Mains voltage current sensor?

[maghac]

Any advice on sensing current in mains voltage (240V) circuits?

What I'm trying to do is to monitor the dishwasher and washing machines, so I can sense when they're done and alert someone to go empty them.

[sundberg84]

@maghac - I have just ordered som parts im going to play around with.
I bought the 30A current sensor but there are also som clamps so you dont have to make any cuts into wires:
https://www.mysensors.org/store/power

I think im going to build a portable Swedish plug standard machine, something looking like a relay but measures current.
https://ae01.alicdn.com/kf/HTB1WHv.MpXXXXcwXFXXq6xXFXXXA/AC-230V-Digital-16A-LCD-Electric-1W-3680W-Power-Energy-Meter-Voltage-Wattage-font-b-Current.jpg

[HenryWhite]

@maghac said in Mains voltage current sensor?:

so I can sense when they're done and alert someone to go empty them.

If you just want to do that, you could also use a vibration sensor to determine whether the dryer/ washing machine has finished or not.

[maghac]

@HenryWhite That would work for the washing machine, but not for the dishwasher I guess as it doesn't move a lot

[wallyllama]

Www.openenergymonitor.org has a lot of info on current, voltage, and power monitoring. It isnt mysensors specific, but it is detailed and can likely be made to work.

[gohan]

Sonoff pow?

[zboblamont]

@maghac Why measure current? It will vary with the program in use, and so will water consumption. Both devices have controllers, both will signal the end of a cycle and go standby, usually triggering a bleeper, these are usually low volt DC. Tap into that?
You must have a distant machine not to hear it, I can hear the washing machine bleep through a wall, the dishwasher is usually quiet until she finishes, then gets noisy again

[gohan]

@zboblamont because it's easier to attach a sensor to the power plug instead of hacking the machine's controller . For what is worth, I think that a normal countdown timer will be enough since washing cycles have always the same length.

[maghac]

Exactly, I don't want to modify the appliances in any way

If I monitor the current drawn by the appliance I can detect both when it starts and when it finishes. With a countdown timer I need to start it myself and if I forget to start it I will not get a reminder when it's done.

[maghac]

The sonoff pow looks interesting actually. 10 USD is a really good price.

[gohan]

you can make a dash button that when pressed sets a timer on the controller. With sonoff pow you get energy metering and also a relay tu turn on and off your appliance