Meet the team

November 3, 2009 at 22:09 | In Ones and Zeros | Leave a Comment
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It looks 2009 is the year for people I work with to start blogging, and they’re all on Twitter… coincidence? So if you’re looking for a good read, you might like to check them out. Starting with the newest blog…

October 2009

Ed’s World (@ejellard) Off to a flying start with some great home automation with arduino, Home Easy, MQTT and a helping of hackery.

Limboworld’s blog (@jaylimburn) Conducting a scientific experiment in to the value of blogging, so make sure you get as many people to read it as possible! Some good DIY posts to kick things off. (There would have been a few DIY posts here if I’d started this blog before fitting the kitchen!)

September 2009

The World Of Gavin (@gavinwillingham) Definite technology slant with an enjoyable hint of grumpy old man which I’m definitely hoping will continue!

April 2009

Cobweb (@techcobweb)

Some really varied arduino projects in addition to home automation and tweeting cats. While the only circuit I’ve cobbled together recently is sitting in an ice cream tub in the porch, Mike is a master at packaging projects- his scalextric race timer is a work of art!

May 2006 (so blogging way longer than the rest of us!)

Nigel’s blog (@planetf1)

Not as easy to sum up given the number of posts but a distinct focus on technology of various kinds. Probably need to run it through wordle to get a better idea!

The trouble with making lists like this is that I am bound to have missed a few! I’ll just sneakily add more if I have… which reminds me, I was going to make more of an effort with a blogroll at some point soon.

The cake fairy

September 23, 2009 at 18:33 | In Life, the Universe, and Everything | 2 Comments
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Reentry from honeymoon to real life was softened a bit by this…

HomeCake

…which was waiting for us when we got home this morning.  Looks like the cake fairy got in while we were away! And the milk fairy had restocked the fridge so we could start making up for missed tea without any shopping delays!

It’s been a fantastic September so far, but it’s not over yet. The rest of the month I will mostly be:

  • Married!
  • Unpacking
  • Going back to work tomorrow- urg!
  • Catching up (what’s been happing the last few weeks? Anything interesting?)
  • Writing lots of thank you letters
  • Looking at wedding photos
  • Looking at honeymoon photos
  • Finding out why @jthouse is frozen
  • Working on my second CurrentCost development board circuit (this time sensing pipe temperature- any clues?!) inspired by the homecamp blog
  • Taking things apart
  • Going to another wedding!
  • Other stuff I’ll find out about when I risk looking at my inbox in the morning

But first, of course, I’ll be eating cake! (And sleeping!)

Windy Miller

August 18, 2009 at 21:58 | In Life, the Universe, and Everything | 3 Comments
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A while ago I was reading about compressed air energy storage in natural underground caverns (probably in something from the IET) and I was surprised that something similar doesn’t get mentioned more along with renewable generation like wind power. On the other hand, the unpredictability of wind does seem to get mentioned as a limiting factor much more; understandably it’s a little hard to react to peaks in demand and energy price if you have no control over when the wind blows.

Given the growing number of off shore wind farms, I wondered if wind energy could be stored by pumping sea water out of something like a large diving bell, allowing the water back in to generate electricity on demand. Turns out that ’something like a large diving bell’ is a submerged, open bottomed, anchored caisson.

wind_caes

(cc) some rights reserved. Thanks to phault and Zach Putnam for their photos.

The idea might not get a lot of air time but parliament seem interested in storage techniques in general, and there are examples of the possibility being researched and developed, so there may be a future for renewables without as much baseline capacity required from non-renewables. What do you think?

Update: not for offshore wind farms, but @USR_VRB pointed out a very interesting post about a compressed air project, where the air is used to improve the efficiency of gas powered generation. Some good discussion and links in the comments as well. (4 Sept 2009)

My first CurrentCost development board circuit

June 22, 2009 at 17:59 | In Ones and Zeros, Uncategorized | 6 Comments
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The result of a fair bit of googling and a weekend of hacking is… [drum roll]… a circuit to connect my gas meter to a CurrentCost Envi using a nice little dev board from CurrentCost…

cc-circuit

Now I’m much more familiar with messing about with software, not all this messy hardware stuff, so I’m really hoping to get some feedback to improve this early prototype!

So, my theory is that the stuff on the left will trigger the timer on the positive edge of the pulse from the gas meter. R1 and C1 control the 555 timing; more on that in a second. And the stuff on the right (LED and the CurrentCost dev board) should be triggered whenever the gas meter is running and emitting pulses. It all seems to work, except that I can’t seem to get the timing quite right. The gas meter takes about 1m40s between pulses, and I can choose values for R1 and C1 that trigger the output for the right length of time when a single pulse is detected, unfortunately subsequent pulses don’t keep the output on as I was hoping. The best I’ve managed is with R1 = 3M ohms and C1 = 100uF, which does stay on as long as there are pulses from the meter… unfortunately just for a little too long at 5 minutes. Still, at least the CurrentCost Envi will get a reading all the time the boiler is running, and it won’t get stuck on if the meter stops on the portion of the dial where the reed switch is closed.

Any comments with glaring errors, small problems, improvements, or a completely different way to do it?!

Updated: looks like I was having problems with left and right in my first description! Hopefully I’ve got them the right way round now! (2 July 2009)

Update: for an alternative approach (latching a pulse and clearing it when the cc board transmits) take a look at the circuit and photos on John’s blog. (9 July 2009)

GasCost

June 20, 2009 at 09:21 | In Ones and Zeros | 1 Comment
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I’m getting pretty close to getting the gas meter hoked up to CurrentCost. Not quite the finished thing, but was pretty excited when I got this working…

gascost

It’s a 555 timer circuit (using a low power 555 chip) which I’m hoping will keep the CurrentCost dev board transmitting a value as long as the gas meter is running. I’ve since added a capacitor to trigger on an edge so it shouldn’t keep transmitting if the meter stops on the ‘pulse’ position, which is probably around 1/8th of the time on my meter.

I wasn’t quite sure everything was working when I finished last night, but it does seem to do what I want when I was showing Jo this morning, so hopefully all I need to do is get the timing right for the gas meter, rather than me hitting a button every few seconds. More details to follow if it does work.

Current Cost gas meter monitoring?

May 7, 2009 at 21:45 | In Ones and Zeros | 6 Comments
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As revealed at the second homecamp, Current Cost have a very nice addition to their array of energy monitoring tricks: basically a little circuit board sporting a microchip (a PIC16F689 if my squiniting is accurate) and a wireless transmitter, so the gas monitoring item on my to do list is looking a little more interesting all of a sudden.

Richard has already hooked up his gas meter to Pachube but for a few reasons I have slightly different plans. Firstly, my gas meter is not the same. Possibly better and worse for this kind of exercise at the same time: it has an RJ11 socket for counting pulses… but it is covered and declares that only approved equipment should be used. Maybe not a huge deal, but it is gas and we did have three van loads of people looking for a gas leek in the meter cupboard recently, so kind of keen to avoid any… mistakes! Though I suspect that an optical solution, leaving the meter untampered, would not be any safer but would be easier to overlook next time the meter is read. Not that it has any reflective spot on the dials as far as I’ve seen so far. (Any recommendations from someone with experience counting pulses on a Schlumberger R5 meter, or similar, would be great.)

Second difference is that I’d like to go wireless, and if possible avoid needing an arduino. The gas meter is pretty much outside the other side of the house to my home server, with no power supply. So a wireless transmitter, like the one attached to the electricity cable, would be great. It just so happens I have one of those as well now- handy!

Thirdly, having a single display with all the meter readings on has to be the smart thing to do. The display I already have, and the one which will pick up signals from that transmitter, is the Current Cost. Perfect if I didn’t want a server running to connect up to Pachube/the internet, and also perfect if it’s already connected.

So all I need to do is:

  • decide how to read pulses on the gas meter (peel off that cover, or come up with some Heath Robinson alternative)
  • count the pulses and produce a pulse for the Current Cost transmitter development kit at the appropriate increments
  • find out how to pair the transmitter as a gas channel, instead of an appliance channel (if that’s possible)
  • use some gas

Update: after a bit more investigating I think I’ll be using the socket on the gas meter; I’m hopeful a repurposed spare cable from one of the many modems TalkTalk sent will do the trick. I was also wondering about simplifying the gas meter monitor to just register when I’m using gas, rather than worry about the rate. Some sort of 555 timer based circuit to keep the Current Cost dev board input 2 on between pulses maybe? The only thing that runs on gas is the boiler, so a simple on/off signal should be good enough to work out what I’m using. Dale’s recent roundup of HomeCamp 2 has some tantalizing hints of gas monitoring as well. (22 May 2009)

The IET gets sociable

April 28, 2009 at 22:05 | In Uncategorized | Leave a Comment
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I recently read Yes, we can twitter while catching up on some E&T reading. Probably the most interesting bit for me was seeing @TheIET is also on twitter, so I tore off the bottom of the page with the link on to check out. Web 0.1 bookmarking then; I still like reading on paper.

The IET twitter account doesn’t look like it’s progressed beyond getting their brand on there; they don’t follow anyone, have a surprisingly small 168 followers and don’t seem to be talking to anyone. Still, hopefully it’s just a small beginning and, amongst the links to their web site, I did spot a press release about the launch of the new IET social networking site! That news somehow passed me by until now, so I’ve been investigating to see what it offers. To start with, I have yet another profile, which is not a big surprise. Earlier today I was scratching my head over a spiced up developerWorks profile. It has a bookmarking service which, for anyone in the IET new to such things is great. While I already use delicious for my own bookmarks, IET Discover combines bookmarks with groups, in what looks quite a similar way to Lotus Connections. There’s already a good selection of groups, although I’ve not found any that appear that active yet. Groups have always been a bit of a mystery to me in things like Facebook, never quite fulfilling their apparent potential, mostly ending up little more than a way to tag yourself as being interested in something.

Talking of tagging, from what I can tell on first look, I can tag my own profile, but other people can’t tag me, which seems like a missed opportunity. I think there’s much more value in tagging other people. In networks where you can tag yourself, I tend to have a poor attempt to start with, and then never return to keep the tags up-to-date.

And finally, I can watch people… except so far I’ve not found anyone to watch. I’m guessing it’s much like adding people to your delicious network.

Overall, it’s an interesting foray into the world of social networking. Like LinkedIn, it has a more professional focus, but it feels more limited by association with a single professional body. With recent homecamp, arduino and related projects in mind, I joined the electronic circuits group, but there are already more established social networks around those topics, whether IET members or not. Having said that, I think there is a place for more focused social networks. For example, I’m a big fan of developerWorks, where I’ve been trying to get some momentum for a community around the MDM Workbench, which is after all a pretty niche topic. So IET Discover looks interesting, and it has the potential to get me more involved in the IET. Time will tell how it turns out… maybe @TheIET will share their view…

Home Easy page on Arduino Playground

February 13, 2009 at 00:23 | In Ones and Zeros | 10 Comments
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Largely thanks to @barnybug, the Home Easy Arduino hacking has been going really well. Making an LED blink is one thing, but making it blink by pressing a button the other side of the house is quite another! I’ve currently just been receiving signals, but when I’ve got the transmitter going as well, I want to do things like only relaying an on command to the socket if the current energy use isn’t too high. (Would be nice to have that working in time for Home Camp, but no promises.)

Should anyone else want to get going with some Home Easy hacking as well, I’ve created a Home Easy page on the Arduino wiki. So far it’s mostly just the sketches from Barnaby but I’m working on using interrupts instead, with the eventual aim of creating a Home Easy library for the Arduino. (There’s a Google code project for many RF protocols at once, but I just have Home Easy.)

Here’s what I have for receiving a Home Easy message with interupts so far which, with some even messier code, seems to do the trick. I would like to be able to register functions to call for specified controller/device codes, but not looked in to how that would work yet.

ISR(TIMER1_CAPT_vect) {
unsigned int pulse_width = ICR1;

if( !bit_is_set(TCCR1B ,ICES1)) { // falling edge was detected
// start over if the high pulse was out of range
if(pulse_width < min_high_width || pulse_width > max_high_width)
{
pulse_count = 0;
}
// don’t need to do anything with high pulses as long
// as they’re ok; should all be the same width
}
else { // raising edge was detected
// start over if the low pulse was out of range
if(pulse_width < min_low_width || pulse_width > max_low_width)
{
pulse_count = 0;
} else {
if(pulse_count < max_low_pulses) {
rx_wire_bits[pulse_count++] = pulse_width > bit1_low_detect ? 1 : 0;

if(pulse_count == max_low_pulses) {
message_received = receiveMsg();
pulse_count = 0;
}
}
}
}

// reset the counter
TCNT1 = 0;

// toggle bit value to trigger on the other edge
TCCR1B ^= _BV(ICES1);
}

Pachube and Yahoo Pipes part 1: show me the data

December 5, 2008 at 00:04 | In Ones and Zeros, Uncategorized | 3 Comments
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I’ve just been playing around with Yahoo Pipes for the first time in ages to see if it might be useful in mangling data feeds from Pachube. (Would have been useful to have tried this out before homecamp but never mind!) Early signs looked good- falling off a log looks difficult in comparison to getting Pachube data into a Yahoo Pipe. Having said that, finding data feeds to start working with is not so easy. If I want to start doing something with power data, I have to manually find the relevant feeds on the Pachube site with a tag search. It would be great to be able to get a feed of data feeds; that would be useful for keeping up with new data feeds that get added to Pachube as well as being a useful input to a Yahoo Pipe.

So the simple example pipe for part 1 does just this kind of aggregation except that, because it’s a hack, it only includes a specified set of feeds. The default user input list is just the feed IDs I manually copied from that tag search for ‘power’:

It should work using my API key if you don’t have one, but you’ll need your own if you clone the feed to do something more interesting.

Coming up in part 2: doing something useful with the data.

Home Camp

November 23, 2008 at 22:54 | In Ones and Zeros | Leave a Comment
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Home Camp is next weekend so I though it was about time I put something marginally less pointless on my House page; there’s now a quick summary of what I’ve played with so far, instead of the old experimental graphs that were starting to gather dust. Looking forward to getting a few more ideas to add to the list on Saturday.

Update: Unfortunately I wasn’t able to stay the whole day, although I’m very please I made it to the start and still got back in time for Howards wedding. Thanks to the internet, I’ve been catching up on what I missed. In no particular order, here’s a selection of links I’ve found interesting so far:

There’s plenty more to keep up with on the friendfeed HomeCamp room.

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