[Bithead’s] already built some home automation to control the lighting and temperature in his house while he’s away, but he wanted to take things a step further and have the house automatically anticipate his arrival and adjust the environment accordingly. The project takes advantage of geofencing to create a perimeter around the home that listens for a transceiver in [Bithead’s] car. We featured a similar project with a Raspi a few months ago, which locked the doors upon driving away.
[Bithead’s] implementation uses a pair of Digi Xbee Pro XSC radios with U.FL antennas to provide an impressive 2+ mile range of communication. The home-based Xbee hooks up to a Parallax Xbee USB adapter and subsequently into his computer—its antenna sits in a nearby window on the top floor of his house to maximize range. For his car, [Bithead] originally opted for an Xbee shield and an Arduino Uno, but he’s recently overhauled the build in favor of an Arduino Fio, which reduced the footprint and increased the range. Check out his page for the build log specifics and more pictures.
hope he has the right keys so that his house does not get overly friendly.
> So, I cut the connection to Pin 1 of the Xbee and wired up a voltage divider using 2
> resistors to get the 5V input down to 3.3V needed by the Xbee.
Ok, maybe I’m missing something, but wouldn’t it have been easier and better to simply use your smartphone and write an app, or use something like tasker?
You could record a precise route and report it back to the house so you’d know whether the travel is towards or away from the house, ETA, and have one for each family member.
It’ll still work if you’re on a bike, being dropped off by friends, on foot etc..
Hardware cost is zero.
A constantly broadcasting beacon seems like a bit of a kludge.
even easier than that, raspberry pi with BT dongle looking for your phones Mac address.
Easier than that is a config I used to have.. send your WiFi AP syslog output to the home automation controller and grep for a DHCP request by your mobile. I keep my mobile’s wifi on all the time. No additional hardware required.
The problem I had with this approach, and the reason why I suggested a custom app or tasker is that WiFi range is only tens of meters (which is still more than a BT solution).
Another problem I see with the constantly broadcasting beacon approach is that if you work within 2 miles of your house, or regularly go somewhere within the radius (pub, friend, mother, in no particular order) there will be false positives.
That’s why I suggested a solution which also reports your location and trail – you can then guess intent.
Bluetooth has a range of only 10 meters. WiFi has a longer range, but still not nearly long enough. I needed something with long range so the house has time to adjust temperature before I arrive – it takes time to raise the temperature in the house 2-3 degrees.
In order to avoid false signals, I have the house delay the beacon start for 10 minutes. That gives me plenty of time to get our of range. The car has a feature that kills the power to the cigarette lighter so when the car turns off, so does the beacon. I rarely get a false signal.
In fact, I initially started down that path, but could not get a reliable fix on my location to initiate the goefence.
This is upgrading home remote control to home automation. He never had home automation until now.
I’d invite you to read my blog. Many of the features beyond this are true automation.
http://bithead942.wordpress.com/category/home-automation/