Model Toy LEDs and Sound Wiring?

Discussion in 'The Projects Forum' started by HvEdtg83, Dec 19, 2013.

  1. HvEdtg83

    Thread Starter New Member

    Dec 19, 2013
    The objective is to take two store bought figurines and to have a red LED implanted in the chest area of one of them that illuminates when it is in close proximity to the other figurine.
    I am trying to have the circuit as unobtrusive as possible while still being technically correct and safe.
    I would like to offload some of the potential "obvious-ness" of the circuit/battery. I think having a secondary item (maybe a tree or car) that is related to the character, and then putting the circuit and battery in that would accomplish this. I could then install a wiring harness inside of the figure that would terminate with a spade connection at the underside of it. This could then be connected to the secondary item to power the mechanism when the two figures are close enough to trigger it.

    My plan is to:
    - Use a small diameter drill bit to *slowly* create the outline of the heart on the first figurine --------> about 1/32 deep
    - Use a thicker drill bit in the center of the heart shape to make room for the LED circuit
    --------> about 13/16" deep
    - Use a smaller drill bit to run the wires from the back of the LED cavity (that I created with the thicker drill bit) down to a terminal implanted in the figurine foot
    - The heart shape will be covered by either translucent paper or I might use a flexible cutting board to cut the shape
    - The figurines are in the mail (should have them Monday) and are made of PVC so they should be pretty easy to work with
    - Dimensions are 2.2"x 2"x 4.4" so they are fairly small

    I considered doing this multiple ways but it seems that a reed switch would be appropriate; this would allow me to put a magnet in the second figurine that would close the circuit and illuminate the LED when they are in close proximity to one another.

    Do you think a magnetic hall effect sensor might be better considering the size limitations? I would like the circuit to consist of nothing but the LED, the resistor, the battery, and the as yet to be determined magnetic trigger. Would using a magnetic hall effect sensor require an additional component in the form of a relay?
    Are there any wireless solutions to this? I know it's possible by using coils of wire but that would be impractical and impossible to conceal. Perhaps you are aware of other options in that area.
    To make it even more complicated (haha) I was also considering having a 9V recording module (capable of playback) that would be triggered when the circuit is closed. I could record a sound clip of the character that plays at the same time the heart (red LED) illuminates.

    I am fairly new to the world of electronics but have solid experience in soldering and can be as patient as it takes to do it right.
    Thanks for any suggestions
  2. MaxHeadRoom


    Jul 18, 2013
    There are Honeywell various types of small proximity sw's SS4xxx line. Bi-polar, Uni-polar and latch.
    The latch type will turn on and stay on until an opposite pole magnet turns it off.
    Reed switch tend to be larger.
  3. wayneh


    Sep 9, 2010
    Define what you mean by "close proximity". When I read your post, I was picturing ~1 ft. Anything you do with a magnet will be in the range of <1", probably more like 0.1", or essentially touching. RFID comes to mind for this, but is a lot more complex than you want.
  4. MaxHeadRoom


    Jul 18, 2013
    I have used the Honeywell SS4xx series bipolar latch types with a 5mm dia button magnet, range is around 10-12mm.
  5. inwo

    Well-Known Member

    Nov 7, 2013
    An ir pair might be a simple way.
    Or ultrasonic.
    Thinking one way, as posted!

    If it has to be noise immune it will get complicated fast.