Small CT coil and Raspberry Pi


#1

Hello, I was wondering if anyone has found a CT Coil that would work with Raspberry Pi and would act as a digital input and let you know when something it on?


#2

@adam or @kreggly might know of something


#3

Hi @adbrig4,

So I am assuming you are talking something like an AC lamp right?

There are lots of ways to do this, and the coil size will be based on what kind of current you are using.

https://www.dfrobot.com/product-1486.html

This split core guy can be clipped over a cable and puts out a proportional output. If you want a digital, then you will need a comparator board with a pot on it to set the trip point, or add an SPI based analog input board.

Code to get this working on an Arduino is included in the link.

Cheers,

Craig


#4

Lamps, small appliances etc. do you have any suggestions on a comparator board for use with a RaspberryPi?

kreggly Leader
October 19 |

Hi @adbrig4,

So I am assuming you are talking something like an AC lamp right?

There are lots of ways to do this, and the coil size will be based on what kind of current you are using.

https://www.dfrobot.com/product-1486.html

This split core guy can be clipped over a cable and puts out a proportional output. If you want a digital, then you will need a comparator board with a pot on it to set the trip point, or add an SPI based analog input board.

Code to get this working on an Arduino is included in the link.

Cheers,

Craig

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#5

@adbrig4,

I’d go the other way, and grab one of the supported ADC extensions from the Cayenne dashboard and build a trigger off the analog value.

I like the ADS1115 myself as you can get it as a little board and just hook up the signals with jumpers.

It also has programmable gains to really get fine resolution and as an added bonus, comes with a programmable comparator as a secondary output.

You can get them way cheaper from China, but Adafruit are good people.

Cheers,

Craig