Adafruit QT Py ESP32 + Neokey 1×4

This is a little “note to self” post, similar to the ones I did on hex math, mason jar sizes, and microswitch pinouts. It’s probably not of general interest unless you arrive here by way of Google, Duck Duck Go, or Kagi.

The Adafruit QT Py ESP32 is a little (and I mean tiny) board with an ESP32 microcontroller. This thing, not much larger than my thumbnail has all the bells and whistles, including Wifi, Bluetooth, and a STEMMA QT connector (which supplies I2C and 3.3VDC).

The Adafruit Neokey 1×4 QT I2C board is a little board with a dedicated microcontroller that queries four mechanical keyswitches, powers four backlight LEDs and communicates over I2C. It also has a STEMMA QT connector.

Just plug one into the other and run the File > Examples > Adafruit seesaw > Neokey_1x4 > basic example, right? It turns out that doesn’t work.

It turns out that this line:

Adafruit_NeoKey_1x4 neokey;  // Create the NeoKey object

Needs to be altered to this:

Adafruit_NeoKey_1x4 neokey(0x30, &Wire1);  // Create the NeoKey object

That’s all. That’s the blog post. A mental note for Future Me. Also, and this may just be my USB-C cable, I had to crank down the upload speed from 921600 to 115200.

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Brian Enigma

Brian Enigma is a Portlander, manipulator of atoms & bits, minor-league blogger, and all-around great guy. He typically writes about the interesting “maker” projects he's working on, but sometimes veers off into puzzles, software, games, local news, and current events.

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