ESP8266 Community Forum

Hello everyone,

I hope someone can help me as I am out of ideas. I have a NodeMCU board which I want to connect to an Air Quality sensor (CCS811) from sparkfun. I connected the sensor's SDA and SCL to pins D2 and D1 respectively, but when I compile the "Basic Readings" sample code provided with the CCS811 library (https://learn.sparkfun.com/tutorials/cc ... 1492205268) I get an error after uploading the code:

Z+�I$��9r��CCS811 Basic Example
.begin() returned with an error.

Soft WDT reset

ctx: cont
sp: 3ffef2b0 end: 3ffef490 offset: 01b0

>>>stack>>>
3ffef460: 3fffdad0 00000000 3ffee440 402020ac
3ffef470: feefeffe feefeffe 3ffee45c 40202cb8
3ffef480: feefeffe feefeffe 3ffee470 40100114
<<<stack<<<

Can someone please help me out? I tried running the code in an Arduino Nano and it ran perfectly, so my only guess is that the code is not reading the SDA, SCL signals from the D1/D2 pins, but I don't know where I could change this.

Any help is appreciated.

Same problem here, let me know if you find a solution. I use my own sketch (no library) and I'm able to read from sensor's register basic informations about sensor (STATUS,HW_ID,HW_VERSION...) but when I try to switch to app mode by



ESP8266 (I use Wemos D1 Pro) goes to soft reset (the same issue as you have)...
I use combo sensor CJMCU-8118 with HDC1080 humidity/thermometer. The second sensor on the board works fine without issues. Also no issues with both sensors on Arduino Uno.

Are you sure you have connected the wake wire properly? (i connected it to the ground on my nodemcu). its stated to not be required but worth a try.

Petre:how did you get the temp and humidity from this combo board please?

I also have a strange problem. after a while (random interval between 1 minute to 1 hour) i start getting the same error, soft wdt reset. failed to start the sensor. i need to either reset the board or disconnect and reconnect the power to bring it back to life. have you guys faced this issue?

BTW jorgeg922 try ada fruit library instead of the spartfun.

https://learn.adafruit.com/adafruit-ccs ... r?view=all

also can you let me know how you got temp and humidity working?i have asked Petr also.