In the newsletter of January 1990, I described a program called POLLTAX for a pocket computer produced by Psion plc (Bennett 1990). The same company subsequently introduced a new series of machines, Series 3, which are a substantial improvement in all respects. The current model, introduced in October 1996, is the Series 3c, but it represents only minor changes on the Series 3a, which has been available for some time. This note describes the basic features of the Series 3a, provides access to more information, and introduces three programs of mine that might be useful to readers of this newsletter.
The Psion Series 3a is a palmtop, or hand-held, computer, weighing only 275g (including batteries) and measuring 165x85x22mm. It is available in four RAM sizes, 256kb, 512kb, 1Mb, and 2Mb, and has two slots for addition of extra memory, usable as RAM. Much the cheapest way to buy memory is buy it in the machine, so I shall discuss a 2Mb Series 3a for the rest of this note. The operating system is windows-like: a series of icons, with the active icon highlighted. The keyboard has a 57-key QWERTY-pattern, capable of generating 244 characters (including the IBM extended character set). Power comes from two AA batteries, with a life, so Psion say, of up to 80 hours, but I rarely get more than 50 hours. There is also a backup power supply in the form of a small camera-type battery, which supports the system if the regular batteries fail for any reason. An external power supply is also available, but I have not tried this.
The Series 3a comes with a number of applications pre-loaded. These include a Word-compatible word processor, a Lotus-compatible spreadsheet, a diary, a database, a calculator, and a clock/alarm system. Multiple application can be run simultaneously. A serial link can connect it to a PC or Mac to download files, and a modem plus terminal emulation software make it possible to connect to any dial-up service, including an internet provider. Psion have just announced a product called PsiMail Internet, which is compatible with a standard Internet account, and allows on-line browsing of the World Wide Web: (http://www.psion.com/productguide/scpsimailint.html). Two irritating deficiencies of my Series 3a are the rather clumsy means of seeing the directory structure (now much improved in the Series 3c), and the lack of a backlight (remedied in US models of the Series 3c, much to the irritation of UK Psion users). This machine is therefore a fully functioning computer, capable of most of the things one would expect from a computer, including connection to another computer for the things it cannot do.
For scientific purposes, as with the old Organizer II, the key feature is a programming language, called OPL. This has been upgraded to handle the new windowing environment. Apart from the inbuilt application, there is a vast array of software available for the Series 3a, much of it free- or shareware. One that I find especially useful is a scientific calculator Calc 3a v 1.6 by Richard Schmidt (http://home.worldonline.nl/~rschmidt/). A good way to get a flavour of the quantity and quality of this software is to take a look at Steve Litchfield's WWW site, and especially his reviews of Psion software: (http://ourworld.compuserve.com/homepages/slitchfield/).
I have written or modified three programs that may be of interest to palaeoecological users of the Series 3a or 3c.
POLLTAX3
I have converted and extended my pollen-counting program, POLLTAX, into a system that runs on the Series 3a, renaming it POLLTAX3. It should also work on the Series 3c, but I have not tried it (yet). This program works similarly to the original, but differs in the following respects:
LLTOGR
This package consists of four utility programs and a driver module for the Psion 3a/3c to make conversions from latitude and longitude to National Grid co-ordinates for Great Britain and Ireland. They are not finely polished programs, but working utilities that do a job as simply and as quickly as possible.
Conversion from longitude and latitude is by exact calculation using formulae and constants from the publications of the Ordnance Surveys of the two areas. The reverse calculation is by successive approximation (make a guess, see how close it is, make a better guess, etc), and thus takes longer. I have tried to minimize this time by rearranging the equations, but there a number of trigonometrical calculations that seem to be unavoidable. Output has been tested against examples given by the Ordnance Surveys and against values from maps.
The programs are available by anonymous ftp to ftp-palecol.plantsci.cam.ac.uk, in directory pub/psion/lltogr. There is a zipped package of the five executables, together with additional details about the program (lltogr.zip). The details are available separately as a file called README.
PSGPS
This is a program for connecting the Psion Series 3a/3c to a Magellan GPS and analysing the data. Steve Litchfield's WWW site: (http://ourworld.compuserve.com/homepages/slitchfield/) provides details of how to connect several other GPS systems to the Psion 3a/3c. The heart of PSGPS is built around Lou Maher's GPS.BAS (Maher 1994), converted to OPL, but then extended to take advantage of some of the Psion's features. The program works either by receiving data (NMEA 0183B format) from the GPS, and plotting it (so you can follow a route), or by analysing data previously collected, as described by Lou Maher. The Magellan XL is very handy to use in the field, and works comfortably within a car, preferably tucked above the dashboard, giving a clear view of the sky through the windscreen.
This seems to work well on most cars (I have tested it in a Fiat Panda, Vauxhall Astra, and Trabant), and at speeds of up to 140km per hour (in Germany, but not in the Trabant). The Magellan has an output lead that can be connected to the Psion's serial lead, and once both machines are up and running, the Psion display plots the data received, at a scale chosen by the user. The advantage of doing this is that the Psion display is much better than the GPS provides, and is more flexible (because it is programmable). I have included a set of databases (Psion .dbf format) of the latitudes and longitudes of the main cities in all continents: the locations of these can be indicated, as can marks at any point chosen by the user while the program is running or from a personal database. The utility of such a system for basic route-finding or following on the open road or in cities has to be seen to be believed. One day, all vehicles will have something like this built in. The system can, of course, also be used in a static location to show the spread of points received by the GPS (as Lou illustrated). For users in the UK or Ireland, the output display figures can be in their National Grid units instead of Latitude and Longitude.
The program and associated databases are available by anonymous ftp to ftp-palecol.plantsci.cam.ac.uk, in directory pub/psion/psgps. There is a zipped package of the executable, together with additional details about the program and databases (psgps.zip).
Further details of the Psion Series 3a and Psion Series 3c are available from Psion plc: (UK URL: http://www.psion.com/, US URL: http://www.psioninc.com/). I have set up a WWW page with details of other sources of information, including suppliers, newsgroups, and software: see http://www-palecol.plantsci.cam.ac.uk/psion.html.
References.
Bennett, K. D. 1990. Pollen Counting on a Pocket Computer. INQUA Working Group on Data-Handling Methods, Newsletter 3, 5.
Maher, L. J. 1994. Using the Global Positioning System. INQUA Working Group on Data-Handling Methods, Newsletter 11, 23-28.