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  • Advice on heater

    I have a 1972 mini clubman. Its heater system works via 3 controls - it has two push pull cables, one for the heater tap opening and one to send the air from the cabin to the screen. it also has an on/off electrical switch. Thats it.
    I have 3 options and im wondering which was people would go...

    First is keep the controls as is and keep it manual. This will mean fabricationg a new mounting point for them as my screen will be where the current controls are.

    Second option is to use fb on screen by use of solenoids, but from what ive read controlling solenoids hasnt been mastered yet? Can anyone point me to a website with solenoids which may work?
    This option has two categories
    -Complete climate control - set temperature and forget (fb controls heater tap)
    -Or manual up/down increment buttons on screen to control heater tap.

    Is the second option at all possible or best to just stick with the manual route?

    Thanks
    My baby is done ...Go the soarer

  • #2
    Personally, from your description, I'd use solenoids, but skip the computer control. 1 button & 2 rocker switches......
    Are your controls actually all-or-nothing? Most that use cables have some range of adjustment, but that would preclude you from using a solenoid to control them, you'd need a stepper motor or similar.

    I'm not sure why you assume you can't control a solenoid with the FB? Output1->Relay->'noid extend, Output2->relay->'noid retract. (assuming latching solenoids)
    A stepper motor is only marginally more difficult, using PWM (which seems to be even better supported on the v6)

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    • #3
      I would think you would want to use linear actuators instead of solenoids. You will move the cable X distance and hold it there. This is what a linear actuator is designed to do. A solenoid, on the other hand, is designed to extend and retract quickly. To keep a solenoid extended you have to keep power applied to it. Not so with a linear actuator--remove power and it stays where you left it.

      A linear actuator also operates more slowly that a solenoid--desirable for moving cable-operated heat & a/c controls.
      Thanks,

      Dan

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      • #4
        How big of a throw is it for the cables? Like if you pull the cable X cm's, it goes from being fully opened to fully closed?

        If it is a relatively short distance, then you can also use servos and PWM it. If that is not an option, then I agree with linear actuators. Little harder to setup and more expensive, but will work. Solenoids seem like more of a last resort.
        Fusion Brain Version 6 Released!
        1.9in x 2.9in -- 47mm x 73mm
        30 Digital Outputs -- Directly drive a relay
        15 Analogue Inputs -- Read sensors like temperature, light, distance, acceleration, and more
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        • #5
          A key issue is the force needed - unless you can replace the valve & flap with modern controlled equivalents (pneumatic or electric).
          If too heavy, geared stepper motors (servos) etc may be cheaper if required.



          Fan speed is usually changed thru resistors. You should be able to add a 3 speed resistor pack and switch without too much trouble. (Oh - it's a Mini - scrub the last "too"; else scrub out from without.)

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          • #6
            Hmm ok, the throw is around an inch. One cable is complete open complete close, and the other for the tap is incremental. How much more expensive would a linear actuator be?
            Would I be possibly better off trying to retro in an electric/vacuum water tap maybe?
            Cheers for the responses.
            Last edited by Seifer; 06-26-2011, 04:37 PM.
            My baby is done ...Go the soarer

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            • #7
              Would trying to adapt something like this be possible or is that heading into analog outputs?
              Last edited by Seifer; 06-26-2011, 07:36 PM.
              My baby is done ...Go the soarer

              Comment


              • #8
                Seifer - are you intending to actuate the flap & valve direct rather than the cable?
                [IE - much less force; rotational actuation only; remove cluttering cables and assembly (though OEM setup is nice as a fallback...).]

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                • #9
                  That is an electronic heater tap which appears to have the solenoid built in to it, i'm assuming it just responds to the input from the potentiometer.
                  Im fine with using a cable, i just figured an electronic tap would be simpler. The actual flap for moving the air from the cabin to the windshield would still operate via a cable.
                  Last edited by Seifer; 06-27-2011, 08:53 PM.
                  My baby is done ...Go the soarer

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                  • #10
                    I guess what im asking there is can fb output the equivalent of a potentiometers? ie via multiple relays?
                    Last edited by Seifer; 06-27-2011, 08:17 PM.
                    My baby is done ...Go the soarer

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                    • #11
                      Have you tried using a heavy duty servo? I have used the MG995 servo for heater flaps on a rusty cable and it worked well. Just make sure you get the "original" TowerPro version as the fake ones are terrible.

                      The FB has PWM so you should be able drive the servo directly. This servo needs 7v for max power so you might need to have an alternative power supply.

                      There are plenty of hobby fittings that can be used to connect the servo to the flaps, you just might need a custom bracket that's all.

                      Just a thought

                      Comment


                      • #12
                        Originally posted by Seifer View Post
                        I guess what im asking there is can fb output the equivalent of a potentiometers? ie via multiple relays?
                        If you want to output a variable voltage, use PWM through a low pass filter. That's how it is done. If you want variable resistance, then you will need a resistive ladder with switched outputs.

                        Originally posted by customGadz View Post
                        Have you tried using a heavy duty servo? I have used the MG995 servo for heater flaps on a rusty cable and it worked well. Just make sure you get the "original" TowerPro version as the fake ones are terrible.

                        The FB has PWM so you should be able drive the servo directly. This servo needs 7v for max power so you might need to have an alternative power supply.

                        There are plenty of hobby fittings that can be used to connect the servo to the flaps, you just might need a custom bracket that's all.

                        Just a thought
                        The FB will work with 7v, but then you would need to switch your other relays over to 5v instead of 12v. Or just find a 12v servo.
                        Fusion Brain Version 6 Released!
                        1.9in x 2.9in -- 47mm x 73mm
                        30 Digital Outputs -- Directly drive a relay
                        15 Analogue Inputs -- Read sensors like temperature, light, distance, acceleration, and more
                        Buy now in the MP3Car.com Store

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