Singing Santa circuit

Discussion in 'General Electronics Chat' started by T3553r, Dec 7, 2011.

  1. T3553r

    Thread Starter New Member

    Dec 7, 2011
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    I've got one of those singing Santa toys where you squeeze his hand and he sings jingle bells for about 30 seconds and turns off. Unfortunately he stopped singing all the sudden so I decided to make a small project out of him.

    He's powered by two double aa batteries inside his belly. Inside I found a small circuit that was wired to a switch in his hand. The circuit has a speaker, two transistors, what appears to be a capacitor, and some sort of memory chip where I assume the song is stored.

    I looked around and everything appears to be connected nice and solid. I know the circuit is working because there's a red light in his nose that lights up when you squeeze his hand. Right now when I squeeze his hand the light glows red for a while (what appears to be the duration the song was) but no music :(

    I soldered the speaker to some old headphones to confirm it's integrity and it works fine. Any ideas as to troubleshooting from here? I've read online you can use a circuit from a singing greeting card but I'm not sure how the push button normally closed switch in his hands would be able to trigger the song to play all the way through and shut once the song is over :/
     
  2. T3553r

    Thread Starter New Member

    Dec 7, 2011
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    Any idea how to activate my greeting card circuit for 15 seconds?
     
  3. tracecom

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    Simple things first: did you put new batteries in? It's possible there is enough power in the batteries to light the LED, but not enough to power the speaker.
     
  4. tracecom

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    How do you know it's a normally closed switch? It seems more likely that it would be NO.
     
  5. thatoneguy

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    The square/rectangle chip you see is likely the audio amplifier. On the board, probably the back/trace side, there's more than likely a black blob that contains a COB (Chip On Board) microcontroller (looks like somebody accidentally got a drop of black wax on the board). The black blob (do not disturb) contains all the songs and code for decoding/playing the tunes. Switch in hand can be NO or NC, the controller can work with either type of switch based on how it wakes up from the interrupt. The COB type controllers cannot be re-programmed, when they fail, buy a new item. They are used in everything from Christmas lights to clock radios, though the actual function of the controller varies widely depending on what it is controlling.

    If the output works on headphones, the internal speaker probably just needs to be replaced. Radio Shack sells 1" 32Ω speakers for $2 that would do the trick.
     
    jaygatsby likes this.
  6. T3553r

    Thread Starter New Member

    Dec 7, 2011
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    Thanks for the replies :)

    So I made sure it wasn't the batteries and it still won't sing. Just to clarify the headphone test was to confirm the speaker works. It appears the circuit just won't output the music anymore. Maybe the black wax like blob is the problem maybe it's something else but I have a plan.

    I got a circuit from a singing card that plays when opened. The problem with integrating that into Santa's belly is how to trigger it. Right now the switches in his hands only complete the circuit when pressed. I tested the switch out by hooking it up to a 9v battery and a light. The light illuminated when i was pushing the button (switch) but as soon as I let go it goes out.

    To test out the card circuit I attached a regular toggle switch to the trigger leads. When I flip the switch on it plays as it should. One thing to note is that I am able to leave the switch on without the song playing. Once it ends the song can only be triggered by turning the trigger switch off and on.

    I'm not sure if it's possible to create something that triggers the song when a button is pushed instead of when a switch is flipped?
     
  7. thatoneguy

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    You could create a 555 one shot if and adjust the timeout value to what you need.
     
  8. tracecom

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    Try this: Flip the toggle switch on, and while the song is playing, flip it off. If the song completes playing, then pressing a NO (normally open) momentary contact push button switch will do the same thing.
     
  9. ErnieM

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    Apr 24, 2011
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    It sounds to me like the pushbutton from the original Santa's hand works the same way as the toggle switch, they both close (make contact) to start the song.

    So looks like you can just connect to the existing switch. (And if it doesn't work then nothing wasted).
     
  10. T3553r

    Thread Starter New Member

    Dec 7, 2011
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    Tried using the original push button switch but that only makes the song play until I release the button. When using the toggle instead as requested above the song stops as soon as I switch it off. I think using a button that doesn't complete the circuit when pushed (normally closed?) could work. The 555 one shot might be good too but I'm baffled as to how the old broken circuit was able to be triggered by the push button switch? I'm gonna attach a picture later :)

    Is the 555 one shot easy / inexpensive to build? Radioshack should cover the parts?
     
    Last edited: Dec 10, 2011
  11. tracecom

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    The old circuit had the equivalent of a one shot circuit in it; the new one apparently does not.

    Here is a circuit for a one-shot. With the components shown, the output (pin 3) should stay high for 10 seconds.

    [​IMG]
     
    Last edited: Dec 11, 2011
  12. T3553r

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    Dec 7, 2011
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    Back
    [​IMG]

    Front
    [​IMG]
     
  13. T3553r

    Thread Starter New Member

    Dec 7, 2011
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