Eenergize an electric motor in one direction for a certain length of time.

Discussion in 'The Projects Forum' started by jsmith24, Mar 27, 2015.

  1. jsmith24

    Thread Starter New Member

    Jul 10, 2013
    16
    0
    Hi all,

    Here's my intent: build a project that will energize an electric motor in one direction for a certain length of time, then stop. Then later, will energize the motor in the opposite direction for a certain length of time then stop. It needs to run off DC only.

    I know I can probably get a DC timer to turn the motor on, and a limit switch can turn it off. What I'm not sure about is how to get the same - or a different - timer to reverse the direction of the motor.

    If anyone knows of a timer can not only power a DC motor, but does NOT need to be connected to AC, I would appreciate the recommendation. I *think* the digital timers don't need AC, and that I can connect a DC source to the input, then power a DC motor from the switched output.

    I'm probably over-thinking, so I came here for tips, advice, et cetera.

    Thanks in advance!

    Jack
     
  2. ScottWang

    Moderator

    Aug 23, 2012
    4,855
    767
    To change the title as :
    Eenergize an electric motor in one direction for a certain length of time.
     
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    I am doing essentially the same thing with a 12ft drive-through motorized gate. The entire system runs on a 12Vdc SLA battery, with solar and standby AC battery chargers.

    I needed a reversible drive, timing, obstacle detection, slowly accelerate, slowly de-accelerate, dead time before reversing, remote radio-control, remote push-button control, etc.

    My approach was to use an Arduino as the controller. My parts count is pretty small; much less than if I had tried to kluge something together with 555 timers and other discrete parts.

    The Arduino does all of the sequencing, motor control, button de-bouncing, timing, obstacle detection, soft start, soft landing, creep to limit, etc, with lots of field tuning to make it operate smoothly...
     
    Last edited: Mar 27, 2015
  4. jsmith24

    Thread Starter New Member

    Jul 10, 2013
    16
    0
    I'd change it, but don't see an option to change the thread title. Also, I appreciate the suggestion, but I know how to make the motor stop, just not how to get it to reverse on a separate timer. :)
     
  5. jsmith24

    Thread Starter New Member

    Jul 10, 2013
    16
    0
    That's much more complicated than I need. I just need to turn a motor in the morning, then in the opposite direction in the evening. It shouldn't require programming an Arduino...though I thought about it.
     
  6. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    Can you have limit switches at both ends of the travel?

    Only inexpensive DC-powered programmable timer I can think off are the battery powered water valves used for irrigation.

    [​IMG]

    I have a couple here with failed motors, but timer part runs fine. Two of them could provide independent morning and evening events, where the duration of each event is settable (to a point: 1min increments.)
     
    Last edited: Mar 27, 2015
  7. ScottWang

    Moderator

    Aug 23, 2012
    4,855
    767
    Any info about the motor AC/DC, V/I?
    I just modified the title as your purpose.
     
  8. praondevou

    AAC Fanatic!

    Jul 9, 2011
    2,936
    488
    1. What's the voltage?
    2. How much current?
    3. How long does it have to run?
    4. Will or must it be limited by an end switch?
    5. How do you want the motor to start, single push button, toggle switch?

    It's not complicated, we just need more infos.
     
  9. jsmith24

    Thread Starter New Member

    Jul 10, 2013
    16
    0
    Actually - I just realized: what I'm looking to do is similar to what a garage door opener does, but I need it in smaller scale, running a small DC motor. If I could get a small enough GDO, all I'd need to do is activ
    1. 12v DC is preferable.
    2.I don't have the motor yet, so not sure about current.
    3. It only has to run maybe less than a minute.
    4. It would most likely have to be limited by a switch...that was my original thought, anyway...
    5. The motor would start from a timer, most likely digital.

    Thanks!

    jack
     
  10. praondevou

    AAC Fanatic!

    Jul 9, 2011
    2,936
    488
    What happens if after the minute the end switch is not reached? When the next timer impulse comes does it turn in the opposite direction anyway?
    Is the end switch more like a protection device? In that case you might not even need the 1min timer.
    What do you think comes from the digital timer? A single positive pulse? This digital timer is supposed to be a real time clock, correct?
     
  11. WBahn

    Moderator

    Mar 31, 2012
    17,777
    4,804
    You are talking two not-completely consistent sets of criteria. Do you want the motor to run for a specific amount of time, or do you want the motor to run for a specific amount of action. You use a timer for the former and limit switches or some other type of sensor for the latter. Take the garage door example -- when you operate the garage door you want the system to run until a specific action as been achieved (the door fully opens or the door fully closes) and NOT for the system to run for a specific amount of time.

    It would help us help you if you provided more details on the problem you are trying to solve, not just bits and pieces regarding how you think you need to solve it. Often we tend to get mired down and invested in an answer that we forget to keep in mind what the question was.
     
Loading...