I have a project where I want to measure current and or voltage in household appliances. Can you tell me what sensors or other componants I would need to measure this. I want to hook these up to a Raspberry Pi 3 Thanks for your help Peter
Sounds like an interesting project in work! You do not want to be interfacing with house hold appliances by direct means, as 240VAC is incredibly dangerous if you are not qualified.
With that said, AC current is Alternating Current - with a few turns of wire around the appliance power lead you can measure the current of the device very easily. Well, easily enough. The AC will induce a varying voltage onto the wire which is proportional to current. Given voltage will always be constant, you can work out all the power formulas based on current.
If you used something like this, you could calibrate the low-tech sensor with known values.
Or bypass all of that and use a dedicate non-invasive current sensor such as this.
Whatever option you go with, you’ll need an ADC device because there isn’t on onboard the Pi.
Thanks for the reply. I was defiantly going down the non intrusive path for safety and simplicity. The CT sensor you referenced is for loads up to 30 Amps so that would be in the right range for a domestic fridge? Also with this CT clip can it be placed around the appliance power lead when the lead has the earth, neutral and active all to together. I ask this as some of the background research I have done talk about CT clips only working when placed around the active. Or are there different types of CT.
Thanks again for the info this is great help
The earth etc can reduce the strength of the sensed voltage, however, it’s all relative and part of the calibration process. Once the offset is understood, you can convert measured voltage into current and perform any power related maths.
Standard home appliances are less than 10Amp.
Thanks mate great help