A possible solution to slow or unresponsive Hue lights

They used to say that there are two ‘internet of things’ systems that ‘just work’ out of the box: the Sonos sound system, and Philips Hue lighting. I’m fortunate enough to own both of them, and I would add the Honeywell Evohome heating system (though one of my friends has had a few complications with an unusually large installation).

When we moved house recently, though, my previously-faultless Hue system seemed to become a bit less reliable. Admittedly, we have rather more bulbs now (33 and counting), but that’s nowhere close to the limit it can handle. Our bulbs are always powered, so the cunning mesh networking should make sure that nothing is out of signal range. Yet sometimes lights weren’t obeying their commands promptly, switch presses needed to be repeated, and things generally seemed, well, a bit sluggish. I was beginning to think it might be time to wipe the configuration off my bridge and start again from scratch. It probably does have a lot of accumulated junk on there…

And then I did a little research and realised something that I should have thought about earlier.

Zigbee (the wireless networking used by Hue and a variety of other systems) runs at approx 2.4Ghz: the same frequency range as Wifi. Like Wifi, it has a number of channels, and if your wifi router and your Zigbee hub have overlapping channels, they can interfere with each other. I found this useful diagram online (apologies for not knowing its creator):

‘802.11b/g’, in case you don’t know it, is part of the technical standard popularly known as Wifi, so the green labels show Wifi channels, and the blue bars show Zigbee.

The number and availability of channels vary depending on your country, but they will be similar to the above. Although Wifi has about a dozen channels, the nearby ones overlap substantially, so most installations only use 1, 6 or 11: if both you and your neighbour are using Wifi channel 1, you won’t make much difference by switching to 2 or 3; you need to go at least as far as 6. Go much further than 6, and you’ll start interfering with your other neighbour on channel 11. Usually, these days, wifi routers are pretty good at picking their channel by finding the least congested space, though you may need to reboot them from time to time to encourage them to do so.

Anyway, one thing that had changed in my new house was the Wifi. And when I looked, sure enough, my Wifi router was on channel 11 and my Hue hub was on a Zigbee channel that was rather too close for comfort. By going into the Hue app and looking at the settings for my Bridge, I was able to change the Zigbee channel to number 15, and things are going a lot more swimmingly now!

Hope that might help someone else…

iOS tip of the day

When you’re setting up your fingerprints for Touch ID, take the time after registering each one to go in and give it a name. Then if you find one finger becoming unreliable, you know which one to delete and reprogram.

A suggestion for 2018

Here’s my thought for the year:

It’s much more important to read things with which you disagree than to read things with which you agree.

Merry XYZmas

If, like me, you have been pondering linear algebra on a Christmas afternoon (and, frankly, who hasn’t?), or if you know anybody who is learning it for the first time, then I highly recommend Grant Sanderson’s YouTube channel, 3Blue1Brown where he makes all kinds of mathematical ideas easier to understand through some clever visualisations.

In particular, his Essence of linear algebra course is a wonderful presentation of the basics. Do you have vague memories of matrix multiplication and of phrases like ‘determinant’ and ‘eigenvector’ but have no idea why you learned them or what they did? Then this is the resource for you. Not only is it good revision, but it explains them in a different way from the way you might have learned them originally, which can help you get a better understanding than you had before.

Oh, and if linear algebra isn’t your idea of a fun way to spend Christmas, don’t worry. There’s Essence of Calculus as well.

Caian coffee

There’s a nice post about the coffee pot webcam on the Gonville & Caius College website this morning. Thanks, Lucy!

Retro Space Invaders

I think this is wonderful. Today I got to play with Gareth Bailey’s Space Invaders game – a quick hack, he claims, which he put together yesterday.

This uses an oscilloscope as an X-Y plotter to draw the graphics, harking back to the earliest days of computer displays. But historically, displays like this would usually have been driven by a mainframe, where as Gareth’s is driven by a Raspberry Pi.

And where do you get a couple of nice analog outputs from a Raspberry Pi? Why, from the left and right channels of the audio, of course….

Apologies for the quality of the video, but I thought this was worth capturing despite the challenging environment!

All you need is Lovie?

Last night we went into London because the kind people at the Lovie Awards, the European branch of the (rather better-known) Webby Awards, had been good enough to give me an award, mostly for the work that friends and I had done in creating the first webcam.

I was a bit embarrassed about this, partly because I didn’t think I deserved it, and partly because of the name, but I got over the latter, at least, when I discovered that it’s in honour of Ada Lovelace.

Anyway, the tradition is that you have to give a little speech containing the word ‘Love’. The other tradition, which nobody told me, is that the speech should be about 30 seconds, which is why I look a bit more flustered than usual here! I was trying, not very successfully, to edit my speech on the fly. But I got away with it because mine was the last award of the evening.

It was a great and responsive audience, which, sadly, you can’t hear on this video.

Computerphile

Sean Riley creates the Computerphile YouTube channel, which has clocked up nearly a million subscribers, and produces some great stuff, especially for the geeks among us.

I had fun talking to him about the early days of the Trojan Room Coffee Pot.

What 3 words?

This is a brilliant idea. Take the world and divide it into 3m squares. Then, given a modest vocabulary, you can label each square using just three words.

For example, I work half-time at ‘faced.ears.sport’, which you can find by typing it into the What3Words map at map.what3words.com, or you can turn it into a handy URL:

http://w3w.co/faced.ears.sport

Isn’t that much easier than saying ‘The south west corner of the William Gates building at 15 J J Thomson Avenue, Cambridge, CB3 9JW, UK’? Or ‘52.210577 N 0.092133 E’?

It’s even more valuable, though, in countries where addressing schemes are less well established or non-existent.

Now, it has a couple of limitations that I can see. First, you do need to be fairly precise about those words if, say, you’re reading them over the phone. If, instead of ‘faced.ears.sport’, you went to ‘face.ears.sport’, you’d find yourself in a little residential street in Montana, which would be delightful, but you wouldn’t find me there on a typical work day. ‘faced.ears.port’ is in Louisville, Kentucky. However, the fact that they’re so spread out probably makes such errors less likely to go undetected – this is deliberate.

The second limitation is that this is a commercial operation and not an open standard, which is a pity in some ways, but understandable. It’s free for individuals to use – there’s a free iOS and Android app, for example – and the pricing page contains this assertion:

If we, what3words ltd, are ever unable to maintain the what3words technology or make arrangements for it to be maintained by a third-party (with that third-party being willing to make this same commitment), then we will release our source code into the public domain. We will do this in such a way and with suitable licences and documentation to ensure that any and all users of what3words, whether they are individuals, businesses, charitable organisations, aid agencies, governments or anyone else can continue to rely on the what3words system.

I think it’s a brilliantly simple idea. The concept has been used in other situations (passwords, PIN numbers etc), but works really well here.

© Copyright Quentin Stafford-Fraser