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Topic: Remote Control Socket - Some Guidance? (Read 695 times) previous topic - next topic

Xerosigma

Dec 02, 2012, 08:02 pm Last Edit: Dec 02, 2012, 09:47 pm by Xerosigma Reason: 1
This is my first micro controller project and would really prefer to have some guidance before proceeding with my venture.
I'm attempting to create a remote controlled outlet, here are the design specs.

Socket Control Board with Wi-Fi capabilities | Budget Per Device: $60 (Aprox.)


Now my general goal here is to have an Arduino Duemilanove (for price) be the control board.

Q #1: I do not know if it's possible to install a wifi tranceiver on it though. Any suggestions on how I should go about this?

Now the idea is to have several Arduinos connected to a network administrated by a single Raspberry Pi Server. I'm all software and can handle the server and network setup. But this poses my next question:

Q #2: How would one go about pushing Arduino device data to an accessible program interface? The goal is to have each Arduino push it's current state values to the server, where I can then control them on the server.

Last but definitely not least:

Q #3: Are there any additional parts/modules I should consider to avoid potential issues/malfunctions that I have not listed above? Additionally, are these the correct parts for such a task?

Thank you so much for your time in advance!

Concept Image:

retrolefty

Well the nice Arduino folks do make and sell a WiFi shield that attaches directly to an Arduino board.

http://arduino.cc/en/Main/ArduinoWiFiShield

I can't help you with any of your other questions.

Lefty

Xerosigma

Trying to avoid the shield to reduce costs but thank you for reply. Greatly appreciate it.

PeterH

You're going to be switching main electricity? That is quite easy to do, and quite hard to do safely - are you sure you understand the risks and know how to address them?

Will this device be mains powered?

If you're using TCP/IP over WiFi networking then you have almost unlimited options available to you - I'd be inclined to go for a web service based architecture with a central database and command+control server.

Do you have a budget per device?
I only provide help via the forum - please do not contact me for private consultancy.

Xerosigma


You're going to be switching main electricity? That is quite easy to do, and quite hard to do safely - are you sure you understand the risks and know how to address them?

Will this device be mains powered?

If you're using TCP/IP over WiFi networking then you have almost unlimited options available to you - I'd be inclined to go for a web service based architecture with a central database and command+control server.

Do you have a budget per device?


1: I most definitely do not understand the risks and how to address them. Would you be willing to share some knowledge?

2: The device will be mains powered.

3: That is the goal. I'll most likely go with a simple LAMP stack on the Raspberry Pi.

4: Budget for device is approximately $60.

Thank you so much for time!

Henry_Best

Xerosigma,

You can't power an Arduino directly off of the mains. You will have to use a wall wart or some other form of transformer/rectifier to power it.

You only need to switch the live [hot] wire that's going into the sockets. SWITCH OFF THE POWER TO THE SOCKETS AT THE FUSEBOARD! If you can, remove the fuse and put it in your pocket (to stop anyone else replacing it whilst you're working). Disconnect the live [hot] wire from the back of the sockets and connect it to the middle screw terminal on both of the relays. Be sure  any connections are well insulated. Next connect one of the other (normally open or normally closed) screw terminals on each relay to the live inputs at the back of the socket. Again, carefully check the insulation of every connection.

You may now restore power to the sockets. If you find that the sockets are not on (or off, whichever you want), you need to use the other output screw terminal of each of the relays. Don't forget to switch off the power first before changing them.

Make sure that all your mains wiring and the relay board are insulated. I suggest a plastic project box for the relay board with a hole to allow the mains cable out at one end and another hole, as far away as possible, to allow the low voltage control wires out. Keep the holes as small as possible to prevent 'fingerpokin'.

wizdum

If you want cheap wifi, you should look into the RN-XV modules:
https://www.sparkfun.com/products/10822

And an xbee Explorer to do the voltage conversion for you:
https://www.sparkfun.com/products/9132

You will need to put a pullup resistor on the DIN pin on the RN-XV module itself to make it work with the xbee Explorer.

These modules are not good for servers, since they can only handle 1 connection at a time, but they make great remote trancievers.
"Anyone who isn't confused really doesn't understand the situation."

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Lakes


PeterH

Yes, the mains voltage relay and a couple of wires solution shows how easy it is to make it work, but addresses none of the safety issues.


1: I most definitely do not understand the risks and how to address them. Would you be willing to share some knowledge?


Mains voltage is dangerous. If your product goes wrong, you could quite feasibly kill yourself or somebody else - either through electric shock or a fire. It is likely to go wrong in ways that you did not anticipate.

Your problem is to ensure that there is no failure mode that could connect mains voltages to any of the low voltage components, and that high and low voltages are physically as well as electrically isolated. In practical terms, the only sensible way for a novice to do this safely is to use a commercial component for the mains switching. A mains voltage relay is a good starting point and gives you electrical isolation, but you still have to deal with physical isolation of the circuits to and from the relay. If you use a PCB, you need to ensure that the high and low voltage parts are physically remote and sufficiently insulated from each other and that the high voltage part is fully insulated. If you use discrete wiring you need to ensure that the wiring is properly terminated into sockets and everything is mechanically secured.

While this is all doable, there is a very real danger that a novice tackling this problem will overlook something. By far your safest option would be to use a commercial product for the whole mains voltage part rather than try to design and build your own switch.
I only provide help via the forum - please do not contact me for private consultancy.

zoomkat

You might wan to look at some of the x10 and home automation vendors to see what they have in the way of automated outlets. Might save on running a lot of wires. Also, search the forum for x10 information.
Consider the daffodil. And while you're doing that, I'll be over here, looking through your stuff.   8)

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