Open Source Electronic Design Contributors Wanted! - Page 1
Forum section: electronics / projects

author: stuartiannaylor
author_rank: Newbie
timestamp: April 09, 2010, 11:57:52 am
content: OK there is a huge need for intelligent lighting control. Most residential systems have singular central light fixtures purely because room layout changes over time. The introduction of many individually controllable light sources allows rooms to change whilst retaining the benefits of task lighting (having light where you need it).I am an automation engineer and my electronics knowledge in terms of design is a HNC in electronic engineering. The problem is apart from college 20 years ago I have had no need to go to circuit level. Software and protocols yes but power electronics maybe if I could remember.So apologies folks about my descriptions as I know I am ropey.What I am looking at is providing the lowest cost, fit for purpose lighting control network. The design goal is to make the luminaire the lowest cost possible as the higher the density the more localised light can be used. When I say luminaire I have no interest in making OEM light fixtures. Purely to publish a working system that demonstrates a master slave lighting network.This the sort of thing where you can set up zones of light. When you are reading, intense light is where you require. You want to set the room to TV view mode then each luminaire can be controlled. When you walk through a room, light automatically comes on at a walk through level and position. Its all very simple sensors but the main thing is to have a density of individual luminaires to allow this but also to be able to adapt to changes of taste and room orientation.What I have been looking at is by the time you employ technologies such as HomePlug, Wifi or ZigBee at the densities required to make a flexible system the costs start to get very high.I am aiming at making a network addressable LED 3 watt boost converter for a couple of dollars the magic figure being 2$.I think it can be done, in fact I am pretty sure it can be done. I am really struggling in a few key area's and would really appreciate some help.Stuart

author: logictom
author_rank: Unknown
timestamp: April 09, 2010, 03:26:36 pm
content: Can I ask why you want to do this? Even at $2 how many are you going to need to light a usual sized room and have the 'zones' for reading/tv/etc?Also why would someone go to the trouble of installing so many lights when they can just have a standard centered light and lamps?Sounds like an interesting project and I'm all for home automation, I'm just interested in the why

author: stuartiannaylor
author_rank: Newbie
timestamp: April 09, 2010, 08:33:55 pm
content: The main aspect is efficiency, also you get the coolness of architectural lighting.Light diminishes as the reciprocal of the distance travelled. In lumens 2 foot = 1/2, 3 foot = 1/3 .... 6 foot = 1/6.It is just really inefficient to have centralised fixtures. The main reason for centralised fixtures is due to old wiring infrastructure and the inability to move it round.25% of your home energy usage is lighting, commercial buildings it is closer to 60%.Its a fusion of the most efficient green system representing modern architectural lighting schemes with cutting edge lighting technology.

author: Simon
author_rank: Unknown
timestamp: April 10, 2010, 05:35:32 pm
content: Quote from: stuartiannaylor on April 09, 2010, 08:33:55 pmyou post comes at a good time for me, I'm about to move and was considring setting up my own led light system, I had not considered individual control of lights (I suppose 1 per corner) but you idea sounds good. I'm still yet to give this project some thought as I'm still thinking up the most efficient way to control the leds (just taking my bike torch apart now with a 1 W lwd to see how they did it)

author: Zad
author_rank: Super Contributor
timestamp: April 10, 2010, 09:26:02 pm
content: Before you make any further calculations, be aware that light does not drop off linearly, but as the inverse of thesquareof the distance. If 1m = 1 lumen, 2m = 1/4 lumen, 3m = 1/9 lumen.RF systems like Bluetooth, Zigbee, Wifi are all going to be susceptible to noise (both mains-borne and in-band noise from PCs, mobile phones, printers etc in the office) and prone to hacking. Look at one of the existing industry standards like X10http://en.wikipedia.org/wiki/X10_%28industry_standard%29

author: stuartiannaylor
author_rank: Newbie
timestamp: April 10, 2010, 10:06:31 pm
content: I read a few of the replies and it is slightly tangential to what I am trying to achieve.If anyone is going to try and provide an energy efficient intelligent lighting system, tell me what your trying to do and I will try my best.When it comes to lighting control the main two systems are DMX or Dali. X10 works really well and is a home automation protocol. DMX has its roots it stage lighting and DALI is a building management system. X-10 has a really slow baud rate and an really low node count. They can all do the job DMX and DALI need wiring, X-10 is a power line comms protocol but is fairly limited.If you go on the Microchip site and search the app notes you can get an excellent start into any of those.As said there are problems with RF products in terms of security and I did read an article that many devices in close proximity can produce a swamping effect. Future electronics have an excellent amount of stock from buck controllers, light engines and lens. I also remember they recently illuminated there UK head office to illustrate LED technology. The cut short at completely going down the solid state root and I think this hints at the expense of a off the shelf RF solution.If you wanted to go the DIY root have a look at the maxim site as they has a great range of LED controllers.Again microchip have some app notes for buck, boost and sepic constant current converters.If you want to go down the energy efficient lighting root you don't have to go solid state. There are problems here as there are some super CFL's but you can't dim them. There are versions that you can but again the cost goes up. I can't remember how efficient CFL dimming techniques are. LED dimming methods are 100% efficient.

author: Simon
author_rank: Unknown
timestamp: April 10, 2010, 10:18:21 pm
content: Quote from: stuartiannaylor on April 10, 2010, 10:06:31 pmthat depends on how you look at it, ordinary 100 % output of a led requires control circuitry that will have losses and dimming the led will require the same circuitry with the same losses so in a way you are right but it applies to leds only because they need regulating anyhow which losses power

author: stuartiannaylor
author_rank: Newbie
timestamp: April 11, 2010, 01:56:46 am
content: Simon is right and I should of worded it in a better fashion.The most efficient way to drive LED's has the advantage that it's dimming methods incur no further losses.I am not sure you can say this about fluorescents. My memory is terrible but if someone can post a link please do. I seem to remember the reduction in lumen's whilst dimming fluorescents doesn't keep in line with energy usage. Another problem with dimming fluorescents is that unless you burn them in before dimming methods are used they have a bad habit of failing.Fluorescents are a good energy saving device. Solid state have many advantages though.

author: Simon
author_rank: Unknown
timestamp: April 11, 2010, 07:16:13 am
content: well if your designing this system for led lighting then maybe traditional control methods like X10 are not worth bothering about as you will be working on a low DC voltage system I guess, or maybe not ?

author: stuartiannaylor
author_rank: Newbie
timestamp: April 12, 2010, 02:16:03 am
content: Quote from: Simon on April 11, 2010, 07:16:13 amI have a rough design in mind and I am struggling in a key area. I could really do with some help on the power electronics SMPS side.I will be setting up a website soon where the contributors have an equal share of the project dependent on input and quality of input. I has also been posting onhttp://afrotechmods.comto try and get interested parties which seems to be turning into a political debate on the idea of open source hardware.I have left the idea's open but the criteria is to start the ball rolling and for comparison is to make a $2 network slave node 3 watt boost controller. That is a real challenge in itself. The design spec is completely open.X-10 I would say doesn't have a sufficient baud rate. Even for small node qty's X-10 would be visible in terms of a control delay. It also has serious security issues and neighbouring (X-10) installations can cause interference. It has 16 House code and 16 Unit codes which gives 256 devices which covers most installs but not all.A faster meaner X-10 could be the solution or even part of it.

author: Simon
author_rank: Unknown
timestamp: April 12, 2010, 06:36:40 am
content: well the power control side of it is fairly easy, microchip have an application note on using a pic to control the brightness of a led and they get away with just an inductor, they made quite a fancy thing of it with push buttons for brightness levels etc but the basic idea can be adapted. I'll have to see if I can find it again. if your working over a DC supply line then sureley you can send comands rather quikly as all you need is a highpass filter to extract the data from the power line ?

author: badSCR
author_rank: Contributor
timestamp: April 12, 2010, 11:55:29 pm
content: Wireless is vary nice and easier to deploy but adds to the cost.Why not hardware them; Have a serial bus topology, run a cat5 (data only) cable to each light. like RS-485

author: stuartiannaylor
author_rank: Newbie
timestamp: April 13, 2010, 12:24:20 am
content: I am setting up a collaborative websitewww.osese.org(Open Source Energy Saving Electronics). Couple of weeks and it will be. I will publish a full design spec and hopefully that will get the ball rolling.

author: ronv
author_rank: Newbie
timestamp: May 05, 2010, 03:39:58 am
content: A few questions an perhaps a idea or 2.I assume something or someone tells the system what to do. So I envision a little box with the somethings in it and some buttons for the someone to push. If this is kind of correct i would think you might need a box for each room? If so might I offer up an IR transmitter and receiver similar to a tv remote.Would you run line voltage to each lamp or low voltage dc. The dc might be the easiest to control and cheaper to control than to produce and control at each light.If you can get me going down the right path i might be able to build you a prototype or two.

author: safarir
author_rank: Regular Contributor
timestamp: May 05, 2010, 04:08:28 am
content: What about insteon ? X-10 compatible, more fast and they add wireless redondancehttp://en.wikipedia.org/wiki/INSTEONhttp://www.insteon.net/pdf/Insteonwtpaper.pdf(Sorry again for my bad english)

author: Simon
author_rank: Unknown
timestamp: May 05, 2010, 06:55:10 am
content: if a whole house was coverted to LED lighting then you could probably convert the whole electrical system for the lights (assuming seperate wiring for the lights like in the UK) to DC 12 or 24 volts depending on power requirements

author: Pyr0Beast
author_rank: Contributor
timestamp: May 06, 2010, 11:24:58 am
content: QuoteFor 2$ all you are gonna get is a linear current limit. Forget about being efficient with that.Perhaps 10-20 times as much if you want it to be 'smart'.LED Light modules can cost from 500EUR upwards.QuoteWhy inefficient ?10x200 lumens is the same as 2000 lumens that spread around minus the excessive wiring.QuoteI have it around 2-3% for lightning. Everything else is cooking/heating/TV/PC.In commercial buildings that percentage is high merely because all they have is lights and PC's.QuoteNot all and not 100%.QuoteYou are forgetting that energy efficient is not everything. Things have to be cost-efficient as well.Ordinary fluorescents can be dimmed, pulsed dimming, same as with LED's.Just not with ordinary dimmer - triac with some EMI filtering.But output goes 20% down with only 5% lower voltage so dimming has to be precise. And with low power outputs there is something similar to strobe effect when you 'see' plasma moving around the tube.However. It works and it works very well. Just look at the number of LCD panels made with cold-cathode tubes inside. Everyone of them that has adjustable brightness proves the concept works well.However, forget about CFL's and dimming. These things are worthless even without it. Low power output on start, fast aging, dying electronics due to excessive temperatures in the fixture. 8000h rated at 50% failure rate and so on and so forth.LEDs also loose their output over time (forget about 40k hours with power leds, perhaps 10k or not even that) and _have_ to be cooled with really big heatsinks if you want them to be passive - that adds to the cost as well.Also pulsed dimming with led's is useful for preserving the same light temperature but does not spare the led. It is much better to step down on voltage a bit (analog dimming) and then use pulsed dimming, you gain some efficiency at lower led output and don't stress it as much.Also. Light drops out at higher temperatures.Converting whole electrical system to 12/24V DC would be a good idea, also, you could use power cables for data communication as well, few wires less.