my first symbian application

and also my first Python script.


PyS60 is cool. You can create a script and run it on your Nokia. Simple. Then I learnt that there are tools like ensymble (from google code) to create a sis file to install and distribute the application.

I wanted a quick and simple unit converter. Although SI units are used by almost all countries in this world there are still people who use the awkward system of feet, psi, ounces etc. Thanks to the French and their metric system, the SI units are more readable and more easy to understand. I wrote this script for my Nokia to convert from various units. I also included old Maltese system of measurements.

To run on your nokia, just install PyS60 to your nokia - from https://garage.maemo.org/frs/?group_id=854&release_id=3264 - and copy the script to your memory card. I use Linx and obex to copy th files using bluetooth: which is much more handy.

import appuifw

convCat = [u"Length", u"Area", u"Volume", u"Weight", u"Temperature", u"Pressure"]


cont = 1
while cont:
 # reset convCat
 convUnits = []
 convCalcToEsp = []
 # get Category
 convCatIndex = appuifw.popup_menu(convCat, u"Select a category")
 if convCatIndex == 0:
  # length, use m as 'Esperanto'.
  convUnits = [    u"thou (th)", u"inches (in)", u"feet (ft)", u"yards (yd)", u"miles (mi)", u"knots (kt)", u"mm", u"cm", u"m", u"km", u"qasba", u"rod", u"fathom", u"league"]
  convCalcToEsp = [0.0000254,    0.0254,         0.3048,       0.9144,        1609,          1852,          0.001, 0.01,  1,    1000,  2.096,    5.0292, 1.853184,  4828.032]
 elif convCatIndex == 1:
  # Area, use m2 as 'Esperanto'
  convUnits = [    u"sq in", u"sq ft", u"sq yd", u"sq miles", u"sq knots", u"mm\u00B2", u"cm\u00B2", u"m\u00B2", u"km\u00B2", u"hectares", u"acres", u"tumoli", u"qasba kwadra"]
  convCalcToEsp = [0.000645, 0.092903, 0.836127, 2589988,     3429904,     0.000001,    0.0001,      1,          1000000,     10000,       4046.87,  1124.13,   4.391]
 elif convCatIndex == 2:
  # Volume, use m3 as 'Esperanto'
  convUnits = [     u"cu in",    u"cu ft",    u"cu yd",    u"UK gal", u"UK quart", u"UK pint", u"fl oz",     u"US gal", u"US quart", u"US pint", u"mm\u00B3", u"cm\u00B3", u"m\u00B3", u"litre (l)", u"centilitre (cl)", u"millilitre (ml)", u"cup",      u"tablespoon", u"teaspoon", u"Oil barrel"]
  convCalcToEsp = [ 0.000016387, 0.028316847, 0.764554858, 0.0045461, 0.0011365,   0.0005682,  2.841306E-05, 0.0037856, 0.0009464,   0.0004732,  0.000000001, 0.000001,    1,          0.001,        0.00001,            0.000001,           0.000236588, 0.000014784,   0.000004929, 0.15898      ]
 elif convCatIndex == 3:
  # Weight, use kg as 'Esperanto'
  convUnits = [     u"grain (gr)", u"drachm (drc)", u"ounce (oz)", u"pound (lb)", u"stone (st)", u"UK hundredweight (cwt)", u"ton",    u"mg",    u"g",  u"kg", u"tonne", u"ratal", u"wizna", u"qantar"]
  convCalcToEsp = [ 0.00006579891, 0.001771845,     0.028349523,   0.45359237,    6.350293,      50.802345,                 1016.0469, 0.000001, 0.001, 1,     1000,     0.7938,   3.969,    79.38]
 elif convCatIndex == 4:
  # Temperature, use C as 'Esperanto'
  convUnits = [     u"F", u"C", u"K"]
  convCalcToEsp = [ 1, 1, 1]
 elif convCatIndex == 5:
  # Pressure, Pa as 'Esperanto'
  convUnits = [     u"psi", u"bar", u"Pascal (N/m\u00B2)"]
  convCalcToEsp = [ 6894,   100000, 1]
  
 else:
  # 'back was pressed
  cont=0
 
 # check if there's a valid category
 if len(convUnits) > 0 :
  # check that if I made a programming mistake in arrays.
  if len(convUnits) == len(convCalcToEsp):
   # ok, hence calc.
   convFromIndex = appuifw.popup_menu(convUnits, u"Convert from:")
   if convFromIndex >= 0 :
    convToIndex = appuifw.popup_menu(convUnits, u"Convert " + convUnits[convFromIndex] + " to:")
   if (convFromIndex >=0) and (convToIndex >=0):
    conVal = appuifw.query(u"Convert " + convUnits[convFromIndex] + " to " + convUnits[convToIndex], "float")
    if convCatIndex == 4:
     if (convFromIndex != convToIndex):
      if (convFromIndex == 0):
       # convert from F to C or K
       resVal = (conVal -32) * 5/9
       if (convToIndex == 2):
        # convert C to K
        resVal = resVal + 273.15
      elif (convToIndex == 0):
       # convert to F
       C = conVal
       if (convFromIndex == 2):
        # convert K to C first
        C = C - 273.15
       # convert C to F
       resVal = (C * 9/5) + 32
      # now F is not select, hence conv from C to K or vice versa
      else:
       if convFromIndex == 1:
        resVal = conVal + 273.15
       else:
        resVal = conVal - 273.15
     else:
      # no conversion required.
      resVal=conVal
    else:
     # if not temperature, then use the following equation.
     # appuifw.note(u"calc: "+ str(conVal) + " x " + str(convCalcToEsp[convFromIndex]) + " / " + str(convCalcToEsp[convToIndex]), "info")
     # dummy = appuifw.query(u"calc: "+ str(conVal) + " x " + str(convCalcToEsp[convFromIndex]) + " / " + str(convCalcToEsp[convToIndex]), "query")
     resVal = conVal * convCalcToEsp[convFromIndex] / convCalcToEsp[convToIndex]
    # output
    cont = appuifw.query(u" " + str(conVal) + " " + convUnits[convFromIndex] + " = " + str(resVal) + " " + convUnits[convToIndex] + "\n\nConvert another?", "query") 
  else: 
   appuifw.note(u"Internal error (" + str(len(convUnits)) + "/" + str(len(convCalcToEsp)) + ")", "error")

Here's the script - then a sis may follow!

green energy, how?

We need power, power is not just energy, but it is like a concentrated form of energy. We consume energy in bursts and lot of it in such a small time. That is why we live in the petroleum era and which shall eventually decay and leave space to a new era.
A study says that if 1% of the Sahara were transformed into a solar farm, then we should solve our present need for energy.
But we need to harness energy so as to consume it in bursts far away from where it is generated. Transporting energy in its electrical form proved to be efficient and so far the only method which we know. Storing energy in its electrical form may not really prove efficient or possible on a large scale. Though once, I suggested to store energy in batteries scattered in distribution points round the island. These batteries are charged when we produce extra energy and then discharge during peak energy consumption.
Now I had this idea. We have sea, lots of it an very little land. Sun farming is possible but truly limited because of space, so why not use the sea surface? So I thought... what if we have a closed eco-water cycle? Water from the sea evaporates by using the sun's energy and then it condenses at an altitude. Water is stored (accumulator) at a higher altitude in a reservoir - something similar to a dam. Water from the reservoir will then drive a turbine and transform the potential energy in kinetic and eventually electric.

here's a diagram

               /----------------------|
              /                       |
  sun >      /             vapour     |
            /    \      condenses     | 
  sun >    /      \ ==================| 
          /        \ =================|
  sun >  /          \ === reservoir ==|
        /            \ ===============|
       /   green      \ ==============|
      /    house       \---------- --/|
     /     effect                | |  |
    /    evaporation             |X|  | turbine
   /                             | |  |
  /================ water=============|
 /====================================|

The scale involved is not on the small side but works very well in nature and should be tuned to work efficiently in a closed system. The trick is how to effectively condensate the vapour. The top of the structure may be covered in PV panels while the south facing side should all be in glass and well insulated. The area below the sun exposed area must cover an area much larger than that of the reservoir.