Lighting circuit for RC baitboat

Discussion in 'The Projects Forum' started by Paul_Over, Dec 14, 2011.

  1. Paul_Over

    Thread Starter New Member

    Dec 14, 2011
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    If possible, I would like some help with designing an LED lighting circuit for a remote controlled baitboat that I am in the process of building.

    The boat is powered by a 12V lead acid battery, and it already has night time illumination lighting - this is controlled by a latching power switch, that feeds 5 LED's.

    The boat has 2 hoppers/bait droppers that are individualy controlled by the forward and reverse actions of a single servo, which is activated by the center/left and center/right actions of one of the transmitter's sticks.

    What I would like to achieve is that when each of the hoppers is activated/opened, it not only opens the hopper, but also flashes the boat's lighting circuit a number of times, before the lighting circuit itself reverts back to it's original position, which would be either permantently on or off, dependant on the current position of the latching switch that is already fitted to the existing lighting circuit.

    I was thinking that it is likely that I would need to break into the servo's circuit with a Y-splitter, and use either another latching or momentary type switch to activate the required secondary circuit, but please bear in mind that I am a complete novice where electronics are concerned.

    There are a few baitboats on the market that already do what I am trying to achieve, and someone has mentioned that flashing the LED's would be done with a 555/556 chip, and the switching over could be achieved by a solid state relay or another 555 chip, but like I said, although I am a very capable solderer, the circuit design itself is well beyond my capabilities at the present time.

    Please also bear in mind that a low power consumption is imperitave for this circuit - any help would be greatly appreciated.
     
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Do you want confirmation that the servo moved, or confirmation that the hopper door opened?

    Two different designs.

    Can you provide a photo of your unit from a few angles? Overall, and especially the moving parts. 3200x2500 resolution, then download irfanview (free image program), open picture in irfanview, pick "Save For Web", then "Max size" of 200kB, and you can attache the pictures to your post without needing an image hosting service.
     
  3. Paul_Over

    Thread Starter New Member

    Dec 14, 2011
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    Hi, thatoneguy.

    Being that the hopper doors are opened by a latch that is pulled by the servo and the doors themselves rely upon gravity to open, confirmation of when the servo is activated or the hopper doors opening is kind of the same thing, although I am trying to steer clear of mechanical devices/micro switches, so I would have to say that the objective is to confirm the servo's actuation by temporarily flashing the boat's illumination lighting serveral times.

    You are right - a picture can say a lot more than a gazillion words, so I have included a few.

    Thank you for your interest.
     
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    How much clearance is there between the Futaba servo horn, and the cover that goes over it?

    Some sort of mechanical switch would be needed to confirm the servo moved.

    A microcontroller could be used to confirm the signal was received, but that may not mean that bait was dropped, and would be much more complicated.
     
  5. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    For lighting ideas, check out Bill_Mardsen's blog on LEDs, lights, flashers and chasers.

    555 timers, LED Flashes, etc.

    Leave some Running LEDs out of the "dump alert" circuit so you can still see it if the circuit fails, or have an extra set of LEDs higher up in the air flash when dumped.


    It would be a matter of having the switch be closed temporarily while the servo horn passes it, which would trigger one of the circuits above.


    Trying to sense the servo signal line is complex, and would need a microcontroller.
     
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  6. Paul_Over

    Thread Starter New Member

    Dec 14, 2011
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    The boat's on/off power switch and charging socket is fitted directly above the servo, leaving minimal clearance when the deck is fitted - around 6-8mm.

    Also, the access to this area of the boat is very limited when the deck is fitted/bonded together, which is partially why I was trying to steer clear of micro switches, and in preference, was hoping to use the signals sent to the servo by way of an additional momentary/latching switch that would be activated by the transmitter's same stick as the hoppers for control. This circuit/PCB could be fitted to the same area of the boat as where the receiver and ESP's are situated, which is fairly easy to access for maintenance.

    Although it cannot be seen, because it is still on my breadboard, but has been tried and tested; this is how the existing lighting circuit is switched on and off - by way of a latching switch from the transmitter's other stick.
     
  7. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    The way R/C works is the three wires, one is power, one is ground, and the middle is signal.

    The signal wire gets a pulse of 1.5mS duration every 20mS to be in the center (this leaves enough time for the other 9 channels to put in their pulses from the transmitter). 0.5mS long pulse makes it swing all the way to one direction, and a 2mS pulse makes it swing all the way to the other direction.

    So a circuit would need to be made that would alert if A) communication was lost (no pulse train) B) pulse was less than 1.4mS duration and C) pulse was greater than 1.6mS duration.

    This could be done with a PIC using a CCP module (capture/compare/pwm), using the capture portion of the peripheral to see how long each pulse was, then change I/O pins accordingly to flash lights.

    I'm not sure of a glitch-proof simple analog method for this.

    I know servo mixers for aircraft are made from microcontrollers, as are the missing pulse alarms to help find the airplane when it crashes.

    I'm not sure if there is one to buy off the shelf that does what you want it to.

    I guess if there is room, you could "Tee" off that servo's line to run a micro-servo (they make them very small these days) to hit switches, but that's still a mechanical solution.
     
  8. Paul_Over

    Thread Starter New Member

    Dec 14, 2011
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    thatoneguy - thank you for the info' again.

    After looking around, I think I could possibly source two individual circuits that will 'somewhat' do what I want them to do, but it will only be by trial or error, and I agree that trying to use the servo signals to control this setup is going to be too complicated for someone like myself that has very little electronics knowledge/experience, and will it be glitch-free?

    Taking the above into consideration, I was thinking along the lines of maybe using a changeover reed switch to switch between the two lighting conditions of the single circuit. The magnet could be mounted to the underside of the existing servo's horn, which would be above the changeover reed switch (or possibly a changeover microswitch if the do such a thing?). When the servo is in it's neutral state, the main lighting circuit would be closed, which would either have a feed to it or not, depending on the state of the latching power switch I have already fitted for turning the boat's illumination lights on and off. When the servo is energised in either direction, that circuit would become open, and the 'flashing' side of the circuit would then become closed at the same time as the hoppers opening. I could build a basic 555 chip circuit to make the LED's flash.

    The problems that I foresee are as follows:

    This would mean running two positive feeds to the LED's, one for each circuit/state; would back-feeding the reed switch or 555 circuit create any problems?

    Also, the servo's movement is pretty fast, and as the servo is only actuated for as long as the transmitter's stick is held left or right of center, it would be a very limited amount of time for the LED's to flash before the servo returned to it's neutral state. I'm sure there is a way around this by using capacitors to elongate the period of time that the LED's flash for, but when the servo returns to neutral, it will re-open this circuit and close the other.

    In your expert opinion, are there any ways around the above, or do you think in trying to keep things simple, I am totally barking up the wrong tree anyway, so to speak?
     
  9. Wendy

    Moderator

    Mar 24, 2008
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    I'm late on this thread, and not quite clear what is needed. Would a PWM detector to on/off switch do the trick?
     
  10. Paul_Over

    Thread Starter New Member

    Dec 14, 2011
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    Hi Bill.

    Quite possibly, but to be honest, I would have no clue where to start with that. Wouldn't any type of changeover or on/off switch that was controlled by the servo's state create the same problem as I listed above - a very limited time for the LED's to flash, because the servo would return to it's neutral state very quickly?
     
  11. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Yes, that would work, and Bill would be the man.

    I'm thinking put a magnet on one of the metal brackets that pivots, so it will get tripped when the horn moves either direction.

    Put a reed relay under that area (under the servo is fine).


    If the circuit has power to it all of the time, you could use one of Bill's chasers to make your bait boat stand out.

    Then a separate 555 on that powered board to blink some different LEDs for 10 seconds after the reed switch was opened/closed.

    Does that make sense, Bill?
     
  12. Wendy

    Moderator

    Mar 24, 2008
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    Yup. It sounds a bit kludgy, but if you read my signature that doesn't bother me a bit. By using two or more reed switches I could see selecting more than one pattern. Just a thought.

    There are some additions I will be making to the main article, LEDs, 555s, Flashers, and Light Chasers , that will simplify some of the projects.

    If you have a specific question post it on this thread, then PM me to attract my attention. Sometimes I get spread a little thin, but I am always willing to help.
     
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