Why using (cat5) cable?
Wireless is very nice, but out of reach within the target costs per node. It would require a transceiver and a 230V power supply per node. Cat5 cable is the cheapest cable on the market today (even cheaper than simple twisted wire). Powerline communication is possible to but also rather expensive and requires operations in the meter cupboard when you have more power groups. Not really a do-it-yourself operation. Furthermore, on some places where you want to switch or detect something there is no 230V nearby. For example at curtains, window break detection or at door open/close detection. So in this case you need a cable anyway.
Do i need a PC?
You need a PC to talk to your nodes. The system does not need a PC for regular operation. All nodes are intelligent and perfectly able to communicate among each other. Also, there is no 'central intelligence'. For the minikit you only need a PC if you want to reprogram the chips. In that case you need a standard AVR programmer too.
Are there any smd components?
No, for most of us, smd is beyond do-it-yourself.
Do i need special skills?
The schematics are not particularly complex, but you may need to work with 230V~. In order to do so in a safe manner, you need education in that area. In some countries it may even be illegal to work with the mains without the proper education and certification. You take full responsibility when you build and connect the circuits you build.
Why a homebrew communication protocol?
The most important reason is costs. Ethernet, CAN, RS485 etc would cost more to implement than my solution. I do not say my protocol is better, probably it is not. But it is cheaper to implement over all. Second reason is complexity. Ethernet and CAN for example are not easy protocols (yes I have worked with these on detailed level). I wanted it to be understandable for everyone. Another reason is that I wanted that to network would be topology free, and (virtually) unlimited of size. This rules out a lot of bus systems too.
Is it allowed to connect the circuits to the mains?
Local legislation may require extra filter and fuses or circuit breakers, before you may connect circuitry permanently to the mains. Do not ignore these!! They are there for your own safety and the safety of others. If a fire breaks out and you did not follow local law, you may get into problems. It may even be that the design on this site violates your local regulation. Verify! If you find error, please let me know. Thus, know what you are doing, and make sure you are qualified to handle mains. For the Netherlands, I think you can start with NEN1010 in Europe you have at least to take care of HD384 and in international context, please take notice of IEC60364 This is by no means a complete overview. Make sure you get acquainted with your local situation.
How do I automate my whole home?
This project is work in progress. I will publish the different parts as they become ready. You are free, and invited to, post your own ideas. At this moment is it possible to switch and dim normal lights, halogen lights and switch led and power saving lights through relays.
Can I modify the programming?
All nodes come with an ISP connector and the AVR microcontrollers can be programmed with any programming device. Since all IC's are mounted on sockets, they are removable and can be programmed in separate programmers too, such as the STK500.
Can companies also participate?
Sure, there is no real difference. If you want to install this stuff into your building, go ahead! However, if you have commercial plans with any part of this project, contact me first. The current license does not allow for commercial use. A second point of attention is that companies pay a handling fee (100 euro) when ordering.
It this for Europe only?
For the moment it is targeted at Europe, since we all have the same mains (230V~, 50Hz). In other countries, the modules may (probably will) work. But I have nothing tested in that area.
Will you publish your pcb designs?
Yes, but not right away. The point is, they have to be in sync with the circuit diagrams. Keeping that up is already a lot of work. I think it is more important to keep the circuit diagrams and documentation up to date for now.
Why are the evaluation kits so expensive?
The design is targeted on 15 euro/node on average. The kits that contain an access point are relatively expensive because those costs are divided over just a few nodes. But it is intended for a whole net with dozens of nodes! Unfortunately this is the most expensive part of the system. But the more nodes you have the less it costs per node. Furthermore, the target price is only achievable when the nodes are built in large quantities. The mini evaluation kit does not fulfill that requirement if you build it by yourself. The more people that join, the cheaper it gets! And, last but not least, over 25% of the price is taxes and shipment. (That you have to pay anyway.)
I am a company and do need to pay taxes!
True, state in your order that it is a company order and include your VAT identification number. Remember that companies pay a handling fee of 100 euro.
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