Author Topic: Sense what room you are in.  (Read 1708 times)

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Offline madsci1016Topic starter

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Sense what room you are in.
« on: October 13, 2009, 04:34:05 PM »
I am theorizing a uController powered "Super Remote" for my apartment.

Among other features, i want it to be able to sense what room it is in, so you can walk in a room and just hit the 'light' button, and the base station will send the appropriate X10 command to turn the light on in that room.

My current issues is how it senses what room it is in?

I was thinking some IR 'beacons' in each room that pulse out a different sequence, or flash at a different rate, and a IR receiver on the remote would see the beacons.

Has anyone tried something like this before? Do you think it will work?

Offline Soeren

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Re: Sense what room you are in.
« Reply #1 on: October 13, 2009, 06:05:10 PM »
Hi,

Yes, it has been done.
IR isn't a good idea for room identification, unless you carry your remote like a sword in front of you, enabling it to have a clear view to the transmitters, but a low power coded radio packet would reach it in your pocket.

Phonak, a hearing aid company makes a system like that for FM systems used (for hearing aids) in eg. schools for hearing impaired kids, so that when the students enter a room, their receivers are switched to the channel that the teacher use, instead of the class room next door where they might have taken a different class earlier that day. This is very expensive stuff though.

A better way would be to install an RFID reader in the remote and an RFID tag on each door frame (then you won't have to have a number of transmitters active all day).

The cheapest way to do it, like I did for a friend back in time, is using an IR remote and have a receiver mounted high up in every room (to be able to reach it from every corner of the room), all connected to a centrally placed controller that decodes the signal from the remote control, knowing from what room it emanated and then acting on the light, TV/HiFi, or whatever needs attention in that room.
It does need you to install yards and yards of wiring to be wireless that way  ::)  but you get a stable system that is very insensitive to (and not causing any) EMI.


However you wanna play it, Paper & Pencil used at the early stage can save you a lot of headache and money.
Regards,
Søren

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Offline madsci1016Topic starter

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Re: Sense what room you are in.
« Reply #2 on: October 13, 2009, 08:51:04 PM »
You are missing two important requirements, low cost and low installation impact.

I am still not convinced my idea won't work. Some moderate googling has revealed that not only have others done this, but there is actually a patent for this exact method of room identification; and some the high-er end Roombas can tell what rooms they are in by using infrared "lighthouses".

I already assume i will be pointing my 'remote' at a light to turn it off/on, like you point your tv remote at your TV. And i will code it to keep it's room identification remembered until it reads another room, meaning i will only need to point it at the light once until i change rooms.

Offline toepfer

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Re: Sense what room you are in.
« Reply #3 on: October 13, 2009, 09:14:43 PM »
I would approach it like this.
Your remote could have an ultrasonic send/receive function (you could prototype it with DTMF so you could follow it as it goes by ear) to a room id query receive/reply module in each room.
and an rf send(/receive (receive for confirmation)) to the base station.
When you hit a button on the  remote, any button, the remote sends an ultrasonic query for the room to id itself.
The room module replies with an ID code.
The remote then sends loudest reply ID code and the command button hit on the remote to the base module via rf,
which looks up the x10 code to send and sends it.
I hope this sketch of an approach is not too high level.
If it was and you were looking for specific part/solution ideas I apologize.

dt
.



Offline Soeren

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Re: Sense what room you are in.
« Reply #4 on: October 14, 2009, 10:56:37 AM »
Hi,

You are missing two important requirements, low cost and low installation impact.
Then you should have put them in the original post ;)
When no criteria is given, I weigh stability and function the highest - but nobody is forcing you to do things my way.


I am still not convinced my idea won't work. Some moderate googling has revealed that not only have others done this, but there is actually a patent for this exact method of room identification;
Oh, then just copy the patent (you know, functionality isn't necessesarily implicit in a patent, only originality in some sense, so perhaps give it a critical look over).


and some the high-er end Roombas can tell what rooms they are in by using infrared "lighthouses".
By all means, go ahead if that's what you want.


I already assume i will be pointing my 'remote' at a light to turn it off/on, like you point your tv remote at your TV. And i will code it to keep it's room identification remembered until it reads another room, meaning i will only need to point it at the light once until i change rooms.
Then ask no more... Construct and experiment, that's the best way to learn.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline chasternet

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Re: Sense what room you are in.
« Reply #5 on: October 16, 2009, 09:00:47 PM »
why not have an ir receiver in each room, so that you can have one output that, depending where it is picked up it could tell what room its in, then you could also have isolated systems in individual rooms

Offline madsci1016Topic starter

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Re: Sense what room you are in.
« Reply #6 on: October 16, 2009, 09:30:20 PM »
The simple answer is, my way keeps the system simple and cheap. You can have a few IR LEDS and a 555 timer pulsing out a different sequence in each room, and a single receiver in the controller. The beacons would only cost a dollar or two.

The way you suggested would require running wire throughout the house or expensive mesh radios, that somehow communicate back to the central station that interfaces with the X10 system. 

 


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