Workshop comms

I'm with AndyF on this.

I have a Tomy baby alarm - two units, plugged into mains, one in living room one in workshop. One-way speech comms (SWMBO to me) and response is via a 'Click' transmit button - one for yes and two for no. The sound pickup is remarkable and means I can monitor for phone calls when she's out. Got mine on the Bay - good value!

Rgds

Bill

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Surely, No ...

If the connection is "Single Phase" then, by definition, everything on that connection is "on the same Phase". [and any local device that pushed any significant "out of phase" would be (a) stupid, and (b) illegal.]

The interesting question is; Why do the devices need to be on the same Ring ?

On a normal Consumer Unit, everything connects to the same pair of wires; so

1. why does it matter ?
2. does a Spur count as part of the Ring ?

Just curious.

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MichaelG.

I'd wondered about the point Michael raises as well. These things usually work by injecting their signal back into the mains wiring to be picked up by the other unit. So long as there is a connection they should work, and in a domestic situation, all on one phase, all circuits are connected together unless a fuse has blown or a breaker has tripped.

Mind you the information os from the same site that Stub had problems with over 6mm being the same as 1/4 inch so ................

Keith

The same ring bit might just be a precaution so they have an excuse if its a bit flaky...

Neil

If you look at the three reviews of this item, two say its rubbish, won't work even in same room, while the third says its wonderful; and the third is between house and garage, as Rik is looking for.

Even more confused now!!

The type I used to use is the two-way wired intercom type, as shown on the right of the link.

Phil

I dont have any problems my workshop is on the side of the kitchin

Mostly product data is aimed at the American market and the sellers just repeat it out without understanding a word.

How about one of those things old (american) shops used to have with a catenary wire and a little truck that whizzes along it. Or a 16mm railway track - that would save the wife having to come out with the coffee on rainy days. A little insulated tanker waggon and a converted cattle waggon for the biccies.

The "wireless intercoms" put a frequency modulated signal onto the mains. If you are on the same ring then there is a chance that you can hear the fm ( around 100-200KHz). It will also work on another ring from the same meter. However there are a lot of switchmode power supplies hanging on rings these days, they work around the same frequency, produce interfering signals and also have capacitors wired accross the L-N which will tend to greatly reduce the intercom signal.

So depending on what you have plugged in it may or may not work! A manufacturer or seller would be pushing their luck to say that it would always work.

The wired intercom will always work and no one else will find out how many cups of Tea or even Coffee you get through. Some DECT phones have an intercom which gives you a phone in the Workshop and a means of placing orders to the Catering Dept.

Billy.

All set today to go to Maplins and pick up one of their wireless intercom offerings as linked in my OP. I knew from what chaps on here had said that it was not certain that it would work. I sat musing earlier today wondering how I could ascertain - would they work or would they not? That is when I realised that I had what was needed to check it out before I shelled out on the Maplin kit. The solution? - homeplugs!

We have a printer connected to our router via a couple of homeplugs, I unplugged the printer homeplug, took it up the workshop and plugged it in then connected it to my laptop by ethernet cable. Result? - no result! In other words, the Maplin intercoms would not have worked.

The good news is, I have saved myself £30. The not so good news is that a wireless alternative to the Maplin type intercom does not seem to exist.

Thanks for all your suggestions but what wife really wants is a hands free voice activated system. I think she may have to dream on.

Rik

Rik

| "a hands free voice activated system."

How about an old style megaphone pointing out of the window towards the workshop then she could just shout loudly.................what's more you couldn't answer back!

Norman

Rik

It might be worth looking on the Maplin website for the small "Walkie Talkie" type radios about 30quid a pair. They are available from a lot of places apart from Maplins at all sorts of prices (often cheaper). They are battery units and are truely "wireless" as they are radios and you don't need a licence for them.

Keith

Who needs an intercom...............my wife just rings my mobile,or shouts down the garden.

Mark P

"Thanks for all your suggestions but what wife really wants is a hands free voice activated system. I think she may have to dream on."

Can be done; it's known as VOX or Voice operated transmission, where your voice (or any loudish noise) replaces the press-to-talk switch and switches on transmission. I have a handheld dictating machine with the equivalent; it records when you talk, though there is a moment's delay so it's best to say "Boo" to start record.

However, I don't think any of the cheap licence free PMR446 walkie talkies offer VOX, though some expensive ones do.

Andy

Rik

It might be worth looking on the Maplin website for the small "Walkie Talkie" type radios about 30quid a pair. They are available from a lot of places apart from Maplins at all sorts of prices (often cheaper). They are battery units and are truely "wireless" as they are radios and you don't need a licence for them.

Keith

She might learn some new words! tried that idea and the local kids had them as well!

Michael

An old mobile phone with a pay-as-you go card. Number pre-programmed into home phone.

If it rings - I don't answer it

If it's a short ring - then Tea/Coffee/Dinner will be served in 5 minutes - if it's a long ring then I need to get my butt inside sharpish!

IanT

Hi Rik,
I do not think the discussion about the two units of the intercom being on the same ring is relevant. All the sockets in your house are effectively connected in parallel even if they are on a different ring. There will be a very small amount of inductance between the live terminals of separate rings due to the trip coil in the MCB's (Or RCBO's) but this will have very little effect in the 100 - 200 Khz frequency range used by these intercoms. I think Billy Mills comments about noise from switch mode power supplies and the shunting effect on the intercom signals caused by the input filter capacitors on these power supplies is most relevant. The test using the "Homeplugs" is not relevant as these use different frequencies ( 4.5 - 21 Mhz) I obtained this information here. I think the only way would be to try the particular intercom. You would need to find a shop that would allow you to return them if they did not work for you. Is it not possible to use a wired intercom ? When I built my shed I dug a trench and put in a cable duct (40 mm waste pipe) At each end I made the transition from horizontal to vertical using two 135 Deg. bends rather than a single 90 Deg. bend. I threaded a length of string to pull in cables by passing it through a hole in the end of a 35 mm film container, putting this in one end of the pipe and connecting a vacuum cleaner to the other end. (Always leave a length of string in the pipe to pull in extra wires in the future.)

Les

Hi again Rik

Les says "You would need to find a shop that would allow you to return them if they did not work for you." and I seem to remember your quoting Maplin as the source of your intercom. I recently purchased a set top TV aerial from them to use when we relocated our TV whilst decorating. As the signal is a bit iffy here I discussed this with the shop assistant and he said " Well buy it and try it - if it doesn't work just bring it back and we will give you a refund " Have you asked your local Maplin store if you can buy one and return it if it doesn't work? In view of Les's comments above it must be worth a try.

Regards

Norman

Les, I was thinking of something similar to your 40 mm pipe, but use it in a similar way to the catenary wire(mentioned by Bazyle), propel a cassete with compressed air, this system is used in places like Hospitals for example, for sending samples to the lab etc. I can remember both systems being used up until the 1960s in department stores in Dunedin (NZ). One method whoosh, message gone, or received, second method clatter, zip, bang, message sent/received.

Theres always the old fashoned system my Grandfather had in his factory, long tubes, first you blow down the tube, and a whistle blows, person at other end removes the whistle, and the tube becomes a speaking tube, I'v know idea how effective it was, but Grandpa loved gadgets. Ian S C

Thanks for your info Les which I found helpful and enlightening. Based on your advice the Maplins visit is once again on the cards.

By the way Ian, it sounds like you are referring to Lamson tubes. In the 'fifties some of the shops in Bedford (UK) used these. I think that instead of using tills they put the customers purchase money in the container and it whizzed off to the cashiers office - change came back the same way. There was also another system that used a rail instead of a pneumatic tube. A sharp yank on a chain sent the money container hurtling along the rail to its unseen destination. Sheer magic for a small boy all those years ago.

I have seen one of these devices still in use today whilst on our travels but for the life of me (and her) we cannot remember where.

Rik

The tube system for money in shops and banks was very common and is still in use in some supermarkets.

Speaking tubes seemed to be standard on warships in films up until the fifties.

How about trained mice in your 40mm tube.