Overall a result!

I think the phasing out of incandescent bulbs is long overdue. I understand phasing out halogen bulbs is also on the cards. Makes sense.

Background

The wardrobe of hers occupies a whole wall of the bedroom – probably 4m of wardrobes. My wardrobe space, on the other hand, occupies a width equal to the wavelength of light. They are fairly standard Ikea jobs that I installed 6 years ago when we moved in. They are against an outside wall of a house built in the 1910′s, ie no cavity insulation etc, and areconsequently rather cold and stuffy.

Two hours of dismantling a section of wardrobe revealed no damp, gushing pipes or Cornish water pixies. What I did discover were clothes packed so tightly that not even the tiniest wiff of air could circulate. My suggestion that maybe a cloths “cull” could be the answer was rightly met with a blow to the back of the head. An alternative solution had to be found.

Being of the geeky persuasion, I have a number of PC carcasses spaning two decades in the garage. The common element to all of them is the humble fan. A quick trip to Bodge-it and Quick, and I had myself a 70mm hole cutter and a number of vents. I’ve drilled two 70mm holes in the bottom of the wardrobes and two 70mm holes in the top. The bottom holes have been filled with the vents and the top ones have had 80mm fans placed over them to suck the air out. The 12v for these fans is being supplied from an old phone charger and is on a timer plug. The timer is set to come on for an hour a day when we are at work. Will it work?

Disclaimer

My wife is a saintly, mild mannered angel who wouldn’t hurt a fly (apparently it ruins the taste)

*otherwise known as the “Eric Pickles at a free buffet phenomenon”

• crap everwhere
• dig up the lawn and vegetable patch
• chew through everything, including goal netting, toys and garden hoses

All in all I’ve have enough, especially with two young kids – the 2 year old is afraid to go out in the garden because of the foxes. I’ve already tried the deterrent powders, ultrasound devices and better fencing, but none of them work. After a bit of googling, it seems that the most effective (non-lethal) method is an infrared sensor attached to a water sprayer. They are widely available online as a complete package, but where’s the fun in that? 

So, I present, the FoxDuino ……well sort of. I’m awaiting a couple of parts but the basics are there and comprise

• A jeenode (arduino clone) – I’ve a few lying around
• A PIR sensor - on order £6.51
• A 12v DC Solenoid Valve – again a couple of these in the garage
• Hose pipes and sprayers – again, no shortage of these.

It’s quite simple really – Mr Fox triggers the PIR and the jeenode switches on the sprayers for 5 seconds in a nice sharp blast. Given the jeenode’s inbuilt wireless capabilities, I’ll get it to send out info on activation times etc.

More to follow when I’ve built the thing!

I’ve looked at a number of approaches, including monit, but have never got any of them to work very well. So step forward Upstart. From the website -

Upstart is an event-based replacement for the /sbin/init daemon which handles starting of tasks and services during boot, stopping them during shutdown and supervising them while the system is running.

You can add a service to upstart by adding a configuration file to /etc/init/ and then running “sudo initctl reload”.

Here’s my config file for my python script

description “CurrentCost Monitor”
author “meeee!”
start on runlevel[234]
stop on runlevel[0156]
script
chdir /usr/bin/scripts
exec /usr/bin/python currentcost.py
end script
respawn

There’s probably more in there than there needs to be, but so far it’s been working for a week with no problems, so I guess I’ve got a working solution.

Anyway, a big thanks to Upstart and the team that are working on it!

• 1-wire
• arduino and jeenode
• currentcost
• the joggler
• a cheapo USB controlled 8 way relay from ebay

1-wire

These were originally from Dallas Semiconductor, but  Maxim have now carried the brand forwards. They are not an open source design, but the individual components are cheap, and a good community has developed to provide open source libraries. The devices can be connected together in a chain using simple telephone wire or cat5 – the maximum cable length is about 100m. Libraries have been written for the arduino to interface with these chips. A number of chips are available from temperature sensors to A/D converters and relays.

Arduino and Jeenode

The arduino is an open hardware platform based around the ATMega series of chips. As the platform is open, a number of clones have popped up including the jeenode, which handily integrates an RF12 radio module at a price that won’t hurt your pocket too much. Additionally, the creator (‘JCW’) blogs well and frequently, and is very helpful on the forums. They are programmable in C/C++ – not languages that I’ve had much previous experience, but it’s been fun nonetheless.

At my (medical) practice, we’ve put a number of jeenodes in the vaccination fridges to keep an eye on temperatures etc, logging to a central database – fairly basic in the scheme of things, but welcome change from the twice daily manual measurements and excel spreadsheets!

The Currentcost Envi

Not much to say here, but these energy monitoring devices are now fairly widespread, with some energy companies sending out units to customers for free. They are available with a serial – usb connector for linking up to a PC for data logging/analysis. I’ve written about them before here.

The (O2) Joggler

These touchscreen Atom-based small PC’s have been sold by O2 in the UK for approximately 18 months. In the Spring, O2 dropped the price to £49.99 inc shipping and naturally a lot of folks snapped up the offer. The default software is a very stripped down version of ubuntu with a flash based interface on top. It uses EFI rather than BIOS which makes installing another OS a bit tricky. It also has only 1gb of on-board flash. A number of people have devoted their time to getting other OS’s running, including Ubuntu 10.10 and Linux Mint.

Actually, when you look at it, only one of these pieces of hardware is Open Hardware (the arduino), but all are relatively inexpensive and have OSS libraries etc – which brings me to to the crux of my problem – each of the hardware solutions above have their pluses and minuses, and each will serve my needs in various ways, but how to plug them all together to create a modular, flexible, yet integrated system? Many people with far more talent in this area, such as Andy Stanford-Clark, have developed their own solutions. What I’m trying to do is develop a framework that I can grow as my knowledge grows.
But it needs a ‘backen’d to connect it all together. The rather excellent mosquitto project, by Roger Light has really grabbed my attention. It’s an “Open Source MQTT v3 Broker” (to quote Roger) that has packages for ubuntu, amongst others. He’s also put together a rather nice python library (my programming language of choice, just because that’s what I stumbled on first). An initial sketch of what I envisage….

The area I’m going to start on is the Mosquitto-Python Layer-Web Interface bit. The big question I need to know is there an OSS solution I’ve not found that does the same thing? Any feedback welcome…..

I tried LED GU10′s about 2 years ago and found them expensive and the light emitted far too ‘cold’. A couple of months ago I decided to give them another go and things seem to have progressed nicely. An eBay search coughed up a number of suppliers with a wide array of light colors and led numbers/bulb. In the end I went with this http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170565002537#ht_1468wt_907 (disclaimer – I have no commercial interest or connection with this seller!) and chose the 48 led ‘warm white’ at the very reasonable price of £4.29. They draw only 3w each and I actually prefer the light from these compared to the halogens. The seller claims that the bulbs last for 50,000 Hours. I’ve only been using them for 2 months, so I have a long way to go before I can confirm that claim (25 years!). In summary, from a total estimated annual electricity cost of £120 (+ cost of replacement bulbs), we’ve now gone to an annual bill of £9! By my estimations, the bulbs will have paid for themselves within 6 months.

A serial port to usb adapter is available from the manufacturers for about £10, but a quick trip to google revealed that many mobile phones shipped with a USB cable that was in fact a USB – serial converter. I never throw anything away – to my wife it’s my deepest character flaw. Needless to say a quick rummage in my man drawer yielded 6 mobile phone USB cables. A win for the man drawer! (If the portuguese escudos ever gets reintroduced, I’m quids in by the way). Plugging them into the laptop and checking dmesg showed that 2 were indeed usb-serial cables. 10 mins with a soldering iron and an rj45 plug, I had a rather ugly, but free, usb-currentcost adapter. It’s now plugged into my revo running ubuntu 10.04.

There’s loads of info on the interweb about the structure of the XML feed that the currentcost device produces.

http://stanford-clark.com/power/

http://chemicaloliver.net/programming/mqtt-mosquitto-and-php/

http://code.google.com/p/currentcostgui/wiki/MQTT

http://andypiper.wordpress.com/2008/04/27/current-cost/

I am not a natural coder, but when I do, python is my language of choice.  It’s pretty simple to get at the serial port with the python serial module and then parse the xml data into something useful. Here’s the code I’m using – you have been warned, it’s ugly!!

#!/usr/bin/python -u

import re
import MySQLdb

dbName = "db"
tblName1 = "power"
uName = "username"
pswd = "password"
hostName = "mysql_server_IP"

import serial
import shlex
import subprocess

pub_cmd = "mosquitto_pub -t cc128/raw -l -q 2"
pub_args = shlex.split(pub_cmd)
pub = subprocess.Popen(pub_args, stdin=subprocess.PIPE)

ser = serial.Serial(port='/dev/ttyUSB0', baudrate=57600)
db = MySQLdb.connect(host=hostName, user=uName, passwd=pswd,db=dbName)

c = db.cursor()
prevWatts = 0
deltaT = 0
prevTemp = 0

while 1:
        line=""
        line = ser.readline()   #read a '\n' terminated line
        pub.stdin.write(line)
        pub.stdin.flush()
        print line #prints the output so you can see it working
        m = re.search('.*[0]*([1-9][0-9]*).*',line)
        n = re.search('.*([0-9][0-9]):([0-9][0-9]):([0-9][0-9]).*',line)
        o = re.search('.*([0-9\.]*).*',line)
        if m is not None:
                watts = m.group(1)
                hours = n.group(1)

                mins = n.group(2)
                secs = n.group(3)
                temp = o.group(1)

                totalTime = (int(hours)*3600) + (int(mins)*60) + int(secs)

                if deltaT == 0:
                        deltaT = 6

                else:
                        deltaT = int(totalTime) - int(prevTime)

                prevTime = totalTime
                deltaTemp = float(temp) - float(prevTemp)
                deltaW = int(watts) - int(prevWatts)
                joules = (prevWatts + int(watts))*0.5*deltaT
if (deltaW >= 40) or (deltaW <= -40):
                    c.execute("INSERT INTO power (watts, joules) VALUES (%s, %s)",(watts,joules))
                    print watts+"W"

                    print hours+":"+mins+":"+secs
                    print temp+"C"
                    print deltaT
                    print deltaW
                    prevWatts = int(watts)
                else:
                    print "No Change"

pub.stdin.close()

pub.wait()

Where does this put the data? Mainly it’s into a MYSQL database with three columns – stamp (timestamp, default value current_timestamp), watts, and joules. It’s also publishing it to a mosquitto instance running on the same machine. Mosquitto is an mqtt message broker as used by Andy Stanford-Clark in his twittering house. I’m just messing around with mqtt and I’m not entirely sure what I’m going to do with it, but what the heck.

The next stage is to graph this data to get some meaningful power usage pattern and display it on a webpage. Initially I used matplotlib, but nice as the graphs were, they loaded way too slow. I’ve now moved to using google visualizations, the associated python API and an addon for it called dygraphs. This now produces rather nice interactive graphs that can be seen here.

Rather worryingly it shows that the house has a ‘resting’ power need of about 400w. It was probably more – I used to leave two ‘servers’, the laptop and a macmini, powered on 24/7. I now use wakeonlan to power these up if needed. So now the only PC’s permanently on are the revo and a viglen mpc-l. Between them they probably only account for about 35W. I’ve also installed granola on all my machines, which seems to be improving energy use.

On the domestic appliance front, the main energy gobblers are the oven, tumbledryer and dishwasher. I rather think the chest freezer in the garage may be accounting for some of the baseline consumption – it’s about 10 years old so may need replacing. To further isolate power usage, CurrentCost have some new “Individual Appliance Monitors” coming out soon, which will link into the CurrentCost Envi base unit. I will be first in the queue.

In the meantime, I’m taking the plugs off the tumbledryer, dishwasher, wife’s hair straighteners and her hairdryer. In retrospect, maybe not the last two…………I’m not quite that stupid.

I didn’t always agree with him, but he’ll be missed.