Using Virtual Wiring In An Age Of Instant Solutions


by Marc Jarchow - Date: 2007-04-18 - Word Count: 436 Share This!

The subject of this article is virtual wiring or wires. So what do I mean by virtual? Usually if one wants to connect a digital signal to a relay then one has a circuit which drives the coil, this pulls in the relay contacts and this creates an isolated switch which may be used to provide power to a light or other suitably rated appliance. If the distance between the initiating signal and the appliance is great then one has a choice of either extending the digital signal with a long piece of wire or extending the switch side with long wiring. This seems to be a simple solution but in many cases, extending the wiring may not be the answer if the extension is complex, not aesthetically pleasing or many wires are involved.

The solution is virtual wiring and this can be implemented in a number of different ways.

1) If some wiring already exists then by virtue of multiplexing (combining many signals into one compound signal) and demultiplexing (taking one compound signal and expanding it again into many) electronics on either side, existing wiring can be used if an increase in the number of switches is required without laying extra cable.

2) The mux/demux solution can also be implemented with the use of fiber optics, where the compound signal is transported by means of modulated light.

3) Another transport medium is rf (radio frequency) In this age of Zigbee and other wireless standards, the compound signal can be transmitted through the air without any visible means. The simplest implementation would be a switch (or eight or more) on the near side being closed, detected by the monitoring electronics, assembled into some kind of protocol, transmitted wirelessly, received by the far unit, disassembled and the relevant relay or other switch mechanism would then be toggled. This would allow lights, appliances and other devices to be controlled without the addition of any control wiring.

The natural extension of this type of virtual wiring is to extend analogue signals as well. An example of this could be an appliance/device that needs to be set at a particular value. This value could be read (using a A/D converter) at the near side, assembled and transmitted as described previously and then output to the device in question as an analogue signal (using a D/A converter).

The one drawback of this type of signal extension method is that there will invariably be a delay between switch pushed/signal read and the corresponding action on the far side. Usually however a small delay is acceptable and other high speed methods exist for signals that require a higher bandwidth.


Related Tags: communications, virtual, wiring, zigbee, rf, radio frequency, multiplex, demultiplex

Marc Jarchow 46 year old entrepeneur providing MODular ElecTRONics solutions for the Professional (custom instruments for your business), Educator (can be used as a training aid), Entrepeneur (can be packaged with your logo) and Hobbyist (make your own home based products) using low cost modules to create whatever application you have in mind.This is all done via modetron.com

Your Article Search Directory : Find in Articles

© The article above is copyrighted by it's author. You're allowed to distribute this work according to the Creative Commons Attribution-NoDerivs license.
 

Recent articles in this category:



Most viewed articles in this category: