Long Range RF
Tim-M
Posts: 522
My wife and I care for her 89 year old father who lives on the property adjoining ours. We check on him several times a day, but I'd like to put a project together that would allow him to get our attention next door if he would like to or has an unexpected emergency. He has no telephone and refused to use one when he had one so I'm thinking that maybe an RF solution may work well. We need a reliable 1000 foot range including from inside of one house to inside of the other (so through a few walls too) to make the idea doable. Ideally, the transmitter would be small enough that he could keep it on his person all the time. So far I've been looking at Parallax and Link Technologies products.
Questions...
1. Looking at the Parallax 433MHz transmitters and receivers at the advertised 500 foot line-of-sight range, I would need to make repeaters to cover the property area and distance. As a repeater, it almost looks like a pair of these could be wired together without the use of a microcontroller to get that job done.... has this been done and what are your thoughts on the idea? I know it can be done with a BS2 at the core.
2. What other options do you know of to cover this distance and wide area?
All thoughts and ideas would be most welcome.
Tim
EDIT: In reference to OldBitCollector's trip to Parallax, I believe there was mention of a new, upcoming longer range RF product of some sort... any other clues or info. there?
Post Edited (Tim-M) : 2/21/2009 11:58:59 PM GMT
Questions...
1. Looking at the Parallax 433MHz transmitters and receivers at the advertised 500 foot line-of-sight range, I would need to make repeaters to cover the property area and distance. As a repeater, it almost looks like a pair of these could be wired together without the use of a microcontroller to get that job done.... has this been done and what are your thoughts on the idea? I know it can be done with a BS2 at the core.
2. What other options do you know of to cover this distance and wide area?
All thoughts and ideas would be most welcome.
Tim
EDIT: In reference to OldBitCollector's trip to Parallax, I believe there was mention of a new, upcoming longer range RF product of some sort... any other clues or info. there?
Post Edited (Tim-M) : 2/21/2009 11:58:59 PM GMT
Comments
You can order the xBee-Pro from the manufacturer (Digi). Selmaware (www.selmaware.com/appbee/index.htm) may have some more PCBs for the xBee-Pro and the Stamp Board of Education. The remote control transmitter/receiver comes in all sorts of variations. Here's one kit that includes everything to provide one or two switch closures: store.qkits.com/moreinfo.cfm/qk157.
Post Edited (Mike Green) : 2/22/2009 12:19:41 AM GMT
Thanks much,
Tim
P.S. I still want to hear any and all ideas...
http://www.sparkfun.com/commerce/product_info.php?products_id=559
Post Edited (SRLM) : 2/22/2009 1:35:07 AM GMT
On this page:
http://www.digi.com/products/wireless/point-multipoint/
I'm not even sure which xBee-Pro series is most correct... items 1-3??
Out of those modules, how do you make heads or tails of all the antenna choices without some expertise??
Thanks for the help,
Tim
Thanks for the product link on SparkFun, that looks like a really nice fit for this purpose too. I like that the buffering and error detection is all handled sight unseen for you.
Great information and solutions,
Tim
Post Edited (Tim-M) : 2/22/2009 3:18:56 AM GMT
You want the -Pro version with the U.FL antenna connector (the only external antenna version) - XBP24-AUI-001.
You'll need the A24-HABUF-P5I (2.4 GHz Half-Wave Antenna, Articulated bulkhead mount, U.FL female, 5" pigtail, 2.1 dBi)
One thing to keep in mind with 2.4GHz signalling ... It's mostly Line-Of-Sight. If it's not visible, it may not be reachable. Heavy rain and really wet tree leaves interfere with the signal. You can make a little "corner reflector" for your antenna that will concentrate the signal in one direction (www.imod.co.za/wifi.pdf and imod.co.za/2007/12/14/building-a-wifi-booster-diy-style/). One of the advantages of putting both units (with the xBees) on the 2nd floor or in the attic is that it can better be line-of-sight and may be mostly above the trees depending on your area.
As far as the property and line of sight is concerned... we do have many trees to deal with, but most of the foliage starts at about 15-20 above ground level and goes up from there. Within the range of ground level to about 20 feet, it's basically line of sight, smooth tree trunks being nearly the only exception. In this case does transmitting altitude or line-of-sight take priority?? My lack of experience shows through here, but I'm sure both height and line-of-sight would be ideal. Also, we're in western Washington (north of Seattle and Everett) so rain is very common, but not heavy rain... more like heavy mist most of the time.
The corner reflector sounds like a good plan for the fixed sights like the house and barn. I think trial and error would have to tell the rest of the story for a portable receiver in the yard or pasture.
How do different frequency ranges, 900MHz vs. 2.4GHz for example, handle rain, foliage and light obstacles like what we're discussing here? Which penetrate better, or do the line-of-sight basics apply across the board?
Thanks for the RF-101 tips and education,
Tim
Have you (or anyone else) used the long range radio modems that you recommended from SparkFun? If so, how did they perform for you? It would be good to hear about some first-hand set-up and use.
Tim
www.midlandradio.com/comersus/store/comersus_viewItem.asp?idProduct=5551
Post Edited (kelvin james) : 2/22/2009 5:14:30 AM GMT
I haven't tried the sparkfun ones yet since they're too expensive for me, but they're on my list... Anyway, what about having a three part system: Your house, your father's house, and your father. Your father has a lightweight and small pack that transmits to his house, and his house transmits to you. That way, he can roam all around.
Another thing you may want to look at are the cell phone modules that spark fun sells. If you get reception in your area, that would probably be the most efficient solution. I wouldn't have to be a phone, it could have two buttons: one for attention, one for emergency. If I remember right, there is a project somewhere where a parent made something very similar to that for their handicapped child.
www.kenwood-electronics.co.uk/products/comms/license-free_pmr446_radio/
Leon
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Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
Post Edited (Leon) : 2/22/2009 9:45:56 PM GMT
-Phil
Kelvin and Leon - The radio idea would be a great turn-key solution, except that they may be a little too complicated for my father in law to operate. He has periods of mild confusion and because of this our thought has been 'the simpler, the better'... maybe even to the point of one large button only.
Phil - First thoughts had been along the X10 line as well. Since I've been using some X10 gear here at home for years, testing was as simple as, well, testing what I already had at hand. As it turns out, the two houses are fed by different transformers so the signals do not travel house to house. Too bad.
After a long talk with my father in law about this project, he doesn't like the idea at all... says it a waste of time. His answer as to Why is it a waste of time? is that I need to consider his point of view... "I'm at the end of my life and will be dying soon, the sooner the better." Since he has no telephone, and won't use one if he did, we have an agreement that if he wants to get our attention between visits, he turns on his flashing porch light and we will come as soon as we see it. When I tell him that this could mean a wait of 1-2 and maybe even 3 hours depending on our circumstances, he reverts back to his point of dying soon and why do we need fast response time anyway. You have to understand that his point is not based on emotion or depression, it's just that he is that much of a practical person. How do you respond to that?!? Pretty rough crowd considering that you're only trying to help him out. I may have to forge ahead with this anyway just to prove that I can be as stubborn as he can.
Tim
Good luck with what sounds like a challenging situation!
-Phil
If you are concerned that you won't hear the foghorn then I might simply point out that your father in law is highly unlikely to look inside the box to see what circuity is attached to the big red button .... an RF transmitter for example ...
David
You sound like a nice guy, with a chronic problem. Take a look:
http://forums.parallax.com/forums/default.aspx?f=25&m=326863
you would need two of these... one for him... one for you. Total cost... about $400. Build time ... about 10 minutes.
Programming time... as much or as little as you want (I'd do it for you).
You can build this very easily... and then you just need a couple of buttons...
one for normal stuff... another for emergencies...
If you run into a problem, I'll help you out.
When grandpa pushes one button... it would send you a txt message... for normal stuff...
For emergencies you can hook up your unit to signal an alarm and call any number you specify.
Before you do anything make sure he is interested. Some old people don't want to kill themselves, but they don't mind the idea of passing away... peacefully and most importantly... at home.
I would find out why he won't use a phone... does he have trouble dialing?... hearing?... remembering?
Does he crave human interaction and has more of it if he doesn't have a phone? IF your creation cuts down on the number of visits he gets... he might not be very happy about it or you.
Rich
If the device he carries is in constant communication with a Stamp in his house, continually checking the link and letting you know when the link is down, that could be autodialed too, with a different notification so you could know whether you got the cell-phone call because he pushed the panic button, or merely because the link was down. This could distinguish between "Omigosh, Dad's in trouble" and "Oops, time for new batteries, let's go see Dad after the movie".
And it doesn't need long range -- the range is countrywide anyway.
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· -- Carl, nn5i@arrl.net
Phil and David - Great idea to tie into the porch light or fog horn directly with additional attention getting methods!
Rich - Thank you for your kind words and offer of help, I really like your cellular idea and project. Great range! The final decision as to what to do is not yet made, but if I cannot get him to use a device in the case of an emergency, I'm afraid the project becomes rather moot, rather quickly. As far as the telephone is concerned, his not using it is not at all a new development or a development with age. He has hated the phone for decades and has rarely ever used it.
Carl - Thanks for your land line ideas too, great thoughts and approach.
I'm going to 'work' on my father-in-law to see if I can sway his opinion on the subject over the next few days, but he is very much the type of guy who does not change his mind once it's made up. We'll see how it goes and I'll keep you posted.
Again, thanks for all the creative ideas and help!
Tim
I'd·install intercoms and cameras in every room and outside his house.· I'd keep the intercoms open all the time so all either of you would have to do is talk and speak up:· no pushing of buttons to talk.· Maybe use a motion detector to activate the cameras so you use them only when he's in a room.· But you could activate any camera manually if you wanted.· You could check on him visually with the cameras.
If his condition is so bad that he may hurt himself, such a being prone to falling down, then I'd recommend he move in with you where you can keep an eye on him or an assisted care facility if you can afford a decent one.· (If you don't have money: poorly run, poorly maintained, under staffed, and unmotivated staff can·make these·facilities depressing.)
jj
Hmmm -- how about a flow sensor on the water line?
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· -- Carl, nn5i@arrl.net
This method really works around the problem of my father-in-law not being willing to use a button of some kind. Once in place and monitoring, we could establish typical intervals for him (for whatever we are monitoring... water use, toilet, etc.) and have the Basic Stamp alert us so that we could check on him if any or all of those intervals run long.
A flow sensor on the supply water line to the whole house is a really efficient way to monitor all faucets and toilets.
Really great thinking Carl... a great combination of out foxing my father-in-law and efficiency. I'm not worthy.
Thanks alot,
Tim
If you're on a well, rather than a municipal water supply, a pump monitor might be easier to install than a flow sensor, assuming the holding tank and associated hysteresis don't introduce too much uncertainty.
-Phil
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· -- Carl, nn5i@arrl.net