sequencher

Discussion in 'The Projects Forum' started by TipRing, Jan 24, 2011.

  1. TipRing

    Thread Starter New Member

    Aug 23, 2010
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    OK Guys I know this has been a long drawn out project.
    But I thank all involved.
    Here is the latest drawing does it look ok now.
     
  2. bertus

    Administrator

    Apr 5, 2008
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  3. TipRing

    Thread Starter New Member

    Aug 23, 2010
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    Thats right it would not let me add to that post because of the age.
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    Pictures? Please? I'm a fan of fireworks.
     
  5. TipRing

    Thread Starter New Member

    Aug 23, 2010
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    A freind took this one at my last shoot.
     
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  6. Wendy

    Moderator

    Mar 24, 2008
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    Not that (though I do love a star burst)! The launcher! :D :p
     
  7. SgtWookie

    Expert

    Jul 17, 2007
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    I'm somewhat confused about your use of the bridge rectifier and optocoupler.

    When you connect the "Your Firing System Power" and turn on the switch in the box, it will pull the 555 TR input low. Did you mean for the 555 to be in a one-shot configuration?

    SB1 also will pull the 555 TR input low. Not sure why you have two ways of doing something similar?

    You only show a 12v battery on the 1st page, but elsewhere in the schematic, you show 24v, etc. - where does this power come from?

    You are using DO0 on the 4017 decade counters. This will cause the electric match connected to those outputs to fire when power is first applied - if the 4017's are initialized properly. However, there is no method to insure that the 4017's are reset on power-up, so they will have a random output high.

    Here's an excerpted image from Motorola/ONSemi's MC14017B's datasheet showing how to cascade 4017 counters:

    [​IMG]

    You can use the two diodes and resistor as an AND gate as you've shown on your schematic.

    Note that this schematic does not show initialization logic. Note also that DO0=Q0 on this schematic, and that Q0 is not used on the 2nd and 3rd 4017.

    If the RESET on the leftmost 4017 were pulled high for a moment, it would cause the other two 4017's to reset as well.

    Unless you wish for the 1st electric match to fire immediately when the power is applied, you will not be able to attach drive circuitry to the Q0 of the 1st 4017, nor any of the other Q0's. This gives you 8 decoded outputs per 4017, for a total of 24 outputs.

    You do not show 0.1uF capacitors across the Vdd/GND pins of the ICs. This is OK in the schematic, but you must use them on the actual circuit. You will also need a LARGE on-board capacitor to provide the power to light the matches. Current draw will be quite heavy for perhaps 50mS or so.
     
  8. TipRing

    Thread Starter New Member

    Aug 23, 2010
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    The bridge rectifier is for polarity, and the octicoupler is for isolation.

    there are two ways to activate this is the button is for calibrating speed and the 12-24v input is what the firing system puts out and it could be 100 feet or more away. Yes when it is hit it should run through 1 time.

    the voltage comes from 2 12v batteries. So your saying it won't run like I have it.
     
  9. SgtWookie

    Expert

    Jul 17, 2007
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    I'm wondering why you even need the 12v supply at this end? If the 12v/24v supply is going to be on the range (at the mortar pit/launch pad/etc) the current requirement for the control end will be minimal. You could use very small-gauge wire and it would work.

    Calibrating speed? Do you mean that you will manually step the pyrotechnics through each step, or that somehow the "button of remote start" will be able to adjust the timing of the 555 clock? I don't see a definition for this function in either thread, so I'm wondering what it's about.

    By the way, if it's a mechanical switch, you should be concerned with a phenomenon known as "switch bounce". This will wreak havoc with a scheme to use a mechanical switch as a clock input.

    OK, when the button is hit, then the counters should run through automatically without further intervention? In that case, "The button of remote start" is a "begin sequence" kind of thing; fire a broadside if you will.

    OK, so the 24v can come from the two in series, and the 12v can be tapped off the low side battery. No reason to be lugging more batteries around then you have to.

    I notice that you have an indicator LED for when the match is supposed to fire, but there is no indicator whether the match has continuity.

    Also, you don't show the ground connectors for the electric matches; only the collector outputs from the PNP Darlingtons. Is the ground side of the matches going to be connected to a common rail or something?

    I'm saying that as soon as you apply power to the circuit, there is a 90% chance that you will have three simultaneous firings of matches; if your power supply and wiring can take that load.

    There is no state for the 4017 counters except D09 high where a match won't be energized. DO0 must not be connected to a match circuit on any of the 4017's, and the 4017's must have a function that resets them instantly on power-up.
     
    Last edited: Jan 25, 2011
  10. medix87

    New Member

    Feb 3, 2011
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    hi so how do you insure that a 4017 counter always starts at shot 1 mine seem to be random if you have a diagram that would also be helpful thanks
     
  11. Wendy

    Moderator

    Mar 24, 2008
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    A simple resistor capacitor will reset the sucker on power up. Something like this...

    [​IMG]

    Look at C2 and R5, it is a power up reset. If you feed one of the outputs into the "Reduce Count Input" you can have less than the 25 sequences.
     
  12. medix87

    New Member

    Feb 3, 2011
    3
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    Thanks for the tip that helps a bunch cheers!
     
  13. medix87

    New Member

    Feb 3, 2011
    3
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    ok i finished off a 10 cue sequencer i made with the help of this thread and others http://www.youtube.com/watch?v=VnYzY5e4--E

    its abit messy but i wanted to see if it would work well (which it does) so i will now make a 24 cue sequencer using the AND gate cascading 4017 (with the great tip of adding resistors and caps). So thanks again guys helped me alot!!