OVER 2 YOU, 128 (29/04/03)

VIRTUAL MACHINES

Can anyone suggest a simple software package for modelling mechanical components and virtual machines for educational purposes?   Something that would allow you to drag, drop, re-size and combine graphical representations of cogs, gears, levers and cams, and then allow you to run the virtual machine would be ideal.   Some years ago I came across a game called "Incredible Machines" that allowed you to do something similar, but maybe something better has been published since?
Ian Lower, via email

Have a look at "Crocodile Clips" products. Information and downloadable demos can be found at: www.crocodile-clips.com.

Nick H

I recently came across a new version of Incredible Machines in my local Game store, selling for only £9.99. It’s called ‘Even More Contraptions’ and like Incredible Machines is published by Sierra (www.sierra-online.co.uk). It is very similar to the earlier program but with many more puzzles and components, so you can design your own virtual machines. Great fun, I can’t recommend it highly enough; it has kept my 12-year old son and me amused for many hours.

Mike Collier, via email

EXCEL MORTGAGE

I believe there are functions within Microsoft Excel that deal with various mortgage calculations. Can anyone tell me the correct one to use for calculating how much is left outstanding after a certain period?
P. Mylam, via email

I cannot find any financial function in Excel to calculate mortgages however one can calculate the balance remaining in a mortgage by using the following formula:
S=(P-a/r)(1+r)^n+a/r 

where 'S' is the remaining balance, 'P' is the amount borrowed; 'a' is the monthly payment; 'r' is the interest rate per month i.e. APR/12 and 'n' is the no of monthly payments.
Ram Ranganathan

I designed a very simple spreadsheet program sometime ago, which does the calculation that P. Mylam is looking for. It assumes interest is calculated on an “annual rest” basis. If lesser intervals (monthly rests etc) were to be involved, it would require some revision.

To calculate monthly repayments, I have typed labels in cells B1 Capital, B2 Interest rate, B3 Repayment term, B4 Monthly payment to repay loan after given term. In cells A1 to A3, the relevant numerical data are inserted, e.g. 10,000 in A1, 5.00 in A2 and 20 in A3. Cell A4 contains the formula that gives the monthly payment and is as follows:

=ROUND(((1+A2/100)^A3)*(A2/100)/

((1+A2/100)^a3-1)*A1/12,2)

To calculate the debt after a given period of time, type labels in B6 Capital / current debt, B7 Interest rate, B8 Monthly repayment, B9 Repayment term, B10 Debt at end of repayment term. In cells A6 onwards, insert the relevant data, e.g. 10000 in A6, 5.00 in A7, 66.87 in A8 and 14 (say) in A9. The formula for cell A10 (which will give the debt after 14 years) is:

=A6*((1+A7/100)^A9)-((1+A7/100)^A7-1)/

(A7/100)*A8*12

The variable data can then be changed to suit any circumstances. If cell A10 ends up with a negative value, the mark has been overshot. Simply change cell A9 to appropriately lower terms until the desired result is achieved. If in this example, it were desired to find out after how many years the debt would reduce to, say, £5000,just alter cell A9 by trial and error until a result is achieved. Alternatively, click Tools then Goal Seek. In the window that appears, set cell A10 to 5000 by changing cell A9. Press OK and you get the exact length of time.

Derek Barnes

SELF SUFFICIENCY

I am a big fan of the seventies sitcom The Good Life and whilst I don’t aspire to full self-sufficiency, I wouldn’t mind having a go at generating at least enough electricity to run my PC and a few lights, from renewable or sustainable sources. Aside from covering my roof with solar panels, are there any more practical methods a reasonably competent DIYer could tackle? 

Bill Clements, via email

Homepower Magazine (www.homepower.com) is a good starting point. Being American the circuits given are 120 volts, but can be modified.

Peter Whitworth

Your correspondent should pay a visit to the Centre for Alternative Technology (CAT) near Machynlleth in North Wales. CAT is just brimming with ideas for would be ‘Good-Lifers’, including lots of demonstrations of alternative energy products and one of the best-stocked bookshops I have ever seen. They also have an excellent restaurant on the site and I can personally recommend the homemade vegetable soups and curries! The place is staffed by people who have a genuine knowledge and passion for alternative technologies and it makes a great day out for all the family. They also have an informative web site, which you can find at: http://www.cat.org.uk/

Graham Ferguson, Bournemouth, Dorset

MINDREADER

My brother recently emailed me details of a website (www.cyberglass.biz/FlashEx/mindreader.html) that claims to be able to ‘read your mind’. Unbelievably it actually seems to work but I can’t for the life of me see how it does it; can anyone put me out of my misery?

Trish Naylor, via email

Following on from your solution to the Mind Reader web site here’s a variant on the same theme. Tell someone to think of a number and multiply it by 9 Keep adding the result until you get a single figure i.e. (13 x 9 =117 1+1+7 =9). Subtract 5 from this number. Using 1 for A, 2 for B etc think of a country beginning with that letter. Take the second letter of that country and think of an animal beginning with that letter. Tell them they thought of an Elephant! Obviously it is always 9 therefore the letter is D nearly everyone thinks of Denmark. How many others can you think of? Therefore the animal is nearly always E and most people plump for the Elephant, (except the odd smart Alec with Emu…).
Wally Wallsworth

SEEING THE TREES

I have to undertake a project, which involves going round a 40-acre site and recording the name, age and position of all of the trees. What I have in mind is some sort of hand held GPS system that permits "waypoint" logging with a reference code and then having recorded all of the trees (about 1500 I think) I then need to "download" or transfer the data to a suitable piece of software which will take the data and permit full display, editing and printing.
Can anyone help fill in the details?
Ric Ackland-Snow, via email

I have devised and manage a system that records details and location of some 5,500 plants and trees in a 140-acre garden. It comprises a database, in Access, and a set of maps in AutoCAD format with the tree locations and reference numbers being transferred by means of script files from the database to the maps. The main problem is surveying the garden and its trees. Unfortunately GPS systems are difficult to find which are accurate to about a metre and also reasonably cheap and will work under trees. If Ric Ackland-Snow cares to get in touch I shall be glad to help.

Michael Bennison

SKETCH SOFTWARE

I recently came across a photo-booth type machine that took your picture and then turned it into a surprisingly authentic-looking pencil sketch, with a hand on the screen ‘drawing’ the picture. Does anyone know of a PC program that can do something similar?

Lew Fraser, via email

Serif PhotoPlus can be used to create a sketched look; there is an 'Ask the Expert' article at: http://www.serif.com/community/articles/20020416.asp
explaining how to do it. Version 8 is the current one but versions 6 and 7 also have the necessary features; although still available from Serif, PhotoPlus 6 is cheaper from Amazon – see http://www.amazon.co.uk/exec/obidos/

ASIN/B00004YRS3/202-4480781-5178268
Alfred P., via email

TWO INTO ONE

I work from home and have for some time rented two BT lines. One for incoming voice calls; the other for Internet and a dedicated fax machine. I would like to reduce to just one line, whilst retaining the discrete fax (rather than switching to a computer-based fax function). I tried a 'fax switch' some years ago but it proved useless. Does anyone have any suggestions as to how I can successfully manage phone, fax and answering functions on a single line?
Robin Wager, via email

I have successfully used HP OfficeJet multifunction machines, together with an answering machine, on one line, for some years.  I currently have an OfficeJet K80, which combines printing, faxing, scanning and copying in one unit the size of a fax machine.  When the phone rings, the OfficeJet listens and if it recognises a fax tone then it automatically answers and prints out the fax.  It can cope with an answering machine on the same line and no computer is required.  I think the K80 costs about £200.

Roger Bullock

CAN YOU HELP?

Can anyone recommend child-friendly "fun" software to teach my two young children aged 6 and 8 to touch type? Considering nearly all their work in future (at school, college and for the rest of their lives) will be done via keyboards, it dismays me to see them stooped over their desks, pecking and prodding away. If we don't nip it in the bud soon, they will develop a very poor technique.  I learned to touch-type aged 19, and have found it immensely helpful ever since. It would be useful if the learning came in the form of a game of some kind.

Neal Philo, St Annes, Lancashire.

Recently I bought a Nimslo 3D camera at a local charity shop. I have been unable to find out anything about it at the library and the sales assistant in a well-known camera shop said he had never seen one of them before. Does anyone know anything about it? Can you still get films and have them developed? It doesn’t look very old and appears to be in good working order and I would dearly like to try it out.

James Ackerman, via email

It always seems to be ‘such-and-such week’. Is there a central coordinating body for these events, if so how and where can I get in contact?  The Internet seems like the place for it to be, but I can’t think of what to search for. I want to organise a ‘week’ for the organisation I work for and naturally I don’t want to clash with anyone else’s.

David Hillier, via email