outdoor keypad or keyfob for alarm system

[pat]

I would like to build a wireless alarm system for my house.
Mysensors concept seems to be wonderful. It can provide everything I need:

• wireless motion sensor
• arduino gateway, repeater.
• price is low
• low consumption: this point is important to avoid changing the battery every month.
• security is acceptable as long as the sensebender is added to the system to provide authentification.
• flexibility is infinite.
• controllers as domoticz or Jeedom based on raspberry can be used to have a nice user interface.

I just have an issue with this project: I want my children be able to easily deactivate this alarm from outside when going back from school for example.
The 1 st solution would be to use an outdoor numeric keypad (SparkFun COM-08653 for example) controlled by an arduino + RF. This keypad system will be able to communicate by radio with the arduino gateway located inside the house. So far so good. But there is a little detail that bothers me: I can't find a nice enclosure for this. My issue is not electronics/programmation. My only issue is: how to put the keypad+arduino+NRF2401+battery inside a nice box to be put outside near the door.
Anybody has a good idea for any nice box / enclosure for keypad?
The second solution would be to use keyfob for each member of my family instead of a unique keypad. But I can't find any keyfob 433Mhz solution able to communicate with an arduino gateway. Anybody can help me for this ?
Of course, I am also open to other solution.
Thanks.

[hek]

Might be easier to hand out RFID tags to your kids.

[TheoL]

@pat I'd personally would never put my numeric keypad outside the house. The key to your door is the first factor of authentication. But a burgelar can get arround that very easy. If you put the numeric pad behind the door (in your house) you have to be able to get into the house before you can deactivate the alarm. So the numeric keypad acts as a second authentication factor.

In order for your children to have time to enter the code. You could add a door sensor, which can be cheaply done using a reed relais and a magnet. Which will cost you around two dollars. So whenever the door is being opened. The reed relais will lose connection and that will be noticed by your domotica controller. Which than starts a timer of about one or two minutes before the alarms turns on. In the mean time, if someone enters the right code on the numeric keypad the alarm wil be turned off.

Another thing that would concern me, is that the box in which you'll put the numeric pad should be realy strong when you put it outside. You don't want it to be easy accessable for people with the right amount of knowledge to by pass the numeric pad, so that the alarm will be activated. So it has to be from some sort of metal. I'm concerned that a metal box might be interfering with the radio signals.

If you do want to be able to deactivate the alarm from the outside. You could consider to use an RFID reader. Though RFID tags and cards like MiFare can be copied as well. Which in my oponion isn't realy secure. Must systems that use RFID as authentication, use that as a first authentication factor. A second factor is mostly fingerprint. But systems like that are really expensive. And I'm not sure if I would like it if information like this will be transmitted wireless to a server.

[sundberg84]

I use geofence (Pilot for ios and domofence for android (for domoticz)), triggering a virtual switch when we are home.
Then my alarm is set to arm away if all switches are off and arm home if its night and so on...

Only problem when mother in law decides to come visit without notice :) need to add some sort of tracker there...

[pat]

Thanks you for your answers guys.
I like the innovative idea using geofence. But it has the drawback to require a full time internet connection in the smartphone, which is not the case for my children.
And I agree with @TheoL that an inside numeric keypad is safer so I will finally focus on that.

[TheoL]

@pat I thought about the idea of putting a wireless keypad outside of your house a bit today. I don't think it's a good idea. If someone steals your keypad you won't be able to turn off the alarm. So you can't get into your own house.

[sundberg84]

@pat well the geofence pretty much hit when i connect to my wifi, since Google locations use wifi to find the loc.

Another is a manual switch in your smartphone which children can trigger outside the door connected to wifi.

[bjacobse]

If you children uses a smartphone. You can write some code that on your server, is asking on the MAC addresses on your LAN, if your specific MAC address is attached to your LAN, you can then unlock the dorlock
Agocontrol.com have this kind of code :-)

[malarcy]

How about iButton?

wikipedia 1wire and iButton

Basically the system that we (at least in the UK) see a lot in point of sale devices where different users identify themselves to the the system - I have not seen any iButton implementations for MySensors - but we do have the 1wire library.

There are a lot of cheap key fobs and readers available - I am going to use one to allow me to override the house/garage alarm when I get home 1st and want to put the car away before entering the house and disarming the alarm.

[martinhjelmare]

I'm planning to use my Yubikey Neo as key to the alarm system. It has NFC and it's more secure than just an RFID tag. It can do SHA1-HMAC among other things. You can combine that with a passcode and have 2FA.

Only downside: 50$ a piece. But it's a very versatile security gadget, and for me, it's worth it.