Single Receiver w/ 10+ Single Button Remotes

Okay, so at the request of my mother, I need to make a system for my parent's business.

They have a nursing home type business, and I need to make a system that runs off of a Arduino.

There will be 1 base (receiver), and 10 single button remotes that can be wearable around each residents neck (like a necklace).

The base will have 10 LED's and a single Piezo Buzzer. Each LED will be labeled with a resident's name.

Let's label the remotes as "Remote 1 - 10", And the LED's as "LED 1 - 10"

When the button on Remote 1 is pressed, LED 1 will light up, and the buzzer will go off. When the button on Remote 2 is pressed, LED 2 will light up, and the buzzer will go off. And so on...

The range needed will be a minimum of 100 ft, and must be able to go through walls.

What type of setup should I use for the remotes & receiver? I would rather buy the remotes already assembled, if possible.

The range needed will be a minimum of 100 ft, and must be able to go through walls.

Construction? Concrete? Steel? 2x4 and sheet-rock?

An XBee, battery, LED, and switch could be used for a two way sender/receiver. Patient presses button, XBee sends signal, nurse/parent presses button to acknowledge, XBee receives signal, and lights LED to inform patient that help is on the way. Could even use multiple LEDs of different colors, and multiple switches, for different levels of help - need to go to bathroom, need to go to bathroom NOW, having heart attack, etc. A big one for emergencies - small ones for less urgent needs.

On the receiving end, an XBee with Arduino could be used. With proper configuration, the XBee could tell the Arduino who the request came from.

Perhaps not the cheapest solution, but workable.

It's only 2x4 and sheet-rock.

And the only issue with that, is the remote side of it... I dont have any way to make a enclosure for the remote... Plus I was hoping to go a little bit cheaper than a Xbee, especially if I gotta buy 10+.

Jeenodes might be suitable for this. I'm sure they have some form of suggested enclosure. Google Jeenode. Ranges of 100s of feet seem possible. They are pretty cheap - ~$22 a pop (or make your own)

Okay, well the remotes only need to be transmitters... (They won't be receiving any signals.) And I really would like the remotes to be pre-made.

Isn't there a way I could hook up a small garage door opener as a remote?

Here's an example:

Okay, well the remotes only need to be transmitters... (They won't be receiving any signals.)

But if they did they could keep on sending until it was acknowledged , this would avoid clashes and ensure it worked.

True, but the problem is I need to keep it as cheap as possible, while being reliable at the same time. And the remote STRICTLY need to be only 1 button... Adding multiple button add's to the complexity for the residents, and they would get confused.

And again, if I make my own remote, i'd need a way to easily make or buy a enclosure for it.

I have the supplies to make my own PCB Boards, so that I can do... I just suck at cosmetic works (Such as molding plastic, etc.).

Any ideas?

Not sure you understand Mike's point - what happens if two residents press their button at the same time?

I want each remote to have a unique identifier, so the receiver/arduino knows “which” remote was pressed.

Hence the reason for multiple LED’s…
The 10 LEDs will be on the receiver…

Each LED will have a matching remote.

Ever been on a teleconference call were two people say their name at the same time and you understand neither of them as they spoke at the same time?

Okay, well they only have 10 residents, so I don't really think that will be an issue..

How many milliseconds or seconds are we talking about the collide time? My guess would be less than 100ms, right?

It's a small environment, so I don't really think that would be a problem.. If the unique ID of a remote don't match up, then the receiver will just ignore it... I think that should be fine...

For the residents, suggest making a simple circuit consisting of: atmega168 8 MHz xtal, two 22 pf caps 10k reset resister two 100nf caps on VCCs

(or a 3.3V/8MHz promini if you want to buy one)

LiPo battery button 434 MHz RF transmitter, connector to plug in to a battery charge station every couple of weeks.

Minimal connections needed, hot glue the board into an enclosure, drill two holes to mount button and 1/8" mini jack for charging.

Short sketch consisting of button read to interrupt from powerdown sleep mode, virtual wire to send out a message, go back into sleep mode.

Base station will be similar, with LEDs/Buzzer. Powered on all the time listening for transmissions

Sounds like a fun weekend or two assembly project once the parts are obtained.

If you don't mind a little clunky looking, the Really Useful Boxes that Staples, Office Max carry are pretty durable and easy to work with. Add a couple of screws to secure the cover and not rely on the flip plastic handles.

I wouldn't worry about collisions - just have the transmitter send out its message a few times at differently spaced intervals from each other.

If the unique ID of a remote don't match up, then the receiver will just ignore it

So two people have pressed and you ignore them both? I would have thought a better strategy would be if you get an unidentified number the go check all 10 residents. The other problem is that you probably can't guarantee 100% coverage 100% of the time no matter what the power of the transmitter. The antenna may be blocked or screened or at the wrong angle.

I have worked on alarm systems like this for a commercial company and it is not as straight forward as you might hope.

Without feedback - wont residents just keep punching the button until someone arrives? With a two way system the base station would respond back to say "message received help is on it's way" and turn off the button until acknowledged. Having tried to teach numerous erm more senior family members how to use technology over the years, I've learned that the "mash the button as many times as you can" school of thought is the default setting. If this fails they fall back to "push the button harder" approach.

If you do go with those cheap transmitters - I'd strongly suggest that you ensure that they are FM based. I tried a couple of AM based ones a while back and they are terrible in terms of range.

True, maybe an LED that will light for a unknown ID. Good idea!

But as for making my own remote, I could, but i'd rather not.. I'd rather use a keyfob remote from:

As for collisions, I'll just add the LED for a Unknown ID.

Could always turn on an LED after the button press so they can see a message went out - make it flash or something distracting.

Those keyfob remotes look good too. Wonder how much.

Let me know on the pricing from Linx. If the can beat $22 each - I'll be giving them a call myself. :D

I'll let u know once they open in like 10 minutes... I'll be calling them!