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

[mark3]

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

 

[Chris]

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

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

 

[ehsjr]

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

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

 

[mark3]

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

Regards Mark