pc.controlled switch

Hello everyone.
from this question you may realise that I'm a Electro novice and the question I'm going to ask maybe a lot deeper that I realise.

I am looking for a low vlotage switch that can be controlled via my pc.
the switch would turn on and off a 9v device and would need to be no bigger than a match box.the switch could even have voltage regulater so that lower voltages could be used.

1application
I want to control a low voltage battery opperated lamp without all the wires and I would like to do this from my pc and when i'm away from home.
2 application
Lets imagine that I am a model train geek and the application i'm looking for would controll trains on the track via the pc.the voltage regulation would control the speed of the train.of course this is if I were a train geek. each train would have the control box that I am looking to contstuct with your help.

looking forward to your replys.Mark

If it's a model train you want to control DCC works very well.

https://www.cmlelectronics.co.uk/dcc/aboutdcc.htm

pc switch

Thanks Bill
You are half way there on that but I aslo want to develop the device I was enquireing about to turn on and off and also dim a low voltage light sorce,again via the pc.

Hope you can help more Mark

pc.switch

Hello!!
Avery nice man at wibotics gave me an address to look at a Transceiver that would be usable in the dvice I want to create.Could anyone help simplfy the usage of the Transceiver for me and also maybe give me advice on other components I would require.

Nordic Semiconductor wireless chip from Sparkfun.com.


ahttp://www.sparkfun.com/commerce/product_info.php?products_id=153#

Cheers Mark