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Help me find a switch that moves on or off — Parallax Forums

Help me find a switch that moves on or off

ReachReach Posts: 107
edited 2013-11-12 12:52 in General Discussion
Is there a switches that move on and off when controlled by a digital signal? In other words when I turn the switch on with my hand then later turn it off with the propeller I wish for the switch to move to the off position. Hope this makes since. Thanks...

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2013-11-04 08:25
    Yes, but they're large and expensive and need significant power to activate the solenoids that move the switch. It's much easier and more efficient to use an electronic switch that's controlled by both your "digital signal" and a mechanical switch. What do you want to control and how do you want the switch to behave? What kind of feedback (like an LED indicator light) do you want to use?
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-11-04 08:27
    Having a latching relay shared by any manual switch and a digital device will do the job nice and cleanly. These use pulses to turn on and off the device, so the mechanical side are just push buttons.
  • ercoerco Posts: 20,256
    edited 2013-11-04 08:34
    You could make one pretty easily using a servo and a slide switch, toggle switch, or regular wall switch.
  • ReachReach Posts: 107
    edited 2013-11-04 08:36
    The feedback happens when the switch moves on / off [ visual ]. I see this gizmo as a iPad talking via Bluetooth to the propeller that in turn controls a few switches that physically moves on and off.
  • ercoerco Posts: 20,256
    edited 2013-11-04 08:40
    And then there's
  • ReachReach Posts: 107
    edited 2013-11-04 08:46
    Awesome video !
  • FranklinFranklin Posts: 4,747
    edited 2013-11-04 16:33
    Sorry to continue the off topic videos but....http://www.youtube.com/watch?v=UOn4gxj2Dso (erco started it!)
  • jmgjmg Posts: 15,173
    edited 2013-11-04 17:07
    Reach wrote: »
    Is there a switches that move on and off when controlled by a digital signal? In other words when I turn the switch on with my hand then later turn it off with the propeller I wish for the switch to move to the off position. Hope this makes since. Thanks...

    If you want something largely pre-packaged, the simplest, mass market form close to this, is the one found in car locking.
    Look for 5 wire/Master Central Locking Door Motor
    That gives latching action, and digital control, with visual indication.
    To add manual local control, just add a centre sprung toggle, or 2 push buttons.
  • kwinnkwinn Posts: 8,697
    edited 2013-11-04 17:12
    Some of the latching relays used in lighting systems can also be switched manually and they generally require relatively low power to switch electrically.
  • PoundSign2PoundSign2 Posts: 129
    edited 2013-11-04 20:53
    Having a latching relay shared by any manual switch and a digital device will do the job nice and cleanly. These use pulses to turn on and off the device, so the mechanical side are just push buttons.

    This.
  • jmgjmg Posts: 15,173
    edited 2013-11-04 22:26
    tonyp12 wrote: »

    Nice looking part.

    However, one of my peeves with LATCHING Relays in general, is they forget to include a sense contact.

    If they were serious about energy savings, a small-signal contact that let users sense when the unit had moved, would allow minimal possible energy.
  • kwinnkwinn Posts: 8,697
    edited 2013-11-04 22:47
    jmg wrote: »
    Nice looking part.

    However, one of my peeves with LATCHING Relays in general, is they forget to include a sense contact.

    If they were serious about energy savings, a small-signal contact that let users sense when the unit had moved, would allow minimal possible energy.

    Douglas Lighting has latching relays with sensing contacts. Of course they cost a bit more than $4.00.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-11-05 09:56
    While the conceptual aspect of how the switch presents itself is elegant, the construction could be challenging and expensive.

    By using a latching relay, you could have a slide that works as the equivalent of a push button to toggle on. If the slide was spring loaded, a release from an off signal could return it to the original off position, and physically touching the on position my have it slide back to off while generating another pulse to the relay.

    That would be a lot more energy efficient and maybe more compact that having an electro-mechanically driven slide. A spring would just stretch to the on position, and would release to the off.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-11-05 10:03
    jmg wrote: »
    Nice looking part.

    However, one of my peeves with LATCHING Relays in general, is they forget to include a sense contact.

    If they were serious about energy savings, a small-signal contact that let users sense when the unit had moved, would allow minimal possible energy.

    NOT entirely true about the sense contact.
    There are two kinds of latching relays... one wire that requires some outside feedback to determine an on or off status,

    And two wire latching relays that have one wire to pulse to ON and another wire to pulse to OFF that should not require a feedback set up.

    In general, the two wire latching relays are made for higher amperage switching and two separate coils are required to fully engage contacts properly in opposite directions. The single wire units somehow internally toggle the motion.
  • jmgjmg Posts: 15,173
    edited 2013-11-05 13:27
    And two wire latching relays that have one wire to pulse to ON and another wire to pulse to OFF that should not require a feedback set up.

    I'm talking about energy used, not basic operation.
    Sure, they can work with a fixed pulse, but if you can terminate the pulse early, you can save energy.
    That can translate into a lot of added battery life.
  • ercoerco Posts: 20,256
    edited 2013-11-05 17:35
    tonyp12 wrote: »

    Tony wins IMO for the coolest & cheapest switch around. I'll get two just 'cuz MAYBE I'll use them someday. You could have l,ots of fun with that, making something like a self-switching Useless box with an ultrasonic sensor and flips itself when it detects your hand approaching.
  • AJ-9000AJ-9000 Posts: 52
    edited 2013-11-05 17:40
    I have a Subaru and the power door locks look like electrical rocker switches but are motor actuated and mechanically attatched to the locks. They also use an electrical switch to monitor whether they are locked or not.


    Here are some links on auto power locks;

    http://auto.howstuffworks.com/power-door-lock3.htm

    These kind are simple and directly driven by a motor;

    http://www.ebay.com/bhp/car-door-lock-actuator

    http://en.wikipedia.org/wiki/Power_door_locks
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-11-06 11:19
    jmg wrote: »
    I'm talking about energy used, not basic operation.
    Sure, they can work with a fixed pulse, but if you can terminate the pulse early, you can save energy.
    That can translate into a lot of added battery life.

    Well, one could wire a feedback loop that would do that as well. Or one might statistically determine a pulse length that is adequate. There is always something left for engineers to resolve. Most generic parts are exemplars, not the ideal for a given application.
  • ReachReach Posts: 107
    edited 2013-11-12 12:52
    It seems like I am going to X-out this project since no one makes a small movable switch that is cheap. Small circuit beakers will do the job fine.
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