ESP8266 Community Forum

- Wed May 20, 2015 9:42 am #17963 Hi @Bygambituk, Yes, the ESP12 haves an ADC pin with 0-1v range.

I've now a domotic system using Souliss and based on Arduino Boards, but now Souliss Support ESP as native board, so I want to change every nodes of the network with ESP boards. Other option is read the CT with an Arduino and send the data to the ESP, but if I can I want to integrate the library directly over an ESP and load it via Arduino-ESP-IDE from this forum.

The Main problem is how to convert the scheme before to a 3.3v power source and a limit of 1V on Analog In, take care I use a SCT-013-000 (0-100A Output 0-50mA (1:2000)) I need to investigate what resistors are needed, just before I can start with the library integration.

Regards

- Wed May 20, 2015 10:51 am #17968 Ok, so i am looking at the values, and i believe it should be 22Ω resistor, not 220Ω.. i will look at the other values later.

- Wed May 20, 2015 11:13 am #17971 with R1 = 10kΩ and R2 3k9 Ω resistors which will give a voltage range of 0 - 0.926V according to my calculations.

I have last week tried to integrate the emonLib into a sketch for MQTT to also allow me to send data to an openHAB system i have running. But it failed, but i have not been able to take the time to look at modifying the library. I am currently using arduino ide 1.6.4

I hope we can get this to work.

- Wed May 20, 2015 11:34 am #17974 Yes, on this web* recommends to use a 18ohm for 3.3v, 30ohm for 5v to use all the CT Range but I used a 220ohm burden resistor to reduce the range of the CT from 100A to 30-40A (I dont remember where I found this and how calculated this, I do some time ago and I don't find the post) I have this configuration working on Arduino and calibrated with a 2000w heater and the messure is ok.

*Here you've a post with the explanation: http://openenergymonitor.org/emon/node/58

Regards