I am trying to address an I2C device on my Huzzah Feather (Adafruit) ESP8266, but the I2C scanner tool does not detect anything. All is sufficiently powered and quadruple checked the wiring.

Is there something I am missing for this board in regards to I2C connections?

I've had no issue on an Arduino, which uses the 2 pins on the Analog rail for I2C...

The Huzzah has no Analogue But the one pin, regardless, Huzzah Feather has different (still pin 4 & 5 tho) I2C, and not via A0 A1 like on the Uno.

Do I need to dig deep and change some pin configurations for the Huzzah?

Thought I would ask before wasting more time on trial and error experiments.

Update Note:

I failed to mention there is a Feather Neopixel board (4x32) hard soldered to the board. Which I suspect is not the culprit as this issue also persists on same board without the neopixel shield attached.


The soldering job was good, but discovered a faulty wire. This allowed the I2C scanner to detect the i2C controller (LCD2004) at the address of 0x3F...

I checked with a I2c LCD library example, and I don't get any characters to come up... This is the same with both Huzzah Feather boards, one with Neopixel shield and the other is bare.

  • use Wire.begin(SDA_PIN, SCL_PIN);
    – Juraj
    Commented Aug 8, 2019 at 5:45
  • @Juraj The Wire library has an overloaded ::begin() that does that for you for the default pins SDA and SCL.
    – Majenko
    Commented Aug 8, 2019 at 9:48
  • @Majenko, the begin() without parameters uses pins defined in variant. but, yes, I checked it now and the Huzzah Feather has 4 and 5 defined
    – Juraj
    Commented Aug 8, 2019 at 11:02
  • I tried this Wire.begin(4,5); and issue persists.
    – mrSidX
    Commented Aug 8, 2019 at 17:58

1 Answer 1


This particular issue was due to a faulty wire on the I2C bus. I replaced the wire and I was able to scan and get an address to the I2C LCD controller.

I still cannot get text to the LCD. I will start a new question for that.


Upon scrapping my I2C_LCD_DISPLAY library, I downloaded one that was linked in a ESP32/8266 tutorial for the LCD, and finally got it working.

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