Motor (Clockwise for a second, stop, counterclockwise for a second, stop) -- Relays?

Discussion in 'The Projects Forum' started by adamfier, Jun 12, 2009.

  1. adamfier

    Thread Starter New Member

    Jun 12, 2009
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    What I want to accomplish:
    Press a switch-
    Motor spins clockwise for a time, and then stops
    The same motor then spins counterclockwise for a time and then stops
    -END-

    My idea
    I am using a remote control to activate a relay that activates the motor. My thought is that I could run two sets of wires from this relay: the first going to a timed relay of some sort to make the motor spin clockwise for a time (t) and then stop. the second set coming from the relay would go to a delay or something that would wait for (t) and then spin the motor counterclockwise for (t) and then stop.



    I would like to press my button, and the motor turns, pulling a string and lifting a weight, and then the motor turns in the opposite direction and lowers the weight back down.


    Thanks in advance for all of your help. Please be as specific as possible. I am still learning.
     
  2. GetDeviceInfo

    Senior Member

    Jun 7, 2009
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    We put together a quick assembly a few years back where the cord was doubled around a pivoting idler. This idler had a simple opto paddle that counted movement. Count up , then count down. One problem we ran into was at the end, if the cord was slack, a tangle was inevitable. We then sprung the idler against a limit switch which would stop motion as soon as any slack developed in the hoist cord.

    In the final device, the opto was used for both speed regulation and position, and we retained the limit to avoid tangles.

    Because speed was dependant on other functions, our drive was micro controlled to accomodate changing parameters.
     
  3. samuraimarc

    Active Member

    Mar 28, 2009
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    What kind of motor? AC? DC? voltage?
    Are you trying to use electronics or industrial motor controls? I.e. socket timers, starters, cube relays.
    Might be able to help with a little more info.
     
  4. adamfier

    Thread Starter New Member

    Jun 12, 2009
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    It is a dc motor running off of 9v. I want to use electronics

    I plan on making/building a 2 stage time delay. http://home.cogeco.ca/~rpaisley4/LM555.html#20

    However, I want a delay between output 1 and 2.... i.e., output 1, delay, output 2. I think that means that I must use 3 555's.

    Thanks for the help.
     
  5. Chris15

    Active Member

    Apr 15, 2009
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    well to make it go clokwise and couter clock wise is easy, you need a DPDT switch, connect to 4 corner pins together diagonally, (not all together) just the 2 diagonally, then connect your pos and ned to either of the 2 outside legs next to each other, (the ones that have been used to cross) and your motor connedts to the 2 pins left in the middle. so when the switch is in the middle it is off, up is clockwise, down is counterclockwise. as for the timing you can make a small time delay circuit connected in between one of the leads to the motor so when the power id given it will go 'on' for the amount of time u want. if you connect a pot to the time delay circuit you can ajdust the timing.

    Chris
     
  6. Wendy

    Moderator

    Mar 24, 2008
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    You could also use something called an H Bridge. Basically 4 transistors, 2 on, 2 off at any one time, that connect the motor back or forth to the single ended power supply. A solid stage equivalent to a switch. If all 4 transistors are off then the motor doesn't turn.

    It's what a lot of RC electronics use. Need more info?
     
  7. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Two recent posts had reversing motirs, might like to review, kksmith & Gibling. The drawing is a modification from another application. I have a question, did you wish a delay when weight [W ] reached the top? As shown weight stopps when at top, & lowers when sw EF is mom. opened. Operation starts with W holding sw CW open, when UP sw [OUT] is closod long enough for sw CD to close as motor lifts weight, also relay [RY] closes and latches , keeping power on motor. On reaching top W opens sw AB, motor stopps. When IN sw[ Down] is pushed ,Ry is un-lalcher, reversing motor. Questions? ,just ask.
     
  8. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Before I forget H bridge by http://www.solarbotics.net/library/circuits/driver_4varHbridge.html

    At start, both 555 outputs LO , motor off; momentary closure of SW causes a 1.5 sec. pulse at output of first 555, causing motor,M, to rotate clockwise for 1.5 sec. Negative going edge of pulse triggers second 555 for a 1 sec. pulse, causing M to rotate counter clockwise for 1 sec. At end of pulse , both outputs are LO, M stops. Need information on operating voltage & M V & current to select transistors & RM. One 556 could be used, just easier to see operation with 555s. RM eases load on M & H bridge when M is stalled. Make any sense?
    PNP 2.2k's should go to +V or better eliminate all 2.2Ks.
     
    Last edited: Jun 17, 2009
  9. adamfier

    Thread Starter New Member

    Jun 12, 2009
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    Everything looks great. Thanks again for your help.

    What is RM?
     
  10. adamfier

    Thread Starter New Member

    Jun 12, 2009
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    Also, what are the parts with the 1M resistors? the things that look like loops with arrows pointing to the resister?

    Thanks
     
  11. SgtWookie

    Expert

    Jul 17, 2007
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    "RM" is a resistor to limit current through the motor.

    There is only one part labeled "1M" near the far left of the schematic.
    It is a 1 Meg potentiometer (pot) wired as a rheostat (the wiper is connected to one end of the pot).
     
  12. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Thanks Sgt. It looks like the H bridge is prone to " shoot-through", ie, both PNP & NPN in same string, both conduct at the same time.With RM @ 5Ω, current might be about 1.8A on shoot-, with out RM, current could be 9A. Presume this is an intermittant operation, so with transistors rated for 2A or greater, depending on motor, there should be no problem. RM provides another service in providing some bias so that when 555's are HI, they will be able to turn off the PNP's, still a little iffey.Might be a place for a rail to rail driver. HELP!!
     
  13. SgtWookie

    Expert

    Jul 17, 2007
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    "Still a little iffy" on the PNP turn-off doesn't quite cover it. ;)

    BJT 555's have a Darlington output for the high side. You're doing well if you get within 1.3v of Vcc. However, you put the 2.2k pull-up resistors on the bases of the PNP's, but mistakenly ran them to ground instead. I don't think those PNPs are ever going to turn off.

    Going to CMOS 555's would do the trick, if they weren't so limited in source current; 10mA is about the limit.

    It would help to swap out the plain transistors for Darlingtons, like perhaps TIP132 and TIP137; you could then use much higher resistance on the bases. Problem there is you automatically lose around 1v from Vce - both on the high and low sides.
     
  14. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    All the above is true, I measured pin 3, on 555 to vcc today , and yes it is 1.3V. I corrected the 2.2 snafu in the verbage but not on print. Without more inf. on motor ,decided just to let it slide 'till we knew more. With only 9V[ might be battery], can't afford too many losses.plenty of drain already.
     
  15. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    A short socket board simulation & 'believe we have a solution, subject to review.Used a 1k pot for the 555. It took 2V [7-5] to start current flow in LOAD, so should have 1/2V safety factor, with RM would be abt 1V. With motor stall current,& loaded current known , could pick out parts & finish drawing.
    If it is battery operated, could add a TLC555CP, set for 5 sec, controlling MOSFET power switch @ verry low drain.
     
  16. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    I believe this will work now.
     
  17. Wendy

    Moderator

    Mar 24, 2008
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