Actions
Forum Thread Details
  • State Suggested Answer
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 507 subscribers
  • Views 520 views
  • Users 0 members are here
Related

Circuit to control a latching relay by toggling the power supply

phil.harlow

My end goal is to control a garden hose valve (https://smile.amazon.com/dp/B003LY4I2I/) with a power supply plugged into a cheap wireless switch. (https://smile.amazon.com/gp/product/B00DQELHBS)

The valve uses a 24v latching impulse relay.

I would like to use passive electronics. I'd like to not use arduino, or anything requiring an additional power supply. Ideally no battery as well.

In essence, I would like the circuit to provide a 24v pulse to open the valve when it first receives power, and then stores enough power in a capacitor to provide a momentary reverse polarity pulse again to close the valve when the circuit loses power.

I'm sure this problem has been solved a million times before, and I know this is a loaded question, but I'm still learning terminology, so any help pointing me in the right direction would be much appreciated!

Thanks!

  • 0

    What you ask is almost impossible - the capacitor will always discharge after time and since it must power the passive detection circuit it will discharge quite fast.

     

    If you are willing to keep power on all the time the valve is on (so the power can keep the reverse spike generating circuit topped up) it might be possible to come up with a passive ciruit that would turn the valve off when the power is removed.  If you are using the wireless switches you have mains power anyway - why not just replace the valve with a non latching one - it will be easier.

     

    MK

  • 0

    It would be helpful if you could diagram what you described. You talk about  needing to store energy in a capacitor but then you also mention when it looses power. Why does it need to store power if it has power to loose?  If you have power at the valve you could make a circuit the pulses the relay with power that alternates polarity with each push of the remote button. Also perhaps you can clarify terminology. Are we dealing with a latching relay that controls a water solenoid valve or is it some sort of latching water solenoid?

    John

  • 0

    Another alternative is to use one channel to turn on and a second channel to turn off...

    If you only have one channel, you might try building a flip flop with 2 relays such each activation toggles the flip flop to direct the pulse to different latching relay coils. This might need continuous power but these relays could be low power.

  • 0

    Thanks for the help guys. I certainly did not describe the problem very well, but I've given up completely and just bought a valve that is NC, and opens with 24v, so I can just turn the power supply on and off to open the valve, solving my issue.

     

    Thanks for the help!