Controlling A Lamp With A Wireless Phone

Discussion in 'The Projects Forum' started by Joseph Watson, May 28, 2015.

  1. Joseph Watson

    Thread Starter New Member

    May 27, 2015
    7
    11
    I discovered a cool way for remotely controlling something using an extra wireless phone. We had used a wireless phone for some years. It had two handsets, one at the base unit and another one that sat in a charger in another room.

    Later, we wanted to add a third handset in yet another room. The easiest way to do it was to buy a three-handset system so we replaced the whole setup, locating the third handset and its respective charger in the new room.

    I boxed up the old two-handset phone system and set it aside.

    One day, we decided we wanted to have a lamp that we could control from a remote location. There was power available where the lamp was to be located but there were no easy ways to provide a control signal. I considered an X-10 control system which delivers control signals through the power wiring but I am cheap and so I look for ways to do things without spending money.

    I pondered the idea of how difficult it would be to use the spare wireless phone system to do the job and it turned out to be surprisingly easy. Basically, I just needed to add an AC adapter to provide a source of DC power, a solid state relay, a modular phone plug to fit the phone base, and the wiring for the lamp.

    The schematic shows how I connected everything.

    Remote Lamp.jpg

    The solid state relay required an input signal of 3 volts to 8 volts. I chose an AC adapter with a 7 volt DC output which turned out to be just enough for the job. A few volts more would not have hurt.

    When you plug a modular phone cord into the Line jack on the back of the phone base, the two middle wires (usually color coded red and green) are the two that connect to the phone line. When the phone is not in use, these two wires present a high impedance to the phone line. That is, in DC terms there is a very high resistance between them. When you press the Talk button on the phone handset, these two wires present a much lower impedance to the phone line which, in DC terms, is a fairly low resistance. We can use this characteristic to control an external circuit even when it is not a telephone line. Generally speaking, these two wires (red and green) are not polarity sensitive and can be used interchangeably.

    In the schematic, you can see that the DC output from the AC adapter will be applied to the DC control input of the solid state relay if the phone base conducts. That will turn on the solid state relay and the lamp will be lit.

    Once everything is interconnected, plug in the phone base's own AC adapter, the plug for the lamp circuit, and the AC adapter that powers the solid state relay. Also plug in the separate charging station for the phone handset. After the handset has had a chance to charge well, you may have to place the handset into its position in the phone base so that it can sync up with the phone base. This only takes a few seconds. Then remove the handset, press the Talk button and the lamp should illuminate. Pressing the End button on the handset or just placing the handset into its own charging station will cause the lamp to be extinguished.
     
  2. ScottWang

    Moderator

    Aug 23, 2012
    4,855
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    The project you posted, it must be a completed project and it can be reduplicated by the members, but now you only shown the block diagram, please complementing the details, when you finished then the posted will move to the completed project, thank you.
     
    Joseph Watson likes this.
  3. Joseph Watson

    Thread Starter New Member

    May 27, 2015
    7
    11
    This is the first project that I have posted. I am sorry, I thought a completed project was one that was working properly and the hobbyist/experimenter was not looking for advice on making it work.

    In this case, the finished schematic is little different from a block diagram since nearly every component is basically a block. My schematic was sufficient for me to wire this project and to explain to friends what it was. Still, I understand that others may need more detail. Here is as much as I can provide:
    • Mount the parts on a suitable insulating surface. Most plastic material or dry wood will work.
    • Every component that I used in this project came from my "junk box".
    • One of the key components is the solid state relay. A solid-state relay (SSR) is an electronic switching device that switches on or off when a small external voltage is applied across its input terminals. The unit I used was manufactured by Crydom and marked as I have shown. Many types will work in this project. Be sure the input side is marked to accept 3 Volts to at least the DC output voltage of the AC adapter (7VDC in my case). Be sure the output side is marked to control at least enough current to handle the load. For a 60 Watt lamp, any unit rated for at least 1 amp will be more than sufficient. Also, be sure the output side is marked to control AC (not DC) and of a voltage at least as high as the mains supply voltage (that is, 120VAC or more).
    • Most any AC adapter that produces 7VDC can be used since the current demands on it are quire low, on the order of perhaps 10 to 30 ma.
    • Keep the high voltage (120VAC) wiring away from the other wiring for the sake of safety. Otherwise, wiring layout is not critical and is mostly a matter of convenience. If you are not experienced with working on high voltage circuits, consult an electrician for help.
    • Mount the lamp socket such that heat generated by the lamp will not undesirably affect any nearby materials. Use proper eye protection when using hand tools during construction.
    • Do not connect power to the circuit until wiring is complete and you have double-checked the wiring.
    • During testing and use, remember to use proper precautions when working around high voltage circuits.
    • It is a good idea to enclose the finished circuit in a well-insulated enclosure, leaving the phone base, the AC adapters, the lamp, and the lamp's AC plug outside the enclosure. Be sure to use proper strain reliefs on all wires passing in/out of the enclosure.
    • Locate the project out of the reach of small children, away from moisture, and away from sources of extreme heat.
    • Keep the wireless phone base outside of any metal enclosure as that would impair its ability to communicate with the handset.
    Here is a more detailed schematic.

    Remote Lamp details.jpg
     
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  4. ScottWang

    Moderator

    Aug 23, 2012
    4,855
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    The file you attached that is not a schematic, it just a block diagram, you can also see it from my second project.

    In The Completed Projects Collection Forum that it need the completed schematic and PCB photos, if that is the uC stuff that it should be included the source code or at least has the *.hex code or the code members could program and duplicate, you could see the results from members, no matter big project or small project, we are welcome you to sharing for the members.

    These are my old projects.
    Two 4 kinds ±5~15V fixed power.
    Two Sets 10 channels O'scope and Multimeter Multi-Inputs Selector.
     
    Joseph Watson likes this.
  5. alfacliff

    Well-Known Member

    Dec 13, 2013
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    a block diagram like this might be better than a schematic in this case, since not everyone would have access to the type of phone and other stuff that was used. like the spectrum analyser i put together, not everyone has the same tv tuner and cable tuner I had, so a "heres how I did it" would be apropriate.
     
    Joseph Watson likes this.
  6. ScottWang

    Moderator

    Aug 23, 2012
    4,855
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    Thanks for your opinion, I will discuss with other mods, if they say ok then this will move to The Completed Projects Collection.
     
    Joseph Watson likes this.
  7. ScottWang

    Moderator

    Aug 23, 2012
    4,855
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    Could you attach some photos about the wireless controller as other members did, if you complement the photos then this thread will be move to The Completed Projects Collection forum, we just want to avoid that the other members following that there is no photos to post in the completed projects, thank you.
     
    Joseph Watson likes this.
  8. Joseph Watson

    Thread Starter New Member

    May 27, 2015
    7
    11
    I think attaching a photo of my version of this project would be counterproductive. I threw it together one evening in great haste. It is a real hack job. For example in my version of this, the solid state relay is still attached to a PC board that was salvaged out of an old piece of equipment. I just cut away appropriate traces and soldered to the board as needed. For a plastic enclosure, I re-purposed a plastic container once used to bring extra food home from a restaurant ("a doggie box"). I chopped a little hole in the end of it to allow the wires to pass out of the enclosure.

    When I put this together, it was just a crude experiment but it surely worked out well for me. I was not thinking in terms of building something in which to take pride (other than it does work well).

    After nearly 60 years of electronics design and hacking, I pretty well know what I can get away with but I would never recommend that others build this project to look like mine. Perhaps a better approach is that we ask that anyone else who does repeat this project photograph their work and post their photos.

    The real spark of creativity in this project is that one can think of a surplus wireless phone as a sort of remotely controllable switch of sorts. Unlike an ideal switch, it has some effective internal resistance but it can be made to do something useful.
     
  9. ScottWang

    Moderator

    Aug 23, 2012
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    I think the people here, when they check the stuffs of completed projects will like to see what the results looks like, we can't force you must be take the photos very details, let's see what you can do and also waiting to watching what the members could except.
     
    Joseph Watson likes this.
  10. joeyd999

    AAC Fanatic!

    Jun 6, 2011
    2,691
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    @ScottWang:

    I think he did a fine job. If it were my place to do so, I'd say, "back off."

    But it's not, so I won't.
     
    Joseph Watson, ebeowulf17 and Johann like this.
  11. ScottWang

    Moderator

    Aug 23, 2012
    4,855
    767
    Thanks for your opinion.
    I'm not going to do the job only according what I want, it should be cosidering the forum and the members and the fair issue, now we accept no detail schematics, if even there is no photo, if some other members following that condition, what will the completed projects forum look like?

    If more and more members accept this thread no need the photos and can be move to the completed projects forum, then we can discuss some more.

    I would like to know if there are more and more members asked for the same condition is that no photos, what will you do?
     
    Last edited: Jun 1, 2015
    Joseph Watson likes this.
  12. Johann

    Senior Member

    Nov 27, 2006
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    30
    I think he shared his experience with the forum. It worked for him and the schematic is quite clear as to what he achieved. The base set just acts as a switch completing the LV circuit of the SSR. The SSR turns on whatever you like. Simple enough.
    Thanks for sharing, Joseph!
     
    Joseph Watson likes this.
  13. ebeowulf17

    Active Member

    Aug 12, 2014
    678
    79
    I certainly understand the desire to maintain boundaries and that making exceptions to rules can be a slippery slope.

    Having said that, I think that the second diagram provided is well drawn, very clear, and conveys all that is needed for this particular project.

    Also, congrats to the op on having a clever idea and on successfully executing it. It's a pretty cool trick!
     
    Joseph Watson likes this.
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