Need asaistance to close a circuit

Discussion in 'The Projects Forum' started by Henniebrandweer, Nov 7, 2018.

  1. crutschow

    Expert

    Mar 14, 2008
    20,075
    5,654
    That should work also.
    Could save an embarrassing dump of your bike in the garage.

    Note that to minimize transients from the relay coil damaging anything, you should add a 1n4148 diode across each coil (diode anode to ground).
     
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  2. Henniebrandweer

    Thread Starter New Member

    Nov 7, 2018
    21
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    Ok so I drew this up quickly. That would work right?

    Ok and on this website, which of these relays would you choose? Smallest that will work.. im iot so clued up with these things and this is the only shop close to me

    http://www.electronics123.co.za/#search=Relay
     
  3. Henniebrandweer

    Thread Starter New Member

    Nov 7, 2018
    21
    1
    Wow! Well thanks for the input but I really dont agree with your post... I am trying to implement all safety features as far as possible.... You're statement doesnt have much ground as I already have done the mod so that 2 out of 3 safety precautions still operate and using the 2nd relay it will ensure the nutral safety also works. So please Im on a mission here to get the full function of my alarm system working, and its something I want. I am here to ask advice and rhereare already a couple of nice people assisting me here... I dont want to be rude but to tell someone "stop, dont do it yourself" where I have never backed down from a challenge before is kinda not cool.. I mean I am really trying to do it all as safe as possible as far as I go.. its not a fly by night type of job this. Its for my BABY.. I would do all I can to prevent a tip over or worse as atm I dont even have insurance on it.... So why would I risk being stupid.

    At yhe end of the day, its a cool feature that allows you to remotely start your bike for a bit of warmup... Which is something many peaopllike so btw. I am doing it coz I want to....

    Please look and see that as I go Im really trying to figure out a way to have it all without compromising any safet features.

    Oh and in anyways, not all bikes has these safety features, in fact, most have none of them.. so I can promise you that the insurances jn SA dont have a list of things like "clutch switch" , "Neutral safety switch" or "side stand safety switch" which they tick on inspections.

    Only my opinion. But I understand your concern and appreciate all feedback
     
  4. Henniebrandweer

    Thread Starter New Member

    Nov 7, 2018
    21
    1
    Could you perhaps explain this more in detail? I have not done anything like this before
     
  5. BR-549

    AAC Fanatic!

    Sep 22, 2013
    4,074
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    "Could you perhaps explain this more in detail? I have not done anything like this before"

    This is a safety device. It is against the law to defeat or modify an interlock.

    If you won't consider the safety of you and yours'.....please consider this site's rules and liability.

    This is not personal towards you. Let someone that understands do this job for you. You are not competent. Can you rate the components needed?

    That is not personal also.
     
  6. crutschow

    Expert

    Mar 14, 2008
    20,075
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    The relay coil has inductance which can generate a large voltage spike when the switch driving the coil is opened.
    A diode across the coil will absorb that spike to it doesn't damage the switch or any other circuitry connected to that line.
     
  7. Henniebrandweer

    Thread Starter New Member

    Nov 7, 2018
    21
    1
    Thank you for your patience... I will read up on this before building the circuit.

    I really appreciate your help
     
  8. crutschow

    Expert

    Mar 14, 2008
    20,075
    5,654
    Here's a Wikipedia article on diode suppression of an inductor spike.
     
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  9. Henniebrandweer

    Thread Starter New Member

    Nov 7, 2018
    21
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    Hey there...

    Ok so I bought the relay and diods today... managed to build the circuit and test it out.. then I ran into another issue.. I only presumed that the Neutral Switch would give out 12v.. but it doesnt, it gives out like 10.5v and I tested, its not enough to activate the relay coil.... So tomorrow I will have to see if I can find another place on the harnes where I can get closer to 12v when in Neutral...

    Will post when Im done. Thanks again for the assistance
     
  10. Henniebrandweer

    Thread Starter New Member

    Nov 7, 2018
    21
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    I also put a diode on the positive input side of the relay coil between the relay and positive input, to protect the diode between the posts in case of accidental reverse polirization.
     
  11. MaxHeadRoom

    Expert

    Jul 18, 2013
    16,226
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    That loses you around .4v to .7 v!
    A 12v relay hysteresis usually allows a 12v relay to operate at 10.5 pick-up.
    Max.
     
  12. Henniebrandweer

    Thread Starter New Member

    Nov 7, 2018
    21
    1
    Damm.... Ok, I will test it all before completing... If the extra diod will cause such a loss, especially if the relay wont open or close.. then I will just have to leave the extra one out...
     
  13. crutschow

    Expert

    Mar 14, 2008
    20,075
    5,654
    You may have to add a transistor to operate the relay from the Neutral signal.
    Below is a typical circuit:
    It requires just one resistor and one transistor, besides the diode that would be used anyway.
    upload_2018-11-8_11-11-15.png
     
    Last edited: Nov 8, 2018
  14. Henniebrandweer

    Thread Starter New Member

    Nov 7, 2018
    21
    1
    Cool, Guess im going back to the electronic shop tomorrow...lol
    Thanks
     
  15. Henniebrandweer

    Thread Starter New Member

    Nov 7, 2018
    21
    1
    Tell me, with the resistor and transistor values indicated here by you, what would the range of voltage be required to operate the transistor effectively?
     
  16. crutschow

    Expert

    Mar 14, 2008
    20,075
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    Okay.
    The transistor can be just about any small, general-purpose NPN, if the 2N2222 or variant (such as the PN2222) is not available.
     
  17. crutschow

    Expert

    Mar 14, 2008
    20,075
    5,654
    The transistor will operate down to a couple volts at the input, but the resistor value would need to be proportionally reduced.
     
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  18. Henniebrandweer

    Thread Starter New Member

    Nov 7, 2018
    21
    1


    Thanks all. Im done with my project
     
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