Real time interactive circuit simulation software,
can any body recomend free or reasonably priced (cheap) software,

That's a big topic. But if you want to simulate analog circuits then I recommend LTSpice IV from Linear Technology available for free.

Thanks Paul
But I want to design a oneshot controlling anastable oscillator to control the indicators no my MK using push buttons with a variable time out, using a LM556 timer . Digital I belive.

This thread any good? http://www.locostbuilders.co.uk/viewthread.php?tid=155057
This?

How about using a pair of "Universal Timer" kits from Maplin?

The timer output can be adjusted from under a minute or up to 15. However, by changing some of the analogue components in the kit this window can be very easily adjusted. You would still need a flasher relay but the timer kit would allow one shot to close a relay for pre-set time.

I have one of these for a similar (non-indicator) application and must say it is very simple to make and use.

Have a lok at Maplin item number VF06G

Richard

ETA: Reading the thread linked to above I notice a question about both being able to be on at once. As the maplin kit has buttons for on and then off (stops the timer counting down and opens the relay) the two kits could be linked together to turn each other off, either mid count down or at any other time...

By the, yes I do realise I haven't answered the orinignal quetion inthe slightest!


Have a look at Yenka. It used to be called crocidile clips and is quite good for simulating analgue and simple digital circuits. You can get a free home licence. It has a time of day based licence that stops you using it during school hours (its a pupil at home licence) but that is run off the windows clock time anyway, socan be "adjusted" ;-)

[Edited on 27/1/12 by jamesbond007ltk]

[Edited on 27/1/12 by jamesbond007ltk]

Hello,
I have just been in the garden pruning some bush thing so haven't replied sooner. LTSpiceIV does have a model for a 555 timer. The LM556 is just a dual 555 but the software will take a bit of a effort to learn however and it's probably not worth the effort for a single project.

Thanks all for your prompt replies,

I have just downloaded Yenka (thanks 007) and it looks as if it will do just fine after I have had play to find out how it all works.