hair showing current position or a 'Poor GPS' icon. The latter will appear whenever your GPS's output quality deteriorates to warn you that it doesn't really know where it is anymore. Try waiting or re-positioning your GPS .... 5. If the cross-hairs get too close to the edge of the screen, the map will re-centre itself and stay in 'GPS Moving map' mode. Have fun! Extra notes ----------- * If you should blow anything up or injure yourself in any way, please note that I take no responsibilty whatsoever for use of this software product! And if you're driving, keep your eyes on the road! I mean it! ONLY USE THIS PROGRAM ON THE MOVE WHEN SOMEONE ELSE IS DRIVING. IF YOU *DO* USE THIS ALONE ON THE MOVE, I WILL NOT BE HELD RESPONSIBLE WHEN YOU CRASH HEAD-ON INTO A JUGGERNAUT!!! * Technical one, this. Your GPS map datum should be set to WGS 84, if it's not already! Also, the NMEA version supported by Psi-Mapper is 0183 version 1.5. Psi-Mapper normally gets its information from the NMEA sentence $GPRMC, so if your GPS doesn't output this word you're last hope is to go into the moving map settings dialog and select 'Magellan (Position only)', which tells Psi-Mapper to go for the lowest common denominator and use $GPGLL instead, although this only gives position and not velocity or heading. Worth a try though, if you're having problems! See also my guide on troubleshooting GPS operations, below. --------------------------------------------------------------------------- Troubleshooting GPS operations --------------------------------------------------------------------------- So, you've been trying out Psi-Mapper on your Psion with your new GPS gadget. And it doesn't seem to work, either at all or terribly reliably ... Well, you're in the minority, because there are lots of people out there using it all quite happily together, but I accept that what with all the things that could go wrong, a few brief notes might be in order! --------------------------------------------------------------------------- Things to think about and look out for: * Are you using the latest version of Psi-Mapper? If not, why not? * Is your GPS 100% compatible with NMEA 0183 v1.5 and above? Psi-Mapper needs the $GPRMC word output every 2 seconds or more frequent. The best way to check what your GPS is outputting is to install the 'Comms' app on your Psion (you'll find it on the 'C' drive on a 3a), set the parameters to 4800 baud, 8 bits, no parity, no handshaking, and see what appears on your screen. You may find it useful to capture some of this output to a text file for later analysis, or for sending in for diagnostic purposes. Garmin GPSes seem to meet these criteria very easily, other makes tend to be more non-standard. In particular, the Magellan GPSes only output sub-sets of the NMEA standard data sets. If you've got a Magellan, set it to NMEA mode 'B' and make sure you're using v3.9 of greater of Psi-Mapper/GB, as I've been tweaking the code to work more reliably on the Magellan's cut-down NMEA signals. If you don't think you can get your GPS to output the $GPRMC word at all, but it *can* do $GPGLL, then go into the moving map settings dialog and select 'Magellan (Position only)', which is better than nothing! * How are you linking the two together? Are you 100% sure the pins/wires in your connections aren't shorting or dropping out? Are all the cables pressed fully home? Using the pin-outs given in the GPS and 3-Link manuals, try 'buzzing out' the cables you're using to ensure that the signals are going where you think they are! * Make sure your GPS's output is in the right NMEA mode. For example, the Garmin defaults to using its own proprietary GARMIN/GARMIN mode, and you need to change it to NMEA/NMEA ...