1. Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
    Dismiss Notice

Solenoid driver

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by earckens, Oct 1, 2016.

  1. earckens

    earckens Member

    Joined:
    Aug 25, 2016
    Messages:
    430
    Likes:
    7
    Location:
    Ghent, Belgium
    Drawback again is that you have to reset the switch back to "neutral", or center position each time after having pressed the pushbutton.

    Sorry for the nitpicking :cool:
     
  2. chemelec

    chemelec Well-Known Member

    Joined:
    Apr 4, 2004
    Messages:
    2,123
    Likes:
    77
    Location:
    Hedley, B.C. Canada
    THERE IS NO PUSH BUTTON!
    THIS DPDT SWITCH IS ALSO REPLACING That PUSH BUTTON!
     
  3. alec_t

    alec_t Well-Known Member Most Helpful Member

    Joined:
    Jul 10, 2011
    Messages:
    9,315
    Likes:
    1,230
    Location:
    Cardiff, Wales
    How about this? It needs one such circuit per turnout, but does enable an ON-ON SPDT toggle switch to be used both to trigger a pulse (about 0.6 sec with the components shown) and to provide the required direction indication.
    TurnoutSolenoidSwitcher.PNG
     
    Last edited: Oct 13, 2016
    • Like Like x 1
  4. dave

    Dave New Member

    Joined:
    Jan 12, 1997
    Messages:
    -
    Likes:
    0


     
  5. earckens

    earckens Member

    Joined:
    Aug 25, 2016
    Messages:
    430
    Likes:
    7
    Location:
    Ghent, Belgium

    Sorry chemelec, I assumed you still used the circuit in upload here.

    Now how should it look like?
     

    Attached Files:

  6. earckens

    earckens Member

    Joined:
    Aug 25, 2016
    Messages:
    430
    Likes:
    7
    Location:
    Ghent, Belgium
    Impressive! Where do you get that program from, what is that?

    However, one circuit per turnout? Not economical I think, and centralisation is important to facilitate later extensions, expansions, automation projects,..
     
  7. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

    Joined:
    Oct 30, 2010
    Messages:
    9,963
    Likes:
    1,099
    One circut would not be too bad once in PCB form. If you need 50 TAs to be conrolled multiplexng can be used or a large I2c bus where each driver can control 16 things. More difficult than it sounds. Nonetheless you can stil multiplex with a high and low side driver. You can multiplex the inputs too. You could store the state in FRAM. The micro does the pulsing too. With two 16 chnanel I2C output chips you can have 250 ish solenoids with 32 driver chips and if you want you can control with I2C and a couple of chips. 16 bits can be reduced to 4 with a priority encoder. So about 8 bits for about 250ish solenoids.
     
  8. chemelec

    chemelec Well-Known Member

    Joined:
    Apr 4, 2004
    Messages:
    2,123
    Likes:
    77
    Location:
    Hedley, B.C. Canada
    Still Requires the Center Off Switches and it will Work but Costs more since you need one of these circuits for each set of Solenoids.
    Also the Heat in the Mosfet will Increase as the Gate Voltage Decreases.
     
  9. chemelec

    chemelec Well-Known Member

    Joined:
    Apr 4, 2004
    Messages:
    2,123
    Likes:
    77
    Location:
    Hedley, B.C. Canada
    See POST 70, But Where it Says Trigger, That is just the Terminals on the PCB.
    They Now Connect to the DPDT Switch, which Replaces the Push Button.
     
  10. alec_t

    alec_t Well-Known Member Most Helpful Member

    Joined:
    Jul 10, 2011
    Messages:
    9,315
    Likes:
    1,230
    Location:
    Cardiff, Wales
    It's LTspice, a free download from Linear Technology.
     
  11. alec_t

    alec_t Well-Known Member Most Helpful Member

    Joined:
    Jul 10, 2011
    Messages:
    9,315
    Likes:
    1,230
    Location:
    Cardiff, Wales
    No, it doesn't. Current pulse lasts only while C1 or C2 is charging.
    MOSFET dissipation is ~8W for ~60mS, once per actuation of the solenoid. So average power is negligible. No heatsink necessary.
     
  12. earckens

    earckens Member

    Joined:
    Aug 25, 2016
    Messages:
    430
    Likes:
    7
    Location:
    Ghent, Belgium
    Great!! One switch per turnout, no pushbutton,
    Sorry for the confusion chemelec! Thanks for your help.
     
  13. earckens

    earckens Member

    Joined:
    Aug 25, 2016
    Messages:
    430
    Likes:
    7
    Location:
    Ghent, Belgium
    Great! Would the SPDT switch (ON)-centerOFF-(ON) switch not have to be one where the center position is the standard rest position?
     
  14. earckens

    earckens Member

    Joined:
    Aug 25, 2016
    Messages:
    430
    Likes:
    7
    Location:
    Ghent, Belgium
    alec_t, your proposal requires one pcb with components per turnout: this is not only more expensive, it would also require 3 wires from the control panel to each turnout, same as with a centralised solution (chemelec).
     
  15. earckens

    earckens Member

    Joined:
    Aug 25, 2016
    Messages:
    430
    Likes:
    7
    Location:
    Ghent, Belgium
    Case 1: SPDT ON-ON switches cost €2.23/10, plus the DPDT pushbuttons @ €3.84/10 versus Case 2: DPDT (ON)-centerOFF-(ON) switches that cost €6.80/10. Case 1 also requires more wiring, so cost still higher. Chemelec, your last proposal is the best.
    Except in case 2 I have to provide LED feedback on turnout position because a center-off switch does not show that.
    In any case, thank you all for your thinking, Erik
     
  16. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

    Joined:
    Oct 30, 2010
    Messages:
    9,963
    Likes:
    1,099
    Something I tried to post from my cell earlier in the week didn;t post for whatever reason.

    The general idea is to matrix the switches, so a 16 x 16 matrix could control 200+ solenoids (exact number not 255 because of 0,0 is an off condition.
    You could design the board to accommodate 16 high side drivers and 16 low side drivers. To save $, don't populate. If you need 16, use a 4 x 4 matrix. If you need more start populating drivers. e.g. 4 x 5 or 5 x 5.

    The number of bits can be reduced from 32 to 8 if you use a 4 line to 16 line decoder (not sure if they are made), but I think they are.

    One bad thing is that the high current lines are run.

    An I2C BUS to I/O port may be able to control them.

    Keep the state of the switch in FRAM which can be I2C based. No batteries are required and should have an unlimited lifetime.

    Another problem is how to say use the state to activate a crossing light. Well, if you need it, hopefully you can use a limit switch.
     
  17. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

    Joined:
    Oct 30, 2010
    Messages:
    9,963
    Likes:
    1,099
    In terms of activation, you can multiplex that too, and save on ports. Look up a typical keypad. Analog Devices has an IC that will decode a huge keypad to off load processor work.
     
  18. earckens

    earckens Member

    Joined:
    Aug 25, 2016
    Messages:
    430
    Likes:
    7
    Location:
    Ghent, Belgium
    KeepItSimpleStupid, as I understand it your idea of a matrix is good, except I do not see how you replace DPDT-center-off switches in there.
     
  19. chemelec

    chemelec Well-Known Member

    Joined:
    Apr 4, 2004
    Messages:
    2,123
    Likes:
    77
    Location:
    Hedley, B.C. Canada
    earchens, I think my design is about the simplest overall, but I leave the final decision to you.

    If you needed a PCB, I could do one up for you and mail it to you.
    No Charge!
     
  20. earckens

    earckens Member

    Joined:
    Aug 25, 2016
    Messages:
    430
    Likes:
    7
    Location:
    Ghent, Belgium
    Chemelec, I agree with you: your design is just the best and will be used on my layout; all here have contributed so much, and in the end a lot come out of here. This board has given me so much in terms of information, friendship, help, sociability and feedback.. I feel in debt to you all.
    Your offer of a pcb I gladly accept, I appreciate it a lot but I would like to know how I can return the favour: pm me anytime, I gladly reply.
    Have a good day,
    Erik
     
  21. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

    Joined:
    Oct 30, 2010
    Messages:
    9,963
    Likes:
    1,099

Share This Page