Monday, 26 March 2012

Power Meter Accuracy - Another Update

So I've left it just under a week since JSJS Designs got back to me to say they'd updated the WiFi Link and that should make it more accurate.

Here are the results.

Over the period my proper meter states I've used 75kWh.
Over the period my LightwaveRF states I've used 69.9kWh.

So the LightwaveRF readings are now under to the tune of 6.8%.  More accurate than the measurements I took before (it was 31% over).

I will continue to monitor...

Tuesday, 20 March 2012

Power Meter Accuracy - Update

I raised a support ticket with LightwaveRF on the accuracy of the power meter. Here's the response I got, (within 12 hours so good timely responses).

Hi Paul,We released WiFiLink version 2.28 yesterday which has adjusted the way the energy monitor calculates usage. The readings are in kWh, yes. You should get better accuracy from yesterday onwards, but be aware the figure given is an only an approximation.Max is kW, whilst the Totals are in kWh.Let me know if this helps!

I did spot the upgrade to 2.28. So another round of measurements, let's see if it's more accurate now.

Monday, 19 March 2012

Power Monitor Accuracy

For the last week I've taken some measurements to see how accurate the power meter is. To do this I:

  • Took a reading from my proper electricity meter when I installed the power monitor.
  • Noted the daily measurements from the power monitor for the remainder of that day and the rest of the week.
  • A week later took another proper meter reading and noted the cumulative measurement up to that point.


My meter readings state I used 111 kWh
The power meter readings state I used 145 kWh

So a 31% error.....

I will contact LightwaveRF support as this can't be correct. Another update when I know more.....

Thursday, 15 March 2012

Feel the Power!

On Sunday I installed the LightwaveRF power meter. The picture below shows it outside it's lovely packaging. The power meter consists of two main parts. The clamp that goes around your live AC feed (on the right in the picture) and the sender unit (on the left). In simple terms the clamp measures the power usage and the sender sends the measurements to the WiFi link unit. The sender unit takes 2 AA batteries and sends a measurement every 10 seconds.
Here's a close up of the clamp. It looks to have some form of magnet inside. I'm not clamp meter expert so see Wikipedia for an explanation of how they work!

Here it is installed in my meter cupboard, clamped aroind my live AC feed. The sender unit nestles on the bottom.

To pair with the WiFi link you just put the sender into learning mode (press and hold a button) and select an option on the UI of the WiFi link. When paired you get the latest reading from the sender always shown on the WiFi link screen.

You can view the measurements on the web interface or via the handset app (example shown below):

You get:

1)Current power consumption (in kW).

2)Max usage for the past 24 hours (in kW I assume but no units shown - naughty).

3)Cumulative usage that day (in kW Hours I assume but no units shown).

4)Total usage yesterday (I assum ein kW hours).

The dial refreshes every 10 seconds or so with a bit of animation, very nice. The warning states it could be 20 secs out of date which is about right in practise. Flick the kettle on and the dial goes up to about 3.5kW within a short period of time, (off the scale of the app UI in fact which is a bit poor).

More later on the energy meter...

Tuesday, 13 March 2012

Light Switches

Late last week I set up the LightwaveRF double light switch I bought. This is the first test of whether it's easy to retrofit existing sockets and light switches with automated ones.

Here it is in it's beautiful packaging. Overall it has the same "finish" as a normal white light switch but it's operated by buttons and has indicator LEDs.

Out of the box it's a bit of a chunky monkey. The packaging says you need a minimum of a 25mm gang box but the unit itself is about 25mm deep so I don't know how that would work.

In terms of wiring it's just like a standard 2-way light switch with live, neutral and switch wire connections. Here's what I replaced:

During the operation. This gang box is for a stud wall and is about 35mm deep. This gives enough room for the switch itself and the feed in cable behind.

After (but without the face plate on). The blue LEDs are for when the lights are switched on. One thing I noticed is that it didn't work with standard CFLs, (they just flickered constantly no-matter whether the light was off or on). When I used standard filament bulbs it worked OK.

After, with the face plate on. The LEDs show the lights are switched off.

You can manually control the switch simply by pressing the top button (on) or bottom button (off). The light switches on and off in a pleasant "soft start" manner. Pressing and holding the buttons allows you to dim/un-dim.

The switch is put into pairing mode by pressing and holding both the buttons. You then pair by pressing "on" on either a remote control via the web interface or device app. Then via the web/app you can switch off and on, dim or lock/unlock a switch.

So overall this seems quite useful. I can switch a light on when I'm away from home or set a timer to control it (see later post). However the main point is that you can replace sockets and lights with these units but you do require a deep gang box. Perhaps a little more miniaturisation is required before they become mass market.

Monday, 12 March 2012

Going Mobile

One of the big selling points of the WiFi link box (see previous post) is that you can control it remotely with a Smartphone. Hilariously there's a picture of an iPhone on the WiFi Link box and then a statement along the lines of "doesn't include an iPhone" in small print.

I've an HTC Desire HTC (Android Gingerbread) so went to the Google Play Shop (was Market) to find and download the app. Easily found and installed (although the 2* rating didn't give me me much hope that it would be any good).

You run the app and log in with the email address and PIN you use to register via a web browser (see previous post). Again it's very dodgy from a security point of view with the PIN showed in clear.

Here's the main menu which shows the room structure that I previously set up via the web interface. Must be downloading it from the same place. The layout of the app is very poor with labels too big for buttons and in some places navigation buttons partially hidden behind other controls.

Click in to a room and you can see the devices you've set up in that room. Here are the buttons for 2 lights I've set up (wait for a later post on this). A "feature" of the app is that the only button that actually works is the top left one. None of the others actually function properly!

Click a device and you get the option to switch it off and on. This works a treat. I've not tried the lock and unlock buttons but these are intended to lock the devices (e.g. to stop children switching stuff off).

When you switch something off and on you get a confirmation message such as that below. Tells you it's worked but it's a bit geeky/techie, (good for the likes of me but perhaps not for the general populace).

I mainly tried this walking around my house but didn't have WiFi on so it was definitely using the mobile internet via my mobile provider (Vodafone). I did switch a light on when I was out and about and it was still on when I came home!

So this really shows how someone can control all their electrical equipment when they're out and about.

Sunday, 11 March 2012

The Brains of the Outfit

Earlier this week I started using the LightwaveRF "Wifi Link". This can be used to automate the control of the various sockets and switches via the internet or a smartphone.

Here's a couple of pictures. Firstly in it's fancy box:

Unboxed. Here you can see the unit itself, the power supply and the stubby Ethernet cable it comes with:

Setup is pretty simple. After connecting to a spare port on my broadband router, I powered the WiFi link on. It went through some form of startup routing (visible on the small screen), showing the local IP address on the screen, checking/flashing the firmware and then setting the date and time. Presumably at some point it made contact with a central server to register that it had been powered on. Here's a shot of it going through the startup sequence:

The next step was to communicate with itvia the internet. Using a browser session I went to Here I registered an account using an email (which I didn't have to prove ownership of) and a 4 digit PIN. The PIN was shown in clear on the browser screen so security is pretty poor. Here's an example with ficticious data:

Locating the WiFi Link unit and registering for web control is better than the log in experience. On the web you enter the MAC address of the WiFi link, their server then pushes a 4 digit PIN on to the actual unit. After reading this off the screen you then put it back into the browser and registration is complete. Presumably the WiFi link published it's MAC address to the central server which links it to the IP address of your broadband line.

Using the website you can start entering details of the other kit you've got set up in your home. You specify rooms names (e.g. "Study") and device names (e.g. "Dehumidifier"). Here's an example:

You then put the actual device in learning mode (see previous post), press the on button on the web interface and pairing occurs. So it seems the flow is:

  • Web browser to LightwaveRF server.

  • LightwaveRF web server to WiFi link unit in your house.

  • WiFi link unit to the actual device (using the proprietary RF protocol).
One thing to be investigated is how the server communicates with the WiFi link box. My broadband router is set up to not accept incoming connections. Puzzling, will be investigated...

The final point is on the name of the WiFi link. From what I can see it does not using WiFi at all, (i.e. 802.11b,g or n). Is it legal to call it WiFi when it's clearly not??

Friday, 9 March 2012

First Foray - Socket Adapters

Today I unboxed my LightwaveRF socket adapters. In simple terms, they fit into a standard mains socket and you plug your electrical appliance into them. You can then turn the appliance off and on remotely.

Here's one of them with my kettle plugged in to it:

The adaptor is the rectangular item with the kettle plugged into it. You can just about make out the blue LED on the bottom right of the adapter which means it's switched on, (it goes amber when it's off).

Also shown on the picture is the RF remote control. This has 4 pairs of on-off buttons plus a 4 way switch. So overall the remote can control 16 different devices (so effectively 4 on-off buttons for each switch position).

The remote and the adaptor have 433.92MHz marked on them which is the frequency that the LightWaveRF kit works in. A quick check on the internet indicates that the LightWaveRF kit works on some form of proprietary protocol within an unlicensed band.

There's a small orange switch on the side of the adapter that can be used to manually switch it off and on. Press and hold this switch and it goes into "Learning" mode. Press an on button on the remote and you've paired the remote to that socket adapter.

The fact that the remote control works on a radio frequency means I can operate the socket from anywhere in my house, (I did test this!).

Hence I could set up my first experiment. Before bed I:

  • Switched the main built in socket on.

  • Switched the LightWaveRF socket adapter OFF.

  • Part filled the kettle and switched it on.

Then went to bed with the remote left by the bed.

Next morning, when I woke up, I used the remote to switch the kettle on from upstairs. Hence when I got downstairs the kettle was boiled and I could make tea in double quick time. (Saving all of two minutes - a great improvement in efficiency!).

Thursday, 8 March 2012

The Kit Arrives

Much excitement, the LightwaveRF kit arrived on Tuesday. Here's a picture:

Clockwise from top right is:

Very posh packaging. Mini magnets in the front flat, pull it open to reveal the unit within. Very aspirational.

Home Automation - The Challenge

The conversation went something like this:

Me:"Smart Grid will all utility companies to control the electrical equipment in your house to manage demand".

Someone else:"But how will they turn stuff off and on without re-wiring your house. People won't want to do that".

Me:"Not sure".

Someone else:"There's Home Automation kit on the market that can do that, go and find out some more about that". that's the challenge for me....

So what's home automation? Think automatic control of lightswitches and socket via remote controls, computers and smartphone apps.

A bit of research led me to the website of LightWaveRF, a UK based company who develop and sell Home Automation kit. Their website is:

Just to try out the kit I bought:

-An energy meter.

-A single mains socket.

-A twin light switch / dimmer.

-Some socket adapters that come with a remote control.

-A wireless control unit that links to a computer.

All available from B&Q so it's mainstream stuff. I bought from Amazon as the B&Q website was so utterly rubbish.