Error with Example6 Sensor Tutorial

I’m using a ESP32 with a notecarrier A.
Arduino IDE 1.8.19
Both ESP and note carrier hooked up with USB. (to power Notecarrier)
SCL on ESP to SCL on notecarrier.
The only alteration of the sketch is to add my ID to #define PRODUCT_UID
Here is the error message I get in the serial monitor:

[ERROR] i2c: timeout {io}
[ERROR] error encountered during I2C transmit hook execution

I hate to admit this but I had this working at one point!!

Any help will be appreciated!!

Do you mind sharing a picture of your setup?

i2c: timeout {io} would typically indicate an issue with the wiring. Either there is bad signal between the Notecard and ESP32 or there is a power problem.

Both may become more obvious with a photograph.


Picture attached. The carrier and ESP are stuck to an unused PCB with thick double stick tape. They are isolated from the PCB.

This is from the event body:

    "text": "boot (brown-out & hard reset [16292])",
    "voltage": 4.8710938

Try to plug a jumper from one header to another marked GND on each device. They need a common reference to ground so they can interpret signals cleanly; I don’t think ground from the USB plugs will cut it.

As far as the brown out is concerned, the modem can generate a 2A spike. Most laptop USB connectors are only rated for 500mA. If you have a LiPo handy, plug it into the Notecarrier, and that will clean up the brown outs.


I hooked up ground jumper and have hooked up a lipo (measures 3.9V) and solar panel. I get the same arduino message:

[ERROR] i2c: timeout {io}
[ERROR] error encountered during I2C transmit hook execution

and this in the event log

{“text”:“boot (brown-out & hard reset [16292])”,“voltage”:3.8710938}

even with the lipo attached, since it’s a small one and not the highest voltage— I charged up a 18650 and have it attached now. here’s the event message:

“text”: “boot (brown-out & hard reset [16292])”,
“voltage”: 4.234375

Same serial monitor info

Problem solved. It was a bad ESP

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