Hello,
I'm trying to work my way around an automated irrigation system I'd like to build, I bought a bunch of VHM-014 (12 v) circuits so theoretically I should have everything I need for it.
Except that I'm struggling to find the right valves to actually open/shut the water flow.
Initially I bought some 12v solenoid valves, but quickly realised that with water pressure they won't open just on battery power (8 AA), and I tried with a 2A 12v transformer, it wouldn't open either (it does open when no/little pressure is applied).
I disassembled an old Gardena T14 which works with a 9v battery and figured that this device uses a latching 9v valve, that opens with an impulse in one direction and closes with an inverted impulse (i.e. switching + a -).
My VHM-014 are simpler than that and simply open a relay when they figure we need watering and close it when they figure they watered enough.
So I thought I need to explore converting this VHM-014 output so that when the relay closes and my circuit is energised (12v) it needs to send out a single pulse to the latching valve with a given + and - orientation.
Then when the circuit loses power it needs to send another pulse with + and - inverted, maybe using a capacitor?
technically I could use the same 12v source to power the circuit so to have power to send the closing pulse. Ideally I'd like this system to use the least possible current, so that I won't have to replace batteries too often.
something like this:
I need to fill the gap between D1 and D2 (through the solenoid) and equally through D3 and D4 (also through the solenoid)
U4 would be activated by the VHM-014 when watering is needed
can anyone help me out here?
thanks,
UPDATE: I've just learned of the H bridge, with relays, that can invert polarity from a power source to a consumer (ex. a latching valve) building one of these I would just need some kind of system that when current is applied only a pulse is sent, then stop.
with two relays and two of these systems I could complete my setup.
any ideas about how to build such a device to just send a pulse?
I'm trying to work my way around an automated irrigation system I'd like to build, I bought a bunch of VHM-014 (12 v) circuits so theoretically I should have everything I need for it.
Except that I'm struggling to find the right valves to actually open/shut the water flow.
Initially I bought some 12v solenoid valves, but quickly realised that with water pressure they won't open just on battery power (8 AA), and I tried with a 2A 12v transformer, it wouldn't open either (it does open when no/little pressure is applied).
I disassembled an old Gardena T14 which works with a 9v battery and figured that this device uses a latching 9v valve, that opens with an impulse in one direction and closes with an inverted impulse (i.e. switching + a -).
My VHM-014 are simpler than that and simply open a relay when they figure we need watering and close it when they figure they watered enough.
So I thought I need to explore converting this VHM-014 output so that when the relay closes and my circuit is energised (12v) it needs to send out a single pulse to the latching valve with a given + and - orientation.
Then when the circuit loses power it needs to send another pulse with + and - inverted, maybe using a capacitor?
technically I could use the same 12v source to power the circuit so to have power to send the closing pulse. Ideally I'd like this system to use the least possible current, so that I won't have to replace batteries too often.
something like this:
I need to fill the gap between D1 and D2 (through the solenoid) and equally through D3 and D4 (also through the solenoid)
U4 would be activated by the VHM-014 when watering is needed
can anyone help me out here?
thanks,
UPDATE: I've just learned of the H bridge, with relays, that can invert polarity from a power source to a consumer (ex. a latching valve) building one of these I would just need some kind of system that when current is applied only a pulse is sent, then stop.
with two relays and two of these systems I could complete my setup.
any ideas about how to build such a device to just send a pulse?