I was trying to calculate the amount of water flow in my project; however, it is pretty much impossible to find an NPT water flow meter. NPS to NPT adapters exist, but they are ridiculously pricey.
Ideally, I would like to provide an emergency shut-off as well if the pump has been running for too long, so this seemed like a good fit for an Arduino.
My assumption is that the current would increase if the pump is running, but I'm not sure how to measure that via Arduino. I assume I could provide a switch (probably a MOSFET?) that would switch power off if I send a signal to it. Thanks.
I don't see a problem of adding a water flow sensor. These pumps normally connect to 8 mm hose (at least, mine do). Haven't tried this kind of pump with water flow sensor, but other pumps with 8 mm hose connect just fine to a flow sensor. No issues there. There are flow sensors that give you the actual flow, and flow switches that are simple on/off switches based on flow or no flow.
You really do need a flow meter.
Measuring the time that power is applied is useful for some values, but pretty loose for volume pumped...
Lack of prime, and other issues aren’t addressed... including whether or not the pump motor is actually running.
Even a simple flow switch would be an option.
EDIT: @wvm - ‘snap’ !
If you put the flow sensor on the suction side then you can just use low cost barbed fittings and flexible PVC tubing. If you find difficulty in finding adaptors that are the exact size then you can improvise by putting the tube ends in hot water for a few minutes to make them flexible and stretchy. Once cooled down to room temperature the PVC remembers the new shape.
If you are using the 12v version of the pump as in the Amazon picture then the 30 amp version of the ACS712 current sensor is a robust and safe option. For switching, pick a mosfet that can handle at least 30 amps and always use a protection diode across the motor.
The pump is an on-demand pump, so it switches on when it detects a differential in pressure on the outlet side (i.e. opening up a faucet).
The flow sensors I find are all NPS (straight threads), and NPT is the standard thread (tapered) in the US. I've called numerous companies to see if they carry NPS to NPT adapters, and well I can't seem to find any. Here's a flow sensor for example:
The flow switch seems like a great idea. Could someone post an example of a flow switch I could use for Arduino? Preferably something cheap, but effective. Thank you so much.
The MOSFET I was considering using was
Do you think those are good choices? The pump will be powered by either a 12V power supply or a 12V 7aH lead acid battery on solar.
Also, is the MOSFET a good choice to switch power to the pump? Or should I consider a different component?