Swicthing device

[John Simpson]

Can you help me?

I am constructing a type of children's toy and need some help.

I have four switches situated in a circle each one located at a cardinal
point. A rotating arm spins in the centre. When the arm rotates to become
situated in front of a switch, I require the switch to be turned on, then as
the arm passes to be turned off. The rotating arm will spin at fluctuating
revolutions. The end of the arm and the switch are very close to each other,
separated by only a fraction of an inch (1/16th +or-).

I really do not want a mechanical solution, basically because of friction. I
did consider some sort of triggering device like infrared or laser, if that
would be possible, but of course the action must not interfere with any of
the other switches until it is their turn.

Can any one offer me a possible solution - a circuit, or whatever? I would
be so extremely grateful.
Last pioint, I am electronically inept and am barely able to solder two
wires together (well not strictly true, but very close!)

Thank you very much

John Simpson

______________________________
the way to enlightenment is with a torch!

 

[KLR]

On Sun, 16 Nov 2003 14:39:36 -0000, "John Simpson"
<john@johnas.free-online.co.uk> wrote:

Can you help me?

I am constructing a type of children's toy and need some help.

I have four switches situated in a circle each one located at a cardinal
point. A rotating arm spins in the centre. When the arm rotates to become
situated in front of a switch, I require the switch to be turned on, then as
the arm passes to be turned off. The rotating arm will spin at fluctuating
revolutions. The end of the arm and the switch are very close to each other,
separated by only a fraction of an inch (1/16th +or-).

I really do not want a mechanical solution, basically because of friction. I
did consider some sort of triggering device like infrared or laser, if that
would be possible, but of course the action must not interfere with any of
the other switches until it is their turn.

Can any one offer me a possible solution - a circuit, or whatever? I would
be so extremely grateful.
Last pioint, I am electronically inept and am barely able to solder two
wires together (well not strictly true, but very close!)

Thank you very much

John Simpson

______________________________
the way to enlightenment is with a torch!


if its going to be used in the light - 4 photocells might be the go

 

[Mike Harding]

On Sun, 16 Nov 2003 14:39:36 -0000, "John Simpson"
<john@johnas.free-online.co.uk> wrote:

I am constructing a type of children's toy and need some help.

I have four switches situated in a circle each one located at a cardinal
point. A rotating arm spins in the centre. When the arm rotates to become
situated in front of a switch, I require the switch to be turned on, then as
the arm passes to be turned off. The rotating arm will spin at fluctuating
revolutions. The end of the arm and the switch are very close to each other,
separated by only a fraction of an inch (1/16th +or-).

I really do not want a mechanical solution, basically because of friction. I
did consider some sort of triggering device like infrared or laser, if that
would be possible, but of course the action must not interfere with any of
the other switches until it is their turn.

Magnetic:
Reed switch (DSE P7856)
Hall effect switch (Jaycar ZD 1902)

Opto:
Slotted opto coupler
photodiode (DSE Z4804)
phototransistor (DSE Z3022)

Things like proximity sensors may also work.

If you can mount a magnet on yout spinning arm and the
speed is not too great the reed switch may be your best
bet, providing you don't want to switch lots of current the
reed switch is a one part solution.

Mike Harding

 

[Rob]

"Mike Harding" <mike_harding1@nixspamhotmail.com> wrote in message
news:h0nfrv4cgo5lquupf5abeifljab18o57m9@4ax.com...

On Sun, 16 Nov 2003 14:39:36 -0000, "John Simpson"
john@johnas.free-online.co.uk> wrote:

I am constructing a type of children's toy and need some help.

I have four switches situated in a circle each one located at a cardinal
point. A rotating arm spins in the centre. When the arm rotates to become
situated in front of a switch, I require the switch to be turned on, then
as
the arm passes to be turned off. The rotating arm will spin at
fluctuating
revolutions. The end of the arm and the switch are very close to each
other,
separated by only a fraction of an inch (1/16th +or-).

I really do not want a mechanical solution, basically because of
friction. I
did consider some sort of triggering device like infrared or laser, if
that
would be possible, but of course the action must not interfere with any
of
the other switches until it is their turn.

Magnetic:
Reed switch (DSE P7856)
Hall effect switch (Jaycar ZD 1902)

Opto:
Slotted opto coupler
photodiode (DSE Z4804)
phototransistor (DSE Z3022)

Things like proximity sensors may also work.

If you can mount a magnet on yout spinning arm and the
speed is not too great the reed switch may be your best
bet, providing you don't want to switch lots of current the
reed switch is a one part solution.

Mike Harding

What is the max speed for reed switches? I thought the make / release times
were in the ms second range (for some reeds anyway).
Am I imagining it or was there an ignition circuit based around a reed(s) in
a distributor a couple of decades back?

 

[Mike Harding]

On Mon, 17 Nov 2003 17:26:17 +0800, "Rob" <rds2665@yahoo.com.au>
wrote:

If you can mount a magnet on yout spinning arm and the
speed is not too great the reed switch may be your best
bet, providing you don't want to switch lots of current the
reed switch is a one part solution.

What is the max speed for reed switches? I thought the make / release times
were in the ms second range (for some reeds anyway).

You need to check the data sheet for this info. really but
it's a mechanical switch, although a small one with very
limited contact travel, so I would guess around the 5mS
mark?

Mike Harding