For some of you who live in older homes, the feeling of too cold in the winter and too hot during the summer comes with the package. Last year, I thought of getting spray foam installed and figured now is the time to start analyzing the some of the data I’ve been collecting over the past three years. I told the installer that I had three years of data and would do a before and after test to see what the spray foam did in terms of performance. He stated he would purchase the data analysis. Needless to say one could just look at the heating bill to see if there is difference. With variance in unit costs of fuel, admin, etc., I did not want to bother normalizing that info. The geek in me wants to explore data mining and inference. So off I go to explore Linear discriminant analysis and random forests.
For this exercise, I had three in-home temperature points, one outside, and several power related measurements. So far I had close to 3 million data points. I searched the web for an open source toolset that could help me with data analytics and decent plotting capabilities. Given I used the R programming language a few months back and liked the graphing capabilities in the ggplot2 package, it became my tool of choice. Note that Python is making in-roads in the data analysis space and for now, I want to remain focused on data analysis so R it is.
The idea of setting up a surveillance system has been on the to-do list for a long time. Given there have been a few break and enters in our neighbourhood for petty stuff and the last straw was a break-in in my vehicle, I decided to set one one up. Why make it easy and purchase a ready to go camera like a foscam? It is would not be as exciting. After some searching, I ended up with purchasing the following from Newark Element14:
- 2x -RASPBERRY-PI-RASPBERRY-PI/8GB-USD-MODEL B – 8GB SDCard W/ NOOBS PRE-INSTALLED
- 2x – ADAFRUIT INDUSTRIES-1012-USB WIFI MODULE, 802.11b/g/n, RASPBERRY PI & BEAGLEBONE
- 2x – RASPBERRY-PI-RPI CAMERA BOARD-ADD-ON BRD, CAMERA MODULE, 2RASPBERRY PI
- 1x – RASPBERRY-PI-RPI NOIR CAMERA BOARD-CAMERA BOARD, BCM2835 RASPBERRY PI
I got around to set up the 120 GB SSD on the quad. I ended up making my own power cable with header wires to connect to +5 and Ground pins. I could not find a power connector that fit it J12 on the board at the local stores and didn’t want to order a small part online and pay for shipping. What I have works.
The process was rather painless at first. I followed the procedure for creating a bootable image via OSX as described at the Udoo website. I then booted the board with the newly imaged SD card with the SSD connected to the board. I then installed gparted via
sudo apt-get install gparted
to partition the SSD and also create another partition on the SD card for backing up stuff since I had about 23 GB extra on the card to use.
I received my UDOO Quad today. I was not expecting to dust off my faithful home energy system I wrote a couple of years ago. It has been running well yet I feel guilty of having a home computer running 24×7 to act as my SCADA host. The UDOO is the board that will blend both the Arduino and Linux in a nice board and allow Solid State Drive to hold all the data. On its own without a SSD it consumes around 3.7 watts in-standby.
I currently have about three years worth of energy and temperature data that I also don’t want to lose and it has to be migrated as well. I’m hoping to analyze it using the R-Language one day. I’m hoping that it should be a relatively easy port as everything is cross platform.
Why GNU Octave
Learning image processing using C++ is not practical for a newbie like myself as it is not conducive to trial and error. Besides, I would like create a model and explore it in an iterative fashion before I code it in C/C++/ObjectiveC.
I opted to install GNU Octave on the Mac Mini since all my dev is on that platform. I did install it on Windows 7 a while back for an earlier project so I know what it can do. I also wanted a tool that was almost 100% compatible with MatLab code.
Installing GNU Octave
My dev box consists of a Mac Mini with 2.3 GHz Intel Core i7, 16GB RAM running OS X version 10.8.3 (Mountain Lion). There seems to be a lot of issues with installing Octave in OS X based on what I see on the web. I went down the MacPorts path since I used it for some other installation.
I read yet another book on iOS development and got the creative juices flowing with lots of ideas for some image processing. That said, I’m starting to feel like a hoarder of electronic parts and opted to put a couple SeedStudio Water Flow Sensors to some use. Besides someone asked me to describe how to use them in simple terms. So this side trip’s goal is put something together to measure the flow from kitchen faucets. The functional requirements include the following:
- Hot water line measurement
- Cold water line measurement
- Current flow rate in L/sec
- Running volume for the day in L
- Max flow Duration for the day in seconds
- Min flow Duration for the day in seconds
- Average Duration for the day in seconds
- Total flow duration for the day in seconds
- Integration with my existing M2M Mango instation over Modbus
Time to explore something outside my comfort zone. Image Processing. I’ve gone through a few geek books during hard to find spare time. There are so many apps in the iOS world that I needed to dig a little deeper to get a better understanding what is under the hood. iOS Programming: The Big Nerd Ranch Guide and Objective-C Programming: The Big Nerd Ranch Guide are good introductions. If you know C/C++ the Objective C book can be read rather quickly. I liked going through the exercises in the iOS programming book (well kindle version) to force me to navigate through the xcode/iOS documentation. My real motivation is to do some image processing and opted to read the OpenCV 2 Computer Vision Application Programming Cookbook.
I finally got around to tinker with things again and opted to digress from the zigbee standalone mote-like development to revisit the power measurement.
I have three types of sensors to measure currents lying around and decided that given I already wrote the C++ classes and modbus integration for total home energy consumption, I could easily create a spot measurement modbus slave device to monitor specific loads. Note that all my arduinos+zigbee are modbus slave devices and only the mote-like devices shall use a different protocol.
Making it work.
I got everything to function with a rather messy board setup as shown below.
The output from the Arduino shows the delta T between messages received from the end-devices. It is pretty close to the calculated ones. I will change the duration to be 15 minutes later on but for debugging purposes 10s intervals for pin sleep is tolerable.
Well everything is wired up and works as planned. Sort of. The journey there was not simple. The datasheets on the xbee around sleep modes covers everything one needs to set that up. The problem is that it is not a first pass approach for a newbie. I had to scratch my head a few times.