Flip-flop states with NO power

[Durall]

I understand that a flip-flop will toggle between states when a button
is pressed. I'd like to know though, will it hold state with NO power?

I have an led that I'd like to power with 4 'D' batteries. The first
time that I push the button, I'd like the LED to stay on. The second
time that I push the button the LED will go off. The Flip-flop circuit
will lose power too. The next time I push the button, I'd like the LED
to flash, say 3 times/second. 4th Push, off again. Circuit loses power
again. Goto first push.

Should I just step away from the soldering iron and get some fresh
air?

 

[mike]

I understand that a flip-flop will toggle between states when a button
is pressed. I'd like to know though, will it hold state with NO power?

I have an led that I'd like to power with 4 'D' batteries. The first
time that I push the button, I'd like the LED to stay on. The second
time that I push the button the LED will go off. The Flip-flop circuit
will lose power too. The next time I push the button, I'd like the LED
to flash, say 3 times/second. 4th Push, off again. Circuit loses power
again. Goto first push.

Should I just step away from the soldering iron and get some fresh
air?

Gotta have some memory somewhere. Mechanical switch memory,
semiconductor memory, past-life memory...
Use a low power flip-flop and leave it powered on all the time.
Use a PIC processor or similar. One part, got the memory and everything
you need except the light driver.
mike

 

[Joerg]

Hi Durall,

Why don't you use CD4000 series flip flops? Those draw just microamps
when not DC-loaded at the outputs so you may be able to leave them
connected to the battery all the time.

Fresh air helps. But I don't have that luxury now. Too many wildfires,
soot and ash everywhere and a huge shroud of gray.

Regards, Joerg

 

[Tony Williams]

I understand that a flip-flop will toggle between states when a
button is pressed. I'd like to know though, will it hold state
with NO power?

I have an led that I'd like to power with 4 'D' batteries. The
first time that I push the button, I'd like the LED to stay on.
The second time that I push the button the LED will go off. The
Flip-flop circuit will lose power too. The next time I push the
button, I'd like the LED to flash, say 3 times/second. 4th Push,
off again. Circuit loses power again. Goto first push.

CMOS that is static (not clocking) will probably take
less current than the internal leakage of the battery,
but look out for the ambush of any pullup/down resistor
that might be active when the device is OFF.

For example, don't disable that 3Hz oscillator into a
state where a timing resistor is drawing current.

 

[Tim Shoppa]

I understand that a flip-flop will toggle between states when a button
is pressed. I'd like to know though, will it hold state with NO power?

I have an led that I'd like to power with 4 'D' batteries. The first
time that I push the button, I'd like the LED to stay on. The second
time that I push the button the LED will go off. The Flip-flop circuit
will lose power too. The next time I push the button, I'd like the LED
to flash, say 3 times/second. 4th Push, off again. Circuit loses power
again. Goto first push.

Should I just step away from the soldering iron and get some fresh
air?

Known as a "latching relay": bistable. You can get 2 toggle-action latching
relays and cascade them like a ripple counter, or you can get 4 more
conventional latching relays and use the contacts to steer the next
pulse like a 4-stage ring counter. Or use two relays as a Johnson/
twisted-ring counter.

Also there are "rotary step relays" that advance one position round a
circle on each pulse. All you really need is a one 4-position rotary
step relay.

tim.

 

[Spajky]

Gotta have some memory somewhere. Mechanical switch memory,
semiconductor memory, past-life memory...

... remember ferrite bread non volatile memory? ...

looks like "they" are gonna revive it again in chips:
naturally done with nanotubes printed onto semiconductor wafer in
modern thin manufacturing process ...

 

[Ken Smith]

I understand that a flip-flop will toggle between states when a button
is pressed. I'd like to know though, will it hold state with NO power?

This sounds like a one bit FRAM is needed. I wonder if a X7R ceramic cap
actually remembers forever. If so maybe we could come up with a one bit
FRAM using parts that are easy to get.

We could also use a "solion" device. Some of them are bidirectional.

 

[Frank Bemelman]

This sounds like a one bit FRAM is needed. I wonder if a X7R ceramic cap
actually remembers forever. If so maybe we could come up with a one bit
FRAM using parts that are easy to get.

We could also use a "solion" device. Some of them are bidirectional.

The OP want 4 states, two of them 'off', and one flashing. While it can be
done with standard logic, using a cap to power the flipflop, I'd go for
a LP2985 regulator with on/off pin, and a 12F629 pic. 6 parts, a cap
for decoupling, a resistor, the regulator an the pic can do the debounce,
has eeprom to store the states, and to do the flashing, and two diodes
to route the switch to the input and regulator. Oh, well maybe an
extra resistor. 8 parts.

 

[colin]

I understand that a flip-flop will toggle between states when a button
is pressed. I'd like to know though, will it hold state with NO power?

I have an led that I'd like to power with 4 'D' batteries. The first
time that I push the button, I'd like the LED to stay on. The second
time that I push the button the LED will go off. The Flip-flop circuit
will lose power too. The next time I push the button, I'd like the LED
to flash, say 3 times/second. 4th Push, off again. Circuit loses power
again. Goto first push.

Should I just step away from the soldering iron and get some fresh
air?

you could go for the mechanical aproach, each push of the button pushes a
shaft round 90' with a pawl/ratchet mechanism.
cams on each end of the shaft operate contacts as needed. you can get push
buton switches wich have the same mechanism but only 2 positions.

Colin =^.^=

 

[David Lesher]

....

Known as a "latching relay": bistable. You can get 2 toggle-action latching
relays

I have [somewhere....] some Korean Wall era magnetic latching relays.
You hit them with + - voltage and it would toggle one way...and
stay. Give it - + and get the other state.

(I somewhere read this was done with bias magnets but I'm not sure; they
are in typical Mil-Spec hermetically sealed cans.)

 

[Robert Baer]

...

Known as a "latching relay": bistable. You can get 2 toggle-action latching
relays

I have [somewhere....] some Korean Wall era magnetic latching relays.
You hit them with + - voltage and it would toggle one way...and
stay. Give it - + and get the other state.

(I somewhere read this was done with bias magnets but I'm not sure; they
are in typical Mil-Spec hermetically sealed cans.)

--
A host is a host from coast to [email protected]
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Aie-yup! Magnets are used for the latching.

 

[R. Steve Walz]

I understand that a flip-flop will toggle between states when a button
is pressed. I'd like to know though, will it hold state with NO power? ...

Known as a "latching relay": bistable. You can get 2 toggle-action latching
relays

I have [somewhere....] some Korean Wall era magnetic latching relays.
You hit them with + - voltage and it would toggle one way...and
stay. Give it - + and get the other state.

(I somewhere read this was done with bias magnets but I'm not sure; they
are in typical Mil-Spec hermetically sealed cans.)

--
A host is a host from coast to [email protected]
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Aie-yup! Magnets are used for the latching.

--------------------------------
I've seen a latching relay that used a latching mechanism like a push-on
push-off switch. One coil, and it latches and unlatches with a
sufficient pulse length. I've also seen one that latches back and forth
with two opposing coils and each untraps the pawl holding it to the
other and pulls it to latch its own way.

-Steve

 

[Tim Shoppa]

...

Known as a "latching relay": bistable. You can get 2 toggle-action latching
relays

I have [somewhere....] some Korean Wall era magnetic latching relays.
You hit them with + - voltage and it would toggle one way...and
stay. Give it - + and get the other state.

(I somewhere read this was done with bias magnets but I'm not sure; they
are in typical Mil-Spec hermetically sealed cans.)

Related, there are "polar relays" which are driven by bipolar voltages.
By definition they had no return spring so would tend to remember their last
state but usually it wasn't guaranteed that they'd continue to make contact
after current was removed. Maybe adding small "hold" magnets to these
turns it into what you have there.

Polar relays were very useful in high-speed long-line telegraphy. Unlike
spring-return relays which have different make and break timings, the
polar relay is pretty much symmetrical. And the bipolar drive gets around
the rise/fall times of very long copper pairs.

The original RS-232 voltage levels are an outgrowth of polar relay
voltage levels. It makes me cringe when I see all the gadgets which assume
that a positive voltage slightly above ground is a marking signal.

Tim.

 

[David Lesher]

Related, there are "polar relays" which are driven by bipolar voltages.
By definition they had no return spring so would tend to remember their last
state but usually it wasn't guaranteed that they'd continue to make contact
after current was removed. Maybe adding small "hold" magnets to these
turns it into what you have there.

Nod, that goes back a few years.

A very similar delicate dual-coil balanced relay was the heart of
A-D converters I used to have to maintain. The 4-20 mA went through
one coil; a balancing current through the other. Closing one direction
would make a 4-decade 10 relay/decade counter "count up" -- the
other would count down. Each relay switched in a resistor value
proportional to the relay "value". {Thinking about it, maybe inversely;
as you want I to go up thus R must go down...}

Another deck of each relay constructed the digital output from
the closed ones.

When the process value changed, the dual-coil relay would go hard
over, and the Units, then Tens, Hundreds and Thousand decades would
tumble {"braatt, thawk, braatt....} until it overshot, stopped and
hunted back...

Decades later, I remain amazed it worked at all, much less so well for
almost 20 years.