Hi.
I need to sense when a water pump is pumping at regular intervals.
The pump is self-contained, and although you can set the pump pressure switch to what you want, there is no access to the switch itself.
Therefore, I was planning to simply pass the phase wire(complete with insulation for safety) through a toroid core a few times, and put quite a few turns on the other side of the toroid using thin enameled copper wire, which would then be connected to a half-wave rectifier and decoupling cap. The idea being that when the pump starts up, a voltage will be induced in the enameled wire by the current being drawn through the 230v phase on the other side of the toroid core, producing a voltage that the Picaxe can then detect - it would not need to be that much voltage - a few volts would probably be enough for the Picaxe to detect it. There might be more required then that(an amplifying transistor arrangement perhaps) if there is not enough induced voltage from this idea, but that is the general concept.
A timer routine can be setup to time how long the motor is on for, but the next bit is the tricky part:
- Detect whenever the motor is routinely switching on and off, and when there is a pattern, switch off the juice to the motor stopping it until manually reset.
The problem with that, is that the duty-cycle for ON-OFF pump condition can be anything - 5 minutes or 50 seconds - you name it.
I know how to deal with the first event, but not sure how to approach having the PIC detect a pattern of regular on/off cycles.
This is all being done, as there is a master water tank of some 20,000 liters, and a buffer "Pressure tank" which is kept at a water pressure of about 8lbs/sq. inch. The pump sucks water from the main tank, and pushes it into the pressure tank until the pressure in the pressure-tank is 8lbs or so, at which point, the pump switches off until the pressure in the pressure tank drops, and when that happens, the pump switches on again, and builds up the pressure again, before switching off.
Depending on how quickly the water is being taken from the pressure tank, the pump can be switching on and off quite a bit, or hardly at all - it all depends on water demand.
REMEMBER - You cannot access the pressure switch - it is built into the pump assembly's water output valve.
Any ideas on how to detect a regular on/off pattern?
I need to sense when a water pump is pumping at regular intervals.
The pump is self-contained, and although you can set the pump pressure switch to what you want, there is no access to the switch itself.
Therefore, I was planning to simply pass the phase wire(complete with insulation for safety) through a toroid core a few times, and put quite a few turns on the other side of the toroid using thin enameled copper wire, which would then be connected to a half-wave rectifier and decoupling cap. The idea being that when the pump starts up, a voltage will be induced in the enameled wire by the current being drawn through the 230v phase on the other side of the toroid core, producing a voltage that the Picaxe can then detect - it would not need to be that much voltage - a few volts would probably be enough for the Picaxe to detect it. There might be more required then that(an amplifying transistor arrangement perhaps) if there is not enough induced voltage from this idea, but that is the general concept.
A timer routine can be setup to time how long the motor is on for, but the next bit is the tricky part:
- Detect whenever the motor is routinely switching on and off, and when there is a pattern, switch off the juice to the motor stopping it until manually reset.
The problem with that, is that the duty-cycle for ON-OFF pump condition can be anything - 5 minutes or 50 seconds - you name it.
I know how to deal with the first event, but not sure how to approach having the PIC detect a pattern of regular on/off cycles.
This is all being done, as there is a master water tank of some 20,000 liters, and a buffer "Pressure tank" which is kept at a water pressure of about 8lbs/sq. inch. The pump sucks water from the main tank, and pushes it into the pressure tank until the pressure in the pressure-tank is 8lbs or so, at which point, the pump switches off until the pressure in the pressure tank drops, and when that happens, the pump switches on again, and builds up the pressure again, before switching off.
Depending on how quickly the water is being taken from the pressure tank, the pump can be switching on and off quite a bit, or hardly at all - it all depends on water demand.
REMEMBER - You cannot access the pressure switch - it is built into the pump assembly's water output valve.
Any ideas on how to detect a regular on/off pattern?