Our current alarm system was getting cranky after 7 years so I began research for a replacement. The current alarm system manufacture advertises that it is not for DIY and I could not make sense of their new product line anyway so an upgrade from the same company was out. I was happy with their 5+ years sensor battery life but little else. Weeks of frustrating due diligence produced little in the way of new possibilities. I am not interested in a system that requires an account on a companies web site which in many cases means control of the system through their website requiring access credentials to my local net.
Reluctantly I decided to look into a "roll your own". A little experimentation convinced me to give it a try. The new system consists of just one type of sensor at this time (a window and door magnetic switch) connected to a Motino. Each motino sends periodic messages to a central motino which reformats the message and sends it via serial cable to an Intel NUC that I bought some years ago. I upgraded the OS on the NUC to the new Ubuntu LTS, added nginx, G++, and SSH. Reporting and Control is through a web interface. I can pick up any tablet or smart phone around the house to view and control the system.
After poor experiences with ZWave I felt it necessary to be able to measure and understand the behavior of the network. The spread sheet looking image below shows the web page that displays network behavior. I am seeing about a 1% packet loss which is better than I hoped for and a relatively consistent signal strength reading from the nodes. The RSSI column is an average of the last 5 readings. At his time the nodes wake up every 4 seconds to check the sensor and every 30 secs (or so) to report in to control. These values will change during roll out. Node # 6 does not exist, it was added to test "last heard from" processing. I am more interested in the relative change in battery voltage rather than absolute accuracy. During 3 weeks of testing the batteries (3 well used AA cells) for node # 2 have decreased by 0.03 volts. The plan is to use 3 AAA cells but that may change after further testing. During sleep mode each remote node uses about 11 microamps.
To further understand the network behavior the last 60 readings of RSSI are saved and can be plotted. A sample plot is displayed below. The happy conclusion (for me) is that the readings are consistent although it makes for a boring plot.
The main control page has oversized buttons so it will be easier to use from a touch screen tablet and smart phone. The alarm system can be changed from OFF, to AT HOME, to AWAY. Alarms that occur when the system is set to AWAY or At HOME are send out via SMS and email. The second row of buttons provides the ability to turn SMS and Mail off to prevent an accidental flood during testing. The middle button on the 3rd row displays overall alarm status. The bottom row has only 1 working button (Network) which calls up the Net Status page. The net status page is refreshed every 15 seconds. A PHP TCP connection to the control program provides exchange of commands and information between the control program and server side PHP code.
The remote nodes still have to be packaged which will stress my non-existent mechanical abilities. The plan is to then add other types of nodes (temp, humidity, motion,...), improve the network instrumentation, and continue to develop the control software. 5 More motinos are on order.
Since the RFM69 radios worked out of the box the RFM69 software is still a black box to me. I have read some conflicting information about interrupts on the arduinos and expect to come back to this forum with a few questions (perhaps more than a few).
This has been and continues to be great fun to work on. I'm not sure about the appropriate image size for attachments. Be happy to post larger images if these are too small. I hope this has been worth your reading time.