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schematics for multi switch 555 I.C. timer/childrens toys

Discussion in 'Electronic Basics' started by mark3, Dec 20, 2005.

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  1. mark3

    mark3 Guest

    Hi,
    Is it possible to build a circuit that can trigger at least
    four interchangeable (R.C.A connection) toys independent of each other;
    using 4 pushbutton toggle switches coupled to a monostable circuit with
    555 I.C. timer and variable D.C power supply, there is one toy that
    uses 9v two that uses 6v and another that uses 3v .I have built the
    D.C. power supply and small monostable 555 timer that can trigger one
    toy at a time via pin 3 through a transistor (548). Are there any basic
    schematics around that could show me how to wire up 4 independent
    trigger switches to 3v, 6vand 9v toys that are incorporated in to the
    one monostable circuit, if not do you have any ideas or schematics that
    might help achieve the desired affect?

    Thankyou
    Regards
    mark
     
  2. Chris

    Chris Guest

    Hi, Mark. You might try this (view in fixed font or M$ Notepad):


    R=1K +3V
    |
    Q=2N3904 or equiv. |
    '---o
    Toy1
    .-----------o
    From 555 |
    ___ |/
    o---o---|___|-o-| Q
    | R | |>
    | .-. | +4.5V
    | R| | | |
    | | | === |
    | '-' GND '---o
    | | Toy2
    | === .-----------o
    | GND |
    | ___ |/
    o---|___|-o-| Q
    | R | |>
    | .-. | +6V
    | R| | | |
    | | | === |
    | '-' GND '---o
    | | Toy3
    | === .-----------o
    | GND |
    | ___ |/
    o---|___|-o-| Q
    | R | |>
    | .-. | +9V
    | R| | | |
    | | | === |
    | '-' GND '--o
    | | Toy4
    | === .-----------o
    | GND |
    | ___ |/
    '---|___|-o-| Q
    R | |>
    .-. |
    R| | |
    | | ===
    '-' GND
    |
    ===
    GND
    (created by AACircuit v1.28.5 beta 02/06/05 www.tech-chat.de)

    All of the components above are available at Radio Shack, Maplin, and
    any hobbyist source. Each of the four transistors above should easily
    sink up to 100mA of current with a 555 power supply voltage of +5V or
    more.

    I'm not sure this is very responsive, though. If you would, could you
    please offer more of a description of what you're doing? Expiring
    minds need to know:

    * What voltage are you running the 555 at?
    * What's "548"? Is that a 2N548, a 2SC548, and NTE548, or what? NPN,
    PNP, darlington, FET???
    * Do you have a reference on the web to your application circuit? If
    not, you might want to try downloading Andy's ASCII Circuit Beerware
    (you owe the author a beer if you meet him). It's available at the
    link above, and can make describing simple circuits on newsgroups much
    easier.
    * What do you mean by "trigger"? Are you just turning on and off the
    battery power to the devices, or do the devices have an external signal
    that turn it on and off? The above assumes you're just turning the
    battery power on and off.
    * Usually, 9V battery-operated devices and ones that use AA and AAA
    batteries use less than 100mA, but devices that use C and D batteries
    may use more. If you don't have a handle on the current draw, please
    at least say what kind of batteries are used for the four devices,
    along with their voltages. Exessive current draw on the transistors in
    the circuit above can let the smoke out.
    * If you're using the 555 as a one shot (triggers and goes on once for
    a press of a pushbutton), you may have issues with the single pulse at
    turn-on of the 555. If that's a problem, there's an easy solution, if
    you ask.

    Please feel free to provide more information.

    Good luck
    Chris
     
  3. ehsjr

    ehsjr Guest

    I'll draw 1 instance for SCR N - you need to repeat it
    for each toy to be controlled. The pushbutton circuit
    is shown for buttons 1,2,3 and N. The inverter circuit
    is also shown - it changes the + signal from the button
    to minus needed to trigger the 555.


    +V ----+-------------------------------------+--- 555 pin 8
    | |
    | PB toy 1 D1 |
    +----o o---------------+--->|---+ |
    | | | |
    | to SCR 1 gate | |
    | PB toy 2 D2 | |
    +----o o---------------+--->|---+ |
    | | | |
    | to SCR 2 gate | |
    | PB toy 3 D3 | |
    +----o o---------------+--->|---+ |
    | | | |
    | to SCR 3 gate | |
    }} }} |
    | | |
    | PB toy N Dn | [1K]
    +----o o---------------+--->|---+ |
    | | |
    Vcc toy N ------+------+ | | +--- To
    | | | [1K] | 555
    [Toy N] [470] | | | pin 2
    | | | | |
    +------+ | | /c
    | | +---| Q2
    [SCR N] | \e BC548
    |\ | |
    | +---[330]---+ |
    /c |
    555 ---[1K]---| Q1 BC548 |
    pin \e |
    3 | |
    Gnd Gnd

    The 470 ohm resistor will keep the SCR conducting even if there
    is brush bounce in the toy's motor.

    How it works: When a pushbutton is pressed, it puts + on the
    gate of its corresponding SCR, causing the SCR to turn on.
    It also turns on Q2 which provides the negative needed to
    trigger the 555. The SCR will remain on as long as Q1
    conducts, and Q1 conducts while the 555 output is high.
    D1 through n can be 1N4148, 1N4001, etc.

    Ed
     
  4. mark3

    mark3 Guest

    Hi Chris, just checking if you recieved my reply email re: 555 IC timer
    /childrens toy ?

    Regards Mark
     
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