relay advice please

Discussion in 'General Electronics Chat' started by mpooley, May 11, 2010.

  1. mpooley

    Thread Starter Active Member

    Mar 3, 2010
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    I am thinking of buying a USB experimental interface board.
    http://www.quasarelectronics.com/velleman/k8055-usb-experiment-interface-board-kit.htm

    The outputs are 50v 100ma max - could i drive relays from this? they would be switching 230v ac 5amps

    I have searched for relays but havn't found any yet.

    I have one other question if you don't mind.
    I wish to wire in the inputs to a "1 wire" temperature sensor network do you think this would work, I would use the pc to read the network (if i can find the software lol)
    it's a very long time since i did any electronics and nothing like this stuff, so am a bit unsure of myself.

    any advice would be appreciated

    Mike:confused:
     
  2. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    1,015
    69
    You should be able to drive 12V or 24V relays, whichever is most convenient (I don't know what power supplies you have available).

    The 1 Wire interface needs fast timing, I doubt you can use a general remote I/O unit, unless it has a serial port?

    You can send dummy characters to pulse the data in to the device, and by looking at which bits are low or high in the echoed data, you can tell if the 1 wire device sent a zero or 1.
    The interface needs the RS232 levels converting to open-collector 5V level and back to RS232 voltages, with loopback implemented at the 5V stage. That is also where you connect the 1 wire device.
     
  3. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    What is the make and model of the 1-wire temperature sensor?

    And are you trying to connect this sensor through the relay as well?
     
  4. mpooley

    Thread Starter Active Member

    Mar 3, 2010
    35
    0
    thanks
    The power is derived from the usb interface I believe.

    Mike
     
  5. mpooley

    Thread Starter Active Member

    Mar 3, 2010
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    0
    The DS18s20 and no, not throught the relay.
    I want to add at least two- 1 wire ccts with several DS18s20 sensors on each. to the digital inputs.

    thanks

    Mike
     
  6. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,535
    If you are using the USB power you might want to check out SSRs (Solid State Relays). They are optocoupled triacs, but are really easy to use. Basically you provide enough current and voltage to light an internal LED (typically 3-7V at 3ma) and they can switch 120VAC-220VAC up to 10 A with heatsinking. Their weakness is they don't handle inductive loads such as motors very well.
     
  7. mpooley

    Thread Starter Active Member

    Mar 3, 2010
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    thanks they sound interesting, but I want to drive 3 zone control motors for my heating, I assume they are stepper motors I'm not sure.

    But wether that makes a difference?

    Mike
     
  8. Wendy

    Moderator

    Mar 24, 2008
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    2,535
    SSRs come in AC or DC forms, you can look around. I don't have much experience with stepper motors, so I can't help you there, but I've never heard of a relay being used to drive stepper motors.

    You can compensate SSRs weakness by overrating them by at least X3 the current you need usually.
     
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  9. mpooley

    Thread Starter Active Member

    Mar 3, 2010
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    Thanks to all that replied.
    I have now been told that I can control a relay via the "1 wire" microlan. using the DS2405 chip from maxim.
    The only problem is I cant find a cct diagram anywhere for doing this.
    it's not in any of the data sheets and my googling hasn't helped.

    anyone know how to do this please ?

    Mike
     
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