Archive for May, 2014
Two very successful days in a techie kind of way… and sorry, this one is just for techies…
One of my big bug-bears with the Ethernet/radio interface for the home controller has always been the cheap short range radios as you know if you’ve followed my blogs. The NRF24L01 boards are just crap – ok, they work but only short range – and the RF24NETWORK network is great for what it is – but it’s not a true net and there is no chance of making into a true network – you have to have a master and spider-type network with hopping nodes. Their numbers have to be predefined as the hopping sequence is limited. In addition the radios can’t send and receive at the same time so the master really has to keep control at all times of the communication sequence… AND THAT’s FINE – I have it off to an art – but if only there was something better.
Well there is – the Atmel chip range include a pair with radio built in and they’ve developed a lightweight network – but a true network where any node can step in as a relay. Problems? Getting the things, having the software, defining the interface. Well getting them was the first thing we solved, thanks to my pal buying an oven to solder the chips to the boards (impossible with a soldering iron as the pads are underneath the chip), the software we now have working, due to a sensible approach… and the interface is now cracked.
You can get samples out of Atmel and that’s just what my pal Aidan did – well both of us, allowing him to make a series of test boards up. Until this weekend that’s about as far as it went – but yesterday we managed to get the network demos up and running and there is no doubt about it, the extendable network WORKS – we made the mistake of starting with on-board chip aerials which are pretty useless but we know from the demo boards that Atmel produce that they CAN have a decent range with the right stub aerial.
We have SCOURED the web and it is full of failed projects and promises due to people going down the wrong path either hardware or software wise in producing low cost radio networks. One set of guys in Canada thought they had the solution, a little radio board with USB on it – they needed 20k funding – and only got 6k – the project stopped this time last year and even their website has disappeared. WHY? Heaven knows but I suspect the USB interface – why would you want to fasten these to your PC when you already have WIFI…. surely a simple low cost interface for hardware projects using PIC, ATMEL or other chips is the answer, something compatible with he many cheap radio boards out there but considerably better? Well we solved that one today – the SPI interface – after a several blind alleys – we got it working. Making a stand-alone radio board avoids the hurdles of making the boards work with a particular chip. The final hurdle – antenna – the chip antenna designs are useless – few feet range – so we’re going to make 2 boards, one with on-board antenna and the other with a short stub aerial – either way we expect up to 30metres range. With 2 boards you have 60 metre range etc. etc… a true network.
We tested the network by having two boards talk to each other and moving them further and further apart until they were out of range. Merely introducing a third, arbitrarily numbered board in between the two, re-instated the link – we went up to 4 boards two of which simply sat there on the floor of a large house, battery powered and we managed to triple the working distance of our boards.
Nothing more will happen before June as we need some boards with proper aerials to test and I have holidays but we’ve cracked the back of this one. An excellent way to spend the weekend.
It’s been a reasonably awful week this week. Firstly I’m in holiday mode – as we’re off to Spain next week to do some work on the cave – so I’m basically counting the days. I spent the start of the week battling with a new service provider, the one I’m using for this and other blogs. Just silly stuff like me not realising I could not add an email redirect until I’d actually set up an email account in the first place – makes sense really – but you don’t have to do that with 123-reg so I wasted a morning figuring that out.
The rest of the week was spent in FSB meetings. Tuesday morning I drove down to St Johns Hotel in Solihull – took me the better part of 5 hours as the traffic down there wasn’t too good – and what HAVE they done to the M6 down at that end? There are more bumps in the road than some of our rural roads… awful.
The hotel I have to say was about as nice as the weather – it’s a Principal Hayley hotel and the food was awful – others agreed. Thankfully at night there was a cracking Indian restaurant and a few of us spent our evenings in there. I can’t go into details in a blog but the meetings were hard – culminating in elections. I came out of it well, starting my 13th year as National IT Chairman and member of the Executive Board – not unexpected but then one should never take things for granted. Others didn’t do so well and two people I respect lost their posts.
The meetings finished yesterday afternoon and at 5pm I set off on the trip up North and stopped at the Welcome Break in Woodall which houses the slowest McDonalds on the planet. I then took a different route as I thought the A1M might be a little better than the overcrowded M6. BAD mistake – it was closed, or part of it was, so the traffic ended up being routed through a small town – thousands of vehicles – absolute nightmare.
I’d planning on spending the day here today preparing stuff for Spain but as it happened I ended up spending most of the day on conference calls or Skype, phone calls or emailing… to add to the damage, I’m involved in a European (EU) project and there is “trouble at mill” there which needed attending to – so I managed to get all of an hour or so to do my own “thing” as it were.
And to add icing to the cake, the only decent part of the trip away – the Indian restaurant saw me lose a filling so tomorrow it’s off to the dentist to get some repairs done before heading off to see a friend and his wife. That, at least should see a nice end to the week. More meetings ahead before we finally head off to the sun mid-week.
A friend of mine recently asked me to provide some information on LED STRIP and I thought I’d put a quick blog item together as the subject is likely to be of interest.
“LED STRIP” is a name widely given to a product which is becoming increasingly important. As filament lamps are (thankfully) slowly being resigned to history, CLF (compact fluorescents) took over some years ago but there are a few problems with these lights also.
CFLs are the most abysmal colour but let me explain “colour” first for those raised in art class:
As far as light is concerned there is no such thing as white… white light is a combination of various wavelengths of light – and a commonly used method to minimise the complexity of this is to explain that you can make any colour of light with a combination of RED, GREEN and BLUE. Why not treat yellow as a “primary” colour as with paints? Well that’s because paints are different, mixing two colours makes a DARKER, not LIGHTER colour – it’s called subtraction, suffice it to say that a modern TV can show pretty much any colour – and they ALL come from a combination of red, green and blue. Red+green makes yellow, red+blue makes purple, blue+green makes cyan, all three with care make white – simple as that.
Another way to get “white” light is to generate another colour, let’s say ultra-violet (which is the far end of Blue, generally you can’t see ultraviolet at all well if at all) but use a powder that reacts to that and generates white light – that’s generally called a phosphor and that’s how CFLs work. You have a gas in a tube – you put electricity through it – generates UV – and a white powder on the inside of the tube glows WHITE.
Or kind of – the white you get out of CFLs is AWFUL. What do I mean by WHITE? Well, filament (old-school) lamps generate light by heating a wire. Essentially that generally gives a very bright yellow-ish light – you don’t notice this when you are in it – but try looking through a window from the outside where they have old-school lights – it’s yellow-ish. Then there are “daylight” lamps- these tend to be white with a hint of blue…. recall that in the evening sun, our atmosphere absorbs all but the red end so everything looks orange to red… (unless you live in England in which case the evenings are generally GREY). In the morning there is far more blue in the light – hence the term “daylight” to describe lights which veer to that end of the spectrum. Candles give off a light that is nearer to orange than to white.
Commonly available CFLs come in either “warm” or “daylight” varieties – Chinese manufacturers refer to “degrees Kelvin” to describe the colour – which is about as much use as an ashtray on a motorcycle, to the layman. 6500K is COLD or daylight….5000k is more like a fluorescent tube, 2700k is more toward orange and is your typical incandescent light. A match might be nearer 1700k. Simple – but not a lot of use in the supermarket.
Ok, so filament lights are old-school, inefficient but considered a “nice” colour. Xenon arc lamps as found on up-market cars are cold, clean light and CFLs are just, well, naff, really.
The CFL took off partly because at first, there was this thing about being “green” combined with the fact that everyone DISCOUNTED them – so for a while it was not unusual to see supermarkets selling them for under £1 – certainly we kitted out the entire house and no doubt saved a FORTUNE in electricity. The promise was that they’d last a long time – they do unless you buy them in Spanish supermarkets in which case they’re as likely to blow up or fall to bits on first use.
But now that the grants and discounts are all gone, your humble house light has gone back to to £2-5 quid – so the magic has gone and they’ve still never really solved the boring colour problem.
And so along came LED (light emitting diode). Everyone knows the phrase but what does it actually mean? Well, instead of heating up a wire or exciting a gas, the technology behind LEDS involves getting a piece of silicon to convert electricity directly to light! Not very efficiently I might add – but good enough.
LEDS appeared late last century… I saw my first LED on a Bond movie in a watch – I was so blown away I went straight out and blow all my money on a LED watch. In fact, the basics were sorted as far back as 1907 with the first practical devices appearing in the 1960s. You had a choice of RED, RED or RED.
What you don’t have, you seek and as variations appeared, puke yellow, gross green etc., what we all wanted was BLUE… and then at the very back end of the 20th century after much research we started to see the full range of colours – even purple – and WHITE. LEDs had an issue however, not that efficient, bright enough but as individual LEDS not really bright enough to light up the house.
Remember when electric motors were the poor relatives of the powerful petrol engine? All of that his history now as fans of the TESLA motor car will tell you – and so it is with LEDS – but BEWARE.
The first practical replacements for house lighting came in the form of GU10 and similar clusters of LEDs – maybe 20 to 40 LEDS crammed into a conventional light fitting. FORGET them – utterly useless – what LEDS hate the most is heat. Lamp manufacturers are prone to blindly copy the LED spec sheet claiming countless thousands of hours of life. Well, it’s bollocks. Heat them up, overpower them or any combination and you’re down to weeks or months never mind years. A trip to B&Q will confirm that –check out their overhead LED displays in the lighting section and you’ll find those particular types of light will invariably have several bust lamps amongst their midst.
Next came the new super high power leds – where one or 3 leds would do the job. These are current and are very good (notice the heatsink).. but like all lights follow a model of lighting that’s been around since the candle – the point source. Also these LEDS are STILL not immune to packing in – the light is still concentrated all in one place. Only the long fluorescent tube up to now has broken that mold – but today – it’s all change!
SURFACE MOUNT is a means of compacting electronic components – and you see this in almost all of today’s circuit boards instead of components with leads which need complex assembly we have little rectangle with solder blobs on each end. They are positioned along with solder paste onto a board – the whole lot is put in an oven in which the solder melts and forms connections – and Bob’s your uncle – easy to make, tiny circuits.
LEDS are available as surface-mount blocks and they are CHEAP – and the first use of this came in again GU10 and similar lights, instead of using 40 original LEDS with the associated heat issues and mounting problems, the LEDS could be mounted on a round plate with metal underneath, compacting the size (up to 60 SMT LEDS) and distributing the heat – problem solved. But a BETTER solution is emerging – that of LED STRIPS.
Remember the old 1/4” TAPES before we had compact cassettes. Well, LED STRIP comes on reels like the old tape – but this stuff is made out of a material that supports flexible copper sheet as wiring and surface mount LEDS – typically one LED every couple of centimetres, LED strip typically works on 12v DC (not mains). they are mounted on the strip along with an adhesive backing – and you can cut the strip into combinations of 3 LEDS – i.e. 3, 6, 9, 12 etc. That is because the LEDS work on around 3v (varies) – they mount 3 in series (i.e. head to toe) and use a tiny resistor to stop them blowing up so you can get away with feeding them 12-14 volts You can use strips as long as you like, the only limits being the amount of electricity the copper strip will support without loss over great lengths – and how much current you can get out of a 12v power supply.
Typically you might see a 5metre length of LED strip – powered from a 2 amp 12 volt supply. You can get red, green, yellow, orange, purple, blue, cool white and warm white – there are more variations but this covers the bulk.
But you need to know more in order to make a sensible purchase.
So you can put these strips simply in places that other lights can’t go – in cabinets where there isn’t ROOM for other forms of lighting – or areas where 240v would be unsafe. You can get straight-forward LED strip where the elements are exposed – or you can get a gel-covered version which is WATERPROOF.
You can also get various forms of RSB LED, the simplest has in it’s group of 3 LEDS, a RED, GREEN and BLUE led…. one after another – i.e. R G B R G B etc. There are also TWO sizes of LED which means in a 5 metre roll you might have a total of 300 LEDS – or in the more expensive versions up to 600 LEDS in the same space (the smaller ones are not as bright individually but with twice as many lights they ultimately win on outright brilliance).
That’s great so now you can make any colour including WHITE… erm… no. LEDs that well spaced will NEVER produce white – they produce a disco light with RED, GREEN and BLUE.
What’s needed is a chip with all 3 elements inside right next to each other – and that’s what the latest LED strip has. So now you can have all the colours including WHITE – not only that but with care you can achieve ANY colour temperature of WHITE, from candle all the way to that cold, blue-ish light we call “daylight”.
But now there is something new and exciting – a new form of these chips means they have not only power and ground (and these run on 5v, not 12v and they run individually, not in groups of 3) but also a “serial” input and “serial” output – i.e. 2 more leads… the first in the chain takes an instruction from a controller to tell it what colour and what brilliance to output. Subsequent instructions are simply passed onto the next LED in the chain.
So now it is possible to have a length of LED strip where EACH LIGHT is individually controllable at high speed. Been to an airport recently? Seen the HUGE full colour TV shop displays? Take a close look – each point of light in the very latest ones is a little white chip capable of any colour, any brilliance right up to painfully bright.
This then is the state of the art in LED lighting – strip that can be any colour you like, any brilliance within reason and can even change from one end to the other, producing soft, undulating colour rainbows that are quite hypnotic.
Is it cheap? No. Are current controllers up the mark? No – so this latest form of LED lighting is for the specialist only right now but it’s there – on EBAY if you are up to it.
Stepping back a little, RGB LED strip and single colour strip that WORKS RELIABLY and is inexpensive is there for the taking.
Unless, that is, you are in rip-off Britain and still shop retail for this stuff. Maplins the other day were selling a 5 metre roll plus simple infra-red remote controller – of an older version of the LEDS for a mere £39 – all you need is a power supply which they’ll happily sell you for a tenner no doubt bringing the total cost for 5 metres of lighting to £50.
And what’s wrong with that? Ebay will tell you that. You SHOULD be paying around 1/3rd of that. A single colour strip with power supply for a tenner, a colour strip plus controller for under £20 tops.
There are various buzz-terms around which make things difficult to understand. 5050, 3528 etc… well 5050 LED strip generally has 300 LEDS per 5m length, the smaller 3528 LEDS manage 600 per strip (if stated) – simple as that.
Adhesive – most quote 3M adhesive as if that was a mark of quality. My experience suggests that ANY dirt on the mounting surface or any irregularities – and the stuff won’t stick for long – also warm surfaces… best plan your own mounting method. I generally at least staple the ends (careful you don’t cause a short – this is easier on the gel-coated variety) or find some other way to secure the tape.
Control can be via the controllers they sell = any colour but only 256 combinations so the colour changes are a bit crude - if you expect however a super-smooth transition or brightness change – forget it – with only 256 steps your eyes can tell the change – I’ve no recommendations here as I do my own thing – but if you see a controller offering 16-bit (65k) levels of control – that’ll do the job.
The rest is down to imagination – now you know where to look (EBAY – look up “led strip” – most definitely NOT B&Q) you can have any colour combination – and light anywhere you like. I put a red strip around the doorframe of our front door – looks like a portal off Star Trek – in all the time it’s been up (maybe 2 years) no loss of brilliance – no duff leds. I put white strip on the underside of the roof of the garden hut – 4 years later – still working perfectly – not one single dead light.
I’m not NORMALLY prone to promoting particular brands – well, why should I? I don’t get paid… but in this case I’m going to make an exception – and I must clarify – this is purely for your information – I am NOT getting any benefit out of this nor do I even know the manufacturers.
I’m 60 and I’ve had cats all my life – I find them great companions and our two gingers are basically part of the family, they sleep with us (in shifts at the bottom of the bed for clarification) and spend their time when not chasing birds, in a corner always near where we are. They don’t smell, they don’t “have accidents” and they don’t need maintenance – just food, water and attention when you can be bothered. In return they give a LOT of affection – a good deal all around.
Our two “never” have accidents (I did forget about them once and lock them in the office for 48 hours – well, you can’t blame them, one came out cross-legged, the other didn’t) however cats don’t last forever and we now have a new ginger kitten – who is most adorable on the one hand, but on the other has to be the most efficient machine for producing “waste matter” (don’t want to put you off your breakfast) ON THE PLANET. He has come THAT far off being strangled a few times and I’v thought of some creative uses for corks but not implemented them. He is out and about now, having had “the chop” but until then he had to stay in the house and BOY could he make a mess.
Animal mess is something I find HIGHLY offensive and I can categorically say that every remedy I’ve seen on the web FAILS. People suggest vinegar and all other kinds of solutions that smell worse than the original problem – there are products all over the place and to the last one – all they do is mask the problem AT BEST.
Well, with the exception of one. Some time ago, Maureen found the product you see above – Simple Solution Stain + Odour Remover – an American product by the look of it – but available over here in the UK (see link later on) In desperation we gave it a shot. It works.
I could stop there really – it absolutely works. The general advice on the container is simply to clean up the mess and pour this stuff all over the location, be it carpet, tiles or whatever, leave for a while and mop up. Two things wrong with that scenario – mopping up might not be that easy and pouring it all over ensures your expensive and large container doesn’t last long not to mention rotting the floor underneath if it’s wood.
So with that in mind, a week ago I happened to have an empty hand-spray weed killer plastic bottle and filled it with the stuff.
Put it in a convenient spot and never thought any more about it until the other day I left my office door open – I do that as I get sick of the cats begging to be in – they have a tendency to do shift work coming in and out of the office for several hours at a time.The kitten who’s just been allowed out rushed in, found a corner full of cables and made the biggest mess you can imagine – GROSS. Well, after grabbing kitchen roll, convincing myself not to throw up and cleaning up as best I could, I was left with an office with un-breathable air. NOT happy. I did consider at that point drowning him but Maureen would never have forgiven me. After a few less destructive thoughts, like dropping him off in the next village, I decided to give the spray bottle a go. I simply drenched the area with fine spray – and went off to bed for the night, convinced I’d have to pull the workshop area apart even though I’d done a good clean up job.
The next morning – NOTHING – if anything a very slight odour from the cleaner – which is actually a kind of “spring fresh” smell – it’s actually quite nice. ABSOLUTELY no sign of anything visually or odour-wise and certainly nothing you would attribute to an animal.
The stuff REALLY works – I don’t know how it works – but it does. Similarly the little devil stained the carpet at one point – now that is REALLY a problem as it gets into the under-carpet and everything and basically you’re normally talking “carpet replacement”. Again, a good soaking, this time blotting up after a while – again – UTTERLY SORTED.
It is very rarely that I rave about products – but I’m sold on this stuff – if you have cats it could be a LIFE-SAVER.. well, you know what I mean.
There are variations – one with a dog on it – I have NO idea if it’s the same – and there are various size – we bought the 4 litre version… a quick Google failed to turn up the 4 litre version but I found this –
It’s the smaller spray version and definitely the same product we bought. If you have a cat and this is of interest – ENJOY! Life just got a lot easier.