ESP8266 Community Forum

- Fri Dec 11, 2015 2:05 pm #36233 I'm working on a project in wich I want the following:
RFID reader
temperature probe(DS1820)
current sensor ( https://store.arduino.cc/product/E000019 )
4 outputs (1 relay, 3 LEDs)
4 inputs (button)
Is it possible to do this with a ESP8266?

I was planning on using a raspberryPi, but somebody told me I should do it with the ESP8266.

If I were to do it with the ESP8266, what would I need? 8266 + Arduino? Or only 8266?

- Fri Dec 11, 2015 10:45 pm #36253 Assuming the RFID reader is an UART device, it should be possible with an ESP-12 or similar without an additional microcontroller (you would max out the gpio pins, though).
However keep in mind that the ESP's ADC has a max. input voltage of 1V.
And concerning the current transformer: you should choose one with a current rating larger than the max. expected current, but as close as possible to the expected value. A 100A CT is most likely overkill and will have a very low output (and thus result in inacurate reading), unless you really want to measure currents in the 20-100A range.

- Sat Dec 12, 2015 3:18 am #36260 I'd use an external I2C or SPI ADC chip rather than using the built-in for that current sensor as the built in ADC has too many limitations (IMHO) to be useful since you have to disable WiFi whilst taking a reading. The rest should all be fine though.
Cheers,
Ben

- Sat Dec 12, 2015 5:35 am #36263 For that kind of current transformer you need a better ADC than the ESP8266 internal one. Are you sure you need 100A capabilities out there?

MCP3421 ADC is a good choice, decent price, upto 18bit, example here: MCP3421 I2C Driver example and here Analog Extension Board for ESP8266

OR you can use a isolated current chip, like the ACS712 one, example here: ESP8266 - ACS712 Current Sensor Board and Part 2 : Software example for ACS712 Sensor Board

ESP8266 MPDMv4 AC MAINS Dimmer Home: http://esp8266-projects.com/2016/04/mpdmv4-mains-dimmerswitch-html/
Available on Tindie: https://www.tindie.com/products/nEXT_EVO1/universal-ac-mains-dimmer-mpdmv41/