trigger pulse delay

Discussion in 'The Projects Forum' started by viveiroscordeiro, Jan 13, 2016.

  1. viveiroscordeiro

    Thread Starter New Member

    Aug 20, 2012
    6
    0
    Hi,
    I'm looking for a simple circuit to do the the following: (pdf graphic attached)
    Whenever a trigger sinal goes off, a pulse is emitted, for a determinate time (+/-1 second or less) ideal this time could be adjusted, but a fix pulse time is OK.
    Do you now any simple circuit to build, or any module to buy?
    This is for controlling a time-lapse slider.
    I have a splitter, opto-isolated, that divide a sinal going from a timer to my camera, so with this simple circuit I could trigger the slider motor during 1 second starting when the shutter is closed, to make shoot-move-shoot. No need for complex motion control, just my timer and camera, or even only my camera as it as an internal timer, and outputs a sinal whenever the shutter is open, and the slider is ready to accept a triggering sinal...
    This would be an incredible help...
    Thanks !
    Best
    Pedro
     
  2. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,544
    1,251
    What you want is called a monostable circuit, or a monostable multivibrator. Very simple, can be done with a 555 timer chip, CMOS logic gates like a 4093, an opamp, relays, vacuum tubes... it's an old idea that's been done with just about every type of electrical technology over the years. The details of your application narrow the field.

    What power is available to run the timer?
    What is the trigger signal? An electrical signal (what voltage), a mechanical switch, etc.
    What does the "switch" output signal go to? Another electronic circuit, a relay, a motor...?

    ak
     
  3. viveiroscordeiro

    Thread Starter New Member

    Aug 20, 2012
    6
    0
    Thanks AnalogKit!
    -The power available is 12 or 5V
    -As trigger I have an optocoupler, being activated by the camera or timer so it will be functioning like a switch.
    -The output sinal as to trigger something like this:
    FET module, input and output totally isolated from each other.
    Input signal voltage: 3V~20V; Input current: about 5mA.
    Output voltage: 5V~36V Current: within 5A, Max.
    (This FET will activate the motor)
     
    Last edited: Jan 13, 2016
  4. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,544
    1,251
    Big motor...

    3V to 20 V input sounds like a solid state relay...?

    What is your skill set in electronics? Do you want to build a small circuit, or buy a module on ebay?

    ak
     
    Last edited: Jan 14, 2016
  5. viveiroscordeiro

    Thread Starter New Member

    Aug 20, 2012
    6
    0
    -The motor is this:
    http://www.conrad.com/ce/en/product...tor-Modelcraft/?ref=detview1&rt=detview1&rb=1
    Max. load current 2.1A-12V
    - I dont have the solid state relay yet, I use a normal one for tests, so the reference I give you was this: http://www.ebay.co.uk/itm/221938484446?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT
    But it can be different if needed.
    My skils:
    I'm not very skilled in electronics, I'm just an Architect and amatour videographer, who like to play with etronics, I now de basic functions of componentes, resistors, transistors etc., and I can do some welding.
    This is the DIE slider I built:

    Now I'm building a smaller one, to traveling, and was thinking to substitute the controller for an Arduino or raspberry pi to do shoot-move-shot (moving the motor only between the time-lapse shoots), but it seems like an overkill, and I'm being lazy to learn some code, I only need to send a pulse to de motor when the camera triggering sinal is't over. The timer of the camera or smartphone is convenient, and I already have a couple of 4N35 optocoupler, being activated by the camera or smartphone (trigger trap application) wen the shutter is open...

    So it could be a module from eBay, or a simple circuit to built...
    Controlling the time of the pulse would be better, but a fixed one is OK, I have made some tests, and 1 or 1,5 seconds is OK to move the slider de distance I need, with this motor, or I can put a diferent gear relation and use a smaller pulse...
     
  6. viveiroscordeiro

    Thread Starter New Member

    Aug 20, 2012
    6
    0
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