Petrol

										 From Lemon Technology
										(c) Graeme Bishko 1993

Shareware

This program is shareware. You can use it, distribute it (in an
unaltered form) and generally have fun with it. I accept no
responsibility for any loss etc. It took a fair bit of effort to
write it so if you feel you would like to pay something for it
(say œ5.00 ?) you are welcome to. At any rate, I would appreciate
any comments you may have about it or just something to tell me
you are using it. If you want to get in touch with me you can
E-mail me at:
	G.B.Bishko@sheffield.ac.uk
Snail mail:
	G.Bishko,
	Flat 5, 9 Whitworth Rd. 
	Sheffield
	ENGLAND 
	S10 3HD

Introduction

This application represents my first foray into Psion 3 software.
The basic goal was a rudimentary way of tracking petrol
consumption.  As usual it got a little out of hand. The program
works on the assumption that each time you put petrol in your
car, you fill it to the brim and record the number of miles
travelled since the last fill up. If you don't do this, you can
keep track of intermediate top-ups by noting the litres put in.

The program expects litres as the unit of petrol volume: all the
pumps in Britain seem to have gone metric. It still gives petrol
consumption in miles per gallon as I can't get used to litres per
100 k.m. If I get enough demand from the 'States, I'll do a
version for U.S. gallons, as long as someone tells me the
conversion rate!

The program presents a scrolling list of "fill-ups" and allows
choices to be made from a menu. There are the usual options for
adding and editing entries as well as a totalling function. Two
graphs can be drawn from the data: an histogram of MPG vs miles
and a line graph of miles per day vs days (this also shows MPG as
grey bars because the correlation is often quite good).

Installation Instructions

Petrol requires its own directory:
	\petrol
Petrol.opa will run from any drive but its load in module
(grpah.opo) and the icons will want to be in RAM. You may like to
have the application in a sub directory on FLASH with another sub
directory in RAM to hold these extra files. The four files needed
are:
	petrol.opa  Main application
	graph.opo Module to draw graphs
	pump.pic  Icon (should be in RAM)
	lemtec.pic  Icon (should be in RAM)

Instructions

On first use the program will create an empty file to use. You
can rename this if you want to, and the program can cope with
multiple files.

The next thing to do is to add a record to the database: Menu:
Edit/Add provides a dialogue for this to be done. You must enter
a number of miles, the number of litres  and the cost of the
transaction. A short note can also be saved.

Once this is done, a box comes up showing statistics for that
fill-up;  killing this box returns to the scrolling list.

The rest of the menu items should be self explanatory but I will
give some description of the two forms of graph.

Histogram

This graph shows the M.P.G. achieved in each fill-up block,
against the miles travelled. The width of each block is scaled by
miles travelled.

The initial dialog box allows you to choose which records to
graph and the y axis maximum and minimum. The y axis values are
set automatically. Should you change the records to be shown, the
y max & y min values will be rescaled and the dialog displayed
again.

The graph is initially drawn with labels on the axes. The will be
removed by the first key press whilst they can be re-shown by
pressing "L". The next key press returns to the main screen.

Line Graph

This shows M.P.D. (car usage) vs days. The vertical lines drawn
correspond to the first day of each month. The grey bars show the
M.P.G. achieved on each tank. The line is not really valid in
this case as each point is an average over the previous time
period.

The same dialog precedes this graph as the last. It should be
noted, however, that in order to calculate a value for miles per
day, the first entry in the list is passed over.