Pump, trigger 555 circuit

Discussion in 'The Projects Forum' started by highseraphim, Oct 17, 2011.

  1. highseraphim

    Thread Starter New Member

    Oct 17, 2011
    4
    0
    I'm working on a trigger circuit for a 'burst fire' toy laser.

    I have a toy gun with two electronic actions.
    The first is the pump (It's a toy shotgun)
    the second is the trigger.

    I want to design a circuit that will do two primary things
    1. Fire once per pump
    2. Fire a short burst.

    So it would be pump, trigger ( 500mS burst), pump, trigger (burst) ect.

    Holding the trigger shouldn't have any response beyond the initial burst.
    Pulling the trigger multiple times without pumping should have no effect.

    I have a 555 with the trigger capacitively coupled to it that makes an effective one shot output but you can pull the trigger many times and get it to rapidly fire.

    Thanks!
     
  2. highseraphim

    Thread Starter New Member

    Oct 17, 2011
    4
    0
    bump..........
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    How many rounds in a burst?
    What timing between rounds?
    What voltage are you working with, and what battery type?
     
  4. highseraphim

    Thread Starter New Member

    Oct 17, 2011
    4
    0
    The burst is a single round. 500mS works well. That's what I'm doing right now with the 555 timer.

    I'm using two AA batteries. I could switch to a 9V but the AAs drive the 555 and the laser just fine so I would like to continue using those.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You have to realize who you're writing to. The M16A2 has a "burst" mode, it fires three rounds per trigger pull at a 750 rounds per minute cyclic rate of fire.

    When you wrote:
    I naturally assumed you wanted both "SEMI" and "BURST" modes.

    What is the exact part number of the 555 timer that you are using? It should be something like TLC555N and possibly more letters after that. A standard LM555/NE555 won't work properly with only 3v for a supply.
     
  6. highseraphim

    Thread Starter New Member

    Oct 17, 2011
    4
    0
    Yes yes... that makes sense. Sorry about the confusion. Since I've placed a laser in the gun, a burst meant a burst of light or one 500mS continuous beam.

    I'll get the numbers for the 555 after work but it is working well right now for the first part of the circuit. When I pull the trigger, I get a 500mS burst of light and have to re-pull the trigger to get it to fire again. (Semi-auto?)

    Now, I'm considering using a capacitive 'charge' circuit when I pump the gun. This charge circuit would allow the 555 to be active for one use.
    This is the part that I am not quite sure of.
     
  7. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    OK, so post the circuit of what you have now, and we'll go from there.

    I'd already drawn something up, but it was for what I term "burst (1 to 4 rounds fired)", which would not be suitable for a pump-action shotgun.
     
Loading...