Toggle or JK flip-flop which retains state with power loss.

Toggle or D flip-flop which retains state with power loss.

I am basically looking for info on a circuit that would behave exactly like a unidirectional one-coil latching relay. A signal turns on the relay. Power can be maintained or lost and the relay stays in the "on" state. An identical signal turns off the relay. Unfortunately, such a relay seems to cost over $100 and seems rare. I think this might also be called a T flip-flop scenario.

I am trying to come up with a battery powered system that utilizes a 1.2VDC signal from a timer to activate a motor. A second signal from the timer would reverse the motor maybe 10 hours later. I don't want to be wasting battery power in that time, so I was going to have the timer go on for one minute then of again, then on and off again later to reverse the motor. I was hoping I could have nothing powered in the meantime (like the relay option) to conserve battery.

If I was to have the timer just go on to start the motor in one direction, then stay on for 10 hours, then go off to reverse it, I think this would be a D flip-flop. But then I would have to power the flip-flop electronics for the 10 hours duration, right?

I have an electronics background I would call "a little past beginner." Could you please advise as to possible routes to take on this project?

Thanks.

With any F/F you will need to maintain power to maintain the state. The good news is that a CMOS F/F takes almost zero power when not in the process of switching. So you could design a circuit that while in between run times the battery only supplies power to the F/F and minimum other circuitry. I would need a bit more information to provide more help. What is the motor drive circuit look like? Directly driven off the 1.2VDC or is there some kind of drive relay and other power? How do you reverse the motor? What would the battery voltage run, the motor, drive circuit only or ?

But from what you have stated, a battery powered circuit could be designed where the motor direction memory takes practically zero power.

If you end up powering only part of the circuit remember there are diodes on the inputs to most IC that connect to both supplies, power and ground which can cause a sneak path for current drain or even power up the powered down circuit.

Ray

I hope this schematic answers some questions. I've been thinking about this all day and wonder if this would work?



I'm not sure if transistors can be used like this, but let me explain the operation I'm trying to get here:

The timer's clock is ticking away. When the "on" signal goes off, +1.2V is given on the signal pin. This opens the NPN transistor, which allows 6 volts to first latch the relay into position then also provide power for the motor. (I would need a relay with a coil voltage of 6V and a 6V motor.) The motor is now turning clockwise. When the "off" time is reached +0V is given on the timer signal pin. The NPN transistor turns off, and the PNP transistor turns on. This allows 6V to flow into the second coil, latching the relay in the opposite direction, and allows 6V to flow through the second pole of the relay to move the motor counterclockwise.

Do you think this setup will work? I'm unsure about the transistor part. If the transistors will not function properly, can you suggest a different component that will turn "on" with first 1.2V and then 0V signals?

Thanks for the help.