Schematic on powerline communication

[hdaroga]

hi guys hope u might have heard about powerline communication.
By this method electronic devices can be controlled using the mains power supply.
if we transmit the data on a frequency, other than the powerline frequency the data can be transmitted unaffected. this is an upcoming thing in modren electronics.
if any 1 had a schematic on powerline communication using OFDMA (orthogonal frequency division multiple access) technique could post it here.
anything related will do plzzzz.

 

[Nigel Goodwin]

hi guys hope u might have heard about powerline communication.
By this method electronic devices can be controlled using the mains power supply.
if we transmit the data on a frequency, other than the powerline frequency the data can be transmitted unaffected. this is an upcoming thing in modren electronics.

Actually it's not very 'upcoming', it was fairly commonplace back in the 1970's - mostly it's faded away now.

 

[gladian]

Why has it faded away?
It seems like a really good solution except when the mains fails I suppose all comms are lost?
I was hoping to have a play with this do you know how it's done and can you provide an example circuit please?

 

[philba]

google for x10, to start with.

 

[HarveyH42]

Ever hear of the X-10 line of home automation products? It's been around for a very long time. I help a neighbor install some crappy security cameras once, which ripped out a month later, and paid a proffesional to install some overpriced video system. The on/off functions were through the outlet, while video was still the basic wireless. Really filled up the outlets, must have had a dozen wallwarts going, monitor, VCR...
Anyway search for "X-10", the company site will tell a little about how it works, but not enough to get you to build your own. You should get thousand of hits, relating to home built devices and a deeper explaination of how it works, and how to do it yourself. Might even find the sort of device you are looking for. You didn't really give any detail on what kind of comunication you were after, but guessing voice. There are devices which allow you add a telephone jack through your house wiring, but don't remember the company. As far as going outside your property... don't recall seeing anything like that, would think your signally would quickly pick up a lot of noise, or get filtered out.

 

[bigkim100]

Up and coming.....!???!!!??

Up and coming technology.....!???!!!??..... man, I remember Popular electronics offering schematics in the 70's for these 120 volt line modems.
Trek down to Home depot into the electrical department and you will find units that are plugged into a 120 volt outlet, Then any phone or modem can be plugged into them to communicate between the units, over the 120 volt line. They are made by RCA.
Ive got another hot tip on another up and coming technology.....I hear that COLOR TV is soon on the horizon to be available in everyones home!

 

[Papabravo]

The alleged up and coming technology might be BPL, or Broadband over Power Line. On the basis of its potential to cause interference to licensed services and the technological problems I think its acceptance by the market place is an open question. This is especially true if it is not price and bandwidth competitive with cable and DSL.

The power line is a low impeadance, unshielded, and generally very crappy way to move information. Isolation transfomers wich occur in the power distribution system effectively limit the available bandwidth to a very low value. The signal level at a receiver in the vicinity of BPL lines is often 20 dB over S9. This effectively blocks any other signal across a broad band of frequencies. Power lines radiate like crazy, so it takes large amounts of power to get acceptable signal to noise ratio over any appreciable distance. The infrastructure rollout costs have utility investors and wall street types casting a jaundiced eye in the direction of BPL.

In general there are many better ways to move data than over power lines. It's probably not worth the trouble to learn.

 

[RadioRon]

The alleged up and coming technology might be BPL, or Broadband over Power Line. On the basis of its potential to cause interference to licensed services and the technological problems I think its acceptance by the market place is an open question. This is especially true if it is not price and bandwidth competitive with cable and DSL.

The power line is a low impeadance, unshielded, and generally very crappy way to move information. Isolation transfomers wich occur in the power distribution system effectively limit the available bandwidth to a very low value. The signal level at a receiver in the vicinity of BPL lines is often 20 dB over S9. This effectively blocks any other signal across a broad band of frequencies. Power lines radiate like crazy, so it takes large amounts of power to get acceptable signal to noise ratio over any appreciable distance. The infrastructure rollout costs have utility investors and wall street types casting a jaundiced eye in the direction of BPL.

In general there are many better ways to move data than over power lines. It's probably not worth the trouble to learn.

Good post. BPL is, for those outside the industry, apparently "up and coming" but as Papabravo says, those on the front lines are just now (that is, over the last one or two years) learning that this is a bad idea for the reasons he cites.

 

[mshemyalnisar]

well this thing is queit new in our part of the world.

as for the subject i have heard it increases the impedence of power lines quiet drastically.

 

[RODALCO]

I work in the powerindustry, distribution side.

There is already a lot of noise created on the mains which are switching spikes from high voltage switching, tapchangers in substations, fridge motors, etc.

Then we have the switchmode powersupplies, in computers, vcr's, tv's, etc,
which superimpose a lot of square waves on the mains.

Then there are ripple signals from the powercompany through the mains, to control hotwater and streetlighting.

Why would you want to use it for communications ?

As already said by the other members, there are a lot better options available.

The older type babyphones used to work through the mains, as long you are on the same phase as your neighbours you got away with a audio signal to monitor a child or so, but the quality was very poor.
These were ok in the 70 and 80's prior to the advent of the SMPS.

 

[Papabravo]

well this thing is queit new in our part of the world.

as for the subject i have heard it increases the impedence of power lines quiet drastically.

This is some brand new physics! I would argue that it is impossible to change the impedance of a transmission line by putting a signal on it.

It is probable that a significant amount of hardware per mile..er kilometer..is required to allow brodband signals to propagete. I presume this hardware has an affect on the impedance of the power lines.

 

[William At MyBlueRoom]

Here's one for the 16F877 with schematic for X10 from microchips site

**broken link removed**

 

[Papabravo]

X-10 the baudrate wonder. Do you think it's a threat in the MP3 download arena? How about video on demand? Interactive gaming maybe?

 

[audioguru]

well this thing is queit new in our part of the world.

For most of us it is an old reminder of the problems with our past.
Don't you have electronics websites in your part of the world?

 

[afraym]

pleas

i want to see the circut digram of power line communication

 

[ericgibbs]

i want to see the circut digram of power line communication

hi,
This thread is 2 years old.

 

[audioguru]

hi,
This thread is 2 years old.

The idea is 30 years old in our part of the world and is "quite new" in another part of the world.