|
Palmtop
GPS on a Psion 5mx without using a car!
Introduction
This might not sound too difficult but, even if you were up
for the challenge, why would you want to, anyway? Well, I’m sure you’ll find a reason! Actually making all the bits work together is not that difficult,
once you’ve got them all, but getting the parts took me some time, as you’ll
see below.
I had been intrigued by the possibilities of GPS for some
time, having seen the Garmin-type waymarking devices and output in use by
surveyors at the office. This is for a
slightly different purpose than the in-car GPS commonly referred to as “Sat
Nav” that is now all the rage. What I
wanted was a sort of combination of the two ideas. Why? Well, I’ve been sold
on the idea of mapping on my Psion for some time – it’s incredibly useful for
finding addresses in an unfamiliar town or city (much quicker than paper maps)
and I’ve had a general fascination for all types of maps since I was very
young. Needless to say, I’ve got
RealMaps and MapGB on my Psion as well as the planning programs I mentioned
above. I’ve also downloaded many
different maps, map types and map data from as many free sources that I’ve been
able to find. So it was natural that,
since GPS was available for the 5mx, I should try it out. I was further spurred on by Martin’s article
“GPS on a netBook” but decided that the route planning approach using the
Palmtop GPS receiver looked a more straightforward solution than the
Garmin-style approach especially since the latter involved making up cables to
join the two devices together! Martin’s
approach of plugging in a CF GPS receiver won’t work with the 5mx of course, so
that approach was out. So this is what
I did.
First Steps – Mapping and Route Planning
First I bought the software, Palmtop Route Planner (1998
version) and Palmtop Street Planner (1999).
I later upgraded Route to the Millennium version (the newest I could
find) and replaced Street with TomTom CityMaps – the last ever version
available for EPOC devices dated 2001. I
bought all these things on eBay, the Palmtop versions cost me about £15 each
including postage, though you can sometimes get them cheaper now, while the
TomTom version I got for the bargain price of only £7 including postage –
probably because very few people are aware of its existence. All of this mapping software is great,
though I use Route the least.
Next Steps – Get Your Hardware
The next thing I bought was the Palmtop GPS receiver, again
on eBay. These are quite rare and I had
to wait a few weeks until one came up – it also cost me £65 (ouch) with Street
Planner Millennium but, compared to buying any other kind of GPS on the market
at the time, it’s still good value. I
was eager to try it out and hooked it up as soon as it arrived. It’s a bit of a tangle of wires and I still
haven’t yet forked out for an in-car holder for the 5mx, which is really needed
to use it in the car, otherwise the Psion ends up loose on the front seat! But it works well and the novelty of having
a moving map as I’m driving along still hasn’t worn off. It’s also interesting to see speed and check
on location and other geo data as well (when parked of course). Having said all that, I thought I’d bought a
dud receiver at first; I didn’t know anything about the time taken to log on to
the satellite data – the acquisition rate – which can be anything up to a
minute or more from cold, especially if only a few satellites are
“visible”. It took me some time to
appreciate what was going on and I made this fact worse for myself by trying
different settings, which effectively started the acquisition process from
scratch each time. Anyway, I eventually
got everything working and, whilst the Palmtop device can receive signals from
up to 12 satellites, not all are visible at any one time and 5-8 seems to be
fairly typical – a minimum of 4 is supposedly required for an accurate fix but
3 seems to work well enough.
Real World Use - and Moving on to The Next Stage
So I used this combination for a while but not for much more
than as a gimmick because, where I live (on a Scottish Island group), serious
route or street planning isn’t really an issue! And when I’m on the mainland, I tend to be without a car, so no
means to power the GPS. I started to
think how I could get round the power issue both for when I travel away from
home but also so that I could use the set up when on foot to help in some of my
other interests such as environmental data recording and in astronomy.
Power Mad
There were two main problems to get round; firstly, the
actual source of power and, secondly, how to supply it to the device. The receiver requires 0.9w at 5v dc but is
supplied via a car cigarette adapter that is plugged in to a 12v output. Obviously I didn’t want to remove the
adapter and fit another plug or connect the wires direct to independent
batteries because I wanted to retain the option of powering the device with car
battery power. Also, the adapter
converts the 12v car output to a 5v input to the device and I thought that
would be a useful fact because 5v is an odd voltage to be achieved with readily
available batteries. I simply didn’t
know how long I could expect the device to run whilst in handheld mode but
thought that two 6v lantern batteries should provide sufficient power – the
bigger the better, I thought because at that stage I was only taking account of
the voltage, not the actual power drain.
The next problem was surprisingly simple to resolve, namely
how to connect the cigarette adapter to the batteries. A quick trip to a local car spares shop
resulted in my purchasing a cigarette adapter socket into which I could plug
the adapter - at the other end it had crocodile clips. Initially I used the crocodile clips to
attach the socket to the batteries but later removed the clips and attached the
bare wires direct to the terminals – I arranged the batteries in series to
achieve 12v. All worked fine first time
and I was rather pleased with my achievement - so I wandered off into the
garden and located myself – cool! But,
in the nature of these things or, more accurately, in my nature of never being
happy with what I’ve got and always looking for improvements, I decided to
change things. Strictly speaking there
was a very good reason to do so because the first version had one major problem;
two lantern batteries weigh in at well over a kilo (nearly 2½ pounds) and take
up quite a lot of space in a backpack that’s already full with lots of other
equipment.
| |
|
|
 |
One quick call to my
brother later (he’s a bit of an electrical whiz kid) and I was convinced that
8AA batteries would provide sufficient power output for the GPS device and he’d
also pointed me in the direction of the necessary battery holders. I got these from RS Components on the web (http://rswww.com/) and they are RS Stock no:
594-628 “Multiple holder for 4xAA short cell” at £0.25 each. Postage to where I live incurs a surcharge
so the total order of two holders cost me £6.40 delivered – not a huge outlay. I joined the terminals on the two holders
together with short lengths of inner copper wire from lighting cable and the
wires to the cigarette adapter socket are attached the same way – the AA
batteries are retained in the holders by springs that hold these wires secure. The pair of battery holders, the short
lengths of wire, the cigarette adapter socket and the 8 AA batteries are all
contained within a small zippered case that was originally intended to hold
spare batteries and compact flash cards but is ideal for this purpose and
weighs in at just 300g (10oz) – a vast improvement. Also the case fits in a pocket or has a belt loop attachment,
which is very convenient.
Real World Use – Take 2
So how is it in use?
Well, in a word, fantastic – if you’re into this kind of thing. It’s really great knowing exactly where you
are as you’re zipping along on a high-speed train or flying over some European
country (provided you’ve pre-loaded the appropriate maps of course). But on a more practical level its use is a
bit restricted by the fact that not only do you have a power pack connected to
a GPS receiver with one wire and back to the Psion with another wire, the Psion
has to be open and switched on for the GPS to work. This has two implications; firstly the Psion has to be in always
on mode, either using its own batteries or externally powered. To cope with this I have also acquired a car
cigarette power adapter splitter that provides two sockets and a Psion car
adapter. This and the GPS adapter are
both powered from the AA battery pack – more wires!
The second implication is simply that the Psion5 is
open. This means it is at risk from
being dropped or rained on, the screen may be difficult to see in bright
sunlight and it may simply be awkward to use it (especially with the pointer or
trying to use the keyboard) depending on what you are doing. For example, whilst walking or using any
other instrument, such as binoculars, camera etc or negotiating rough terrain
or climbing over walls it can be difficult.
So I tend to limit its use in these circumstances to when I’ve stopped,
either to accurately record the position of, say, a plant or landscape feature
or to use it to confirm my location at a place that I’m observing from (e.g.
for wildlife or astronomy). The photos
show me doing just that in Madrid recently.
 
Conclusion
Am I likely to use it?
Yes – it’s already proved useful on a couple of trips and, whilst a bit
fiddly it does what I want. Yes I could
do some of these things with a Garmin device and could buy SatNav for the car
but that would be the easy way – and also cost considerably more than I’ve
already spent. But the only other
single device that could do what I’ve managed to achieve would be another PDA
platform and, frankly, having tried a variety of devices from the other
platforms, none come close to being a stand-alone GPS, mapping, database, word
processing, internet-enabled device that also just happens to have all my
contacts, agenda, instant note-taker, voice recorder, newsreader and many
others on a device that I can type and directly exchange files with my phone,
my laptop and other devices without wires or conversion. A Pocket PC with a compact flash GPS
receiver would certainly be neater but there’s no way that its battery would
last all day in the field so perhaps that’s the real gimmick?
Shopping List
Psion 5mx (I already had this)
Decent size Compact Flash card (this too - I use 128MB)
TomTom CityMaps Europe (£7 eBay)
Palmtop Route Planner Europe Millennium (£15 eBay)
Palmtop GPS receiver (£65 eBay)
12v Power source (8 AA batteries and battery holders £6.40),
connected to…
…Cigarette lighter socket (£2.99)
In-car power supply for 5mx (£6.99 eBay)
Double cigarette lighter adapter (£3.50)
Plus 8 AA batteries, say £1.99, but I already
had them too!
Case to carry the battery holders, batteries and cigarette
lighter socket (I already had a suitable case but a small plastic food
container would also suffice)
Total outlay £106.88 plus lots of thinking time and a few
hours to obtain, assemble and try out all the bits and pieces – time well
spent.
N.B. eBay prices are what I actually paid including postage.
|
