Need help on room ventilation control project

Discussion in 'The Projects Forum' started by warcuz, Nov 4, 2009.

  1. warcuz

    Thread Starter New Member

    Jul 10, 2008
    7
    0
    I need some help with a project I'm making, Ok the idea is I need to make a device which can switch on and switch off the ceiling fan of a number of rooms at a given time. I need to use a PIC micro controller;

    Theres a computer wherein we could monitor the fan of separate rooms, ok lets say for example there are 3 rooms , exactly 8am the fans of room 1 and room 2 switches on while that on room 3 must be off. Now at 9am 1 hour after, the fans of room 3 would switch on, room 1's fan must continue to be on while room 2's fan would be off.

    The fans must be controlled wirelessly. The fans can be manually switch off
    but cannot be manually switch on.

    Now my idea for this project is that I need to use transceivers.
    So it goes like this:

    Input device (personal computer) => transceiver => transceiver =>PIC micro controller =>output device(switch/fan)

    Did I place the PIC micro controller in the right position?
    The one that I've shown above is only for 1 room, If there are 3 rooms
    would the idea be the same?

    Transceivers are expensive and added micro controllers would sure cost a lot I think. Is there any way to lessen the cost of this project? I have a friend and he said that we could only use 1 transceiver for 3 rooms, he mention about using cables instead connecting the three rooms to minimize the cost is that possible?

    I need help for an idea for this project, to improve it and lessen the cost
    Can you recommend resources,sites , books etc. The theories behind my project would aid me to fully understand the circuit. And I don't have any circuit until now for the said project:D
    if you happen to know a circuit which is similar or very related to this project I appreciate it if you send it to me.

    A lot of thanks in advance
     
  2. Duane P Wetick

    Active Member

    Apr 23, 2009
    408
    19
    You can save yourself a lot of money by using one of the small PLC's (programmable logic controllers) now available on the commercial market. It means wiring each of the 3 fans to an output triac on the PLC. The big advantage is now each channel (fan) can be programmed to come on or shut off at any time as you see fit. These controllers have come down in cost over the years and are programmable by laptop USB port.

    Have fun! Duane
     
  3. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    Depending on how big your house is, you could get away with just one micro for all rooms, this one micro can control each fan via a single Receiver on each fan module.....

    Since the fans are controlled with simple on/off functions (unless you want to get info from the fan module to see if it is actually on or off...)

    You could use some Holtek encoder / decoders (latching output type like the HT648L decoder )for the micro and fan controls, each fan controller can be set with a unique address bit and that way the micro can set its own encoder address programatically depending on which fan module it wants to control... the outputs of the decoder IC's can be used to drive an SSR (Solid State Relay that can handle the fans current draw, try searching Digi-Key for Crydom Solid State relays....) you could mount all the receiver electronics right inside the fan housing....

    You could connect the Micro to the computer a few ways, wireless, ethernet, or RS232....... ethernet would be cool, then you can have access to the fan controls on any computer, possibly even over the internet if you included an HTTP server on the micro which could serve the html pages from an SD Card (I have done a similar setup with my B.U.M. System [Bathroom Utility Managent System] I can actually turn on/off anything in my kids bathroom (shower/lights/sink faucet/ exhaust fan, water temp, etc.) from anywhere in the world as long as you have the system connected to the Internet.

    My .02
     
  4. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234

    PLC's are moderately priced depending on the I/O's required, but the software to program them usually costs an arm and a leg (then you have to program in Ladder Logic)..... I used to use PLC's a lot, now I just make my own basically with Pic Micro's....... cheaper!

    My .02
     
  5. warcuz

    Thread Starter New Member

    Jul 10, 2008
    7
    0
    So I need to use 'PLC' not 'PIC' ? but what if I want to know if the fan is 'ON' or not could a PLC handle such? Do I really need to use transceiver, I want it to be wirelessly connected from the 'computer'. And in this project, would I only be needing one micro controller. Do you know any circuit that is at least related to this? its good to have a reference...I dont want to blow things up : ).
    Thanks a lot in advance
     
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