434Mhz RF Remote Control Receiver picking up stray signals

Discussion in 'The Projects Forum' started by devilfrmheaven, Oct 28, 2009.

  1. devilfrmheaven

    Thread Starter Member

    Oct 28, 2009
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    Hi,

    I have managed to build an RF Remote control for my bike I have referred the circuit below to make it. It is working fine, but my problem is that the receiver is picking up stray signals especially from our local TV stations. The circuit just turns on all the lights like crazy. Is there any way to avoid these stray signals? :confused::confused::confused:


    [​IMG]

    [​IMG]

    Regards,
    Devil
     
    Last edited: Oct 31, 2009
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    You need to set matching address codes in both the encoder and decoder (tie individual pins high or low to make a pattern known only to you). I checked the Reynolds site and didn't see that described clearly. It may be there, and I just missed it.

    Here is another project that does that. Sorry it is so lengthy. You might be able to find shorter descriptions by searching on "setting holtek code," or similar.

    Link: http://www.dogpile.com/clickserver/...23=0&40=caIGwCR6waJu7VRzEabazA==&_IceUrl=true

    John

    Edit: I found this datasheet to give a better description than the Holtek datasheets. Note: The MC145026/145027 can read either two states, like Holtek, or three states.
     
    Last edited: Oct 28, 2009
  3. devilfrmheaven

    Thread Starter Member

    Oct 28, 2009
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    Thank you for the reply jpanhalt, I have setup the encoder and decoder just as you told
    But the thing is that the transmitter picks up stray signals I guess and then switches on the lights and all other connected systems.

    I dismount the system from my bike and connect it to a circuit in my garage and every thing works perfect.....

    Any way let me try using the IC's that you have mentioned MC145026/145027 :)
     
  4. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    It sounds like your problem is in the connections on the bike, not the RF link. I am assuming you mean receiver, not transmitter, is picking up stray signals. Can you post the actual circuit you are using on the bike?

    I used the exact TX/RX system you apparently have from Reynolds about 10 years ago and never could get it to be completely free from an occasional false signal, but they were quite infrequent. I switched to Linx RX/TX and had no problems. Another option is just using a key fob and matching receiver.

    The key fobs and Linx units are described in standard parts catalogs, like digikey.com.

    John
     
  5. devilfrmheaven

    Thread Starter Member

    Oct 28, 2009
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    mods can you please change the title of the tread from 434Mhz RF Transmitter picking up stray signals to 434 Mhz RF Remote Control Receiver picking up stray signals

    jpanhalt you got it right im sorry the reciever is picking up stray signals and activating my relays which makes my lights and other circuits work like crazy... have requested Mods to rename the title :)
     
  6. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    It is still not clear to me where or when the problem is occurring. If you turn the receiver on, have an address code set in it, have the bike off, and have the transmitter off, do the outputs on the receiver produce random signals? What happens if you change the address code?

    Maybe your loads are interfering with the power supply to the receiver. If you remove the heavy loads, does the interference seem to change?

    The fact that it works perfectly on your workbench, but not when installed on the bike is pretty strong evidence that the problem is in the installation on the bike. Can you provide more detail about that installation?

    John
     
  7. devilfrmheaven

    Thread Starter Member

    Oct 28, 2009
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    John,

    I tested the circuit without my receiver, the lights never lit up.

    The problem actually is that the receiver is picking up signals from the cables laid for TV and Internet.

    I am looking for a way to clear up the unwanted signals...

    Devil
     
  8. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Why did you test it without the receiver?

    But, you also said:
    Why would there be interference when it is mounted on the bike, presumably while it is in your garage, but not when it is not mounted on your bike? Spurious radiation from TV and Internet cables is extremely low. So, I think those sources are extremely unlikely (and of the wrong frequencies too).

    From what information you have provided, the "unwanted signals" are most likely coming from the electrical system in your bike. What is the wiring diagram for how you attached this receiver to your bike? Have you tried any filters in the plus (+) supply to the receiver? Have you tried disconnecting any of the loads? Does it occur when the bike is not running?

    John
     
  9. devilfrmheaven

    Thread Starter Member

    Oct 28, 2009
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    Thanks to my PC ... my circuits are all gone cauz of a crash.. im redrawing the circuit...I will post the circuit shortly... I disconnected the receiver just to know if the receiver is picking up the signals or the variations in power supply to the IC HT12D is the problem...

    I noted down the locations when the lights went crazy and one of my greatest break through was when I parked my bike in a store. I was not able to switch off the lights at all.. The Remote will turn of the light when it is pressed.. and the lights will automatically turn on when I release the switch. I was able to switch off the lights only I moved the bike atleast 10 meters away from the store... and also the light goes on when there is a cable crossing across the road...
     
  10. devilfrmheaven

    Thread Starter Member

    Oct 28, 2009
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    John,

    I have not connected A0 to A7 in the receiver circuit and the Transmitter...

    Can Earthing the A2 and A5 pins for both transmitter and the receiver solve the problem??
     
  11. hgmjr

    Moderator

    Jan 28, 2005
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    Thread title changed per your request.

    hgmjr
     
  12. devilfrmheaven

    Thread Starter Member

    Oct 28, 2009
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    hgmjr Thanks man!!!
     
  13. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    By all means, you should set a code. Without the address code, you will pick up everything on 434MHz. The code is binary (on or off for each bit). All zeros (earthed) will work, but you are probably better picking something else. Set the same code in the TX and RX, be sure it works in an electrically quiet place, then try it outside. From an earlier post (#3), I was under the impression that you had set a code.

    I just looked at the HT12D datasheet briefly. It says the address bits can be set either to ground (Vss) or to your positive (Vdd). It doesn't say whether open is interpreted as a 1 or as a neither (like the other chip I mentioned). Maybe that information is buried in it somewhere; I didn't read it that carefully. In any event, pick a binary number, such as 10110000 (for A0 to A7). For testing, connect the 1's to Vdd. You can use a 10K resistor for that, if you want. Connect the 0's to Vss (earth/ground). Do the same on the receiver and transmitter.

    See if that helps and please let us know what happens.

    John
     
  14. devilfrmheaven

    Thread Starter Member

    Oct 28, 2009
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    John, It worked.... I grounded A7, A6, A5, and A4 in both reciever and the transmitter,.. and this solved the issue....... :)...


    Thank you for the help!!!!!!
     
  15. devilfrmheaven

    Thread Starter Member

    Oct 28, 2009
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    Hi John,

    Is there an alternate circuit other than the HD12E??

    Now its like when I press the 1st switch its like 2,3 and 4 is high and 1 remains low similarly if I press 2 then 1,3 and 4 is high and 2 is low.

    Is there any way to make it one press switches on something and another press of the same switch switches off the same??


    [​IMG]
     
  16. hgmjr

    Moderator

    Jan 28, 2005
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    You realize that you need to use an encoder HT-12E (at the transmitter) and a decoder HT-12D (at the receiver), right?

    hgmjr
     
  17. BMorse

    Senior Member

    Sep 26, 2009
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    You need to get a matching Encoder Decoder with latching outputs, the ones you are using are momentary..... Try the HT648L series of decoders with latching outputs....
     
  18. devilfrmheaven

    Thread Starter Member

    Oct 28, 2009
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    BMorse thanks a lot for the reply!!!

    I think I can use this IC more effectively.


    Regards,
    Devil :)
     
  19. devilfrmheaven

    Thread Starter Member

    Oct 28, 2009
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    Got it right this time.. everything is working perfectly now... :)

    was just trying to make another remote for my room lighting and other appliances :)
     
  20. devilfrmheaven

    Thread Starter Member

    Oct 28, 2009
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    Bmorse,

    Dont really know if im asking a foolish question, but what is the difference between HT12D and HT648L both says that its latch type.

    devil.
     
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