ESP32-PoE and MOD-MPU6050 Communication Fault

[trulyBent]

We bought a number of ESP32-PoE boards (and a few ESP32-PoE-ISO boards) as well as a number of your MOD-MPU6050s; the type with the ribbon cable and UEXT connector. You'd think that making them work would be as simple as plugging the two together, however none of the boards are unable to read any of the MOD-MPU6050s. I checked schematics to make sure there were pullup resistors on the SCL and SDA lines, which there appear to be.

We are able to wire up other non-UEXT type MPU6050s, from other manufacturers, to the boards and they work fine. We're thinking that we may have received a bad batch of MOD-MPU6050s.

We are using simple I2C scanner software, which tests addresses from 0 to 127, but it's not reporting anything for the MOD-MPU6050.

By the way, who fabricates an extension board without a power LED? Just a pet peeve of mine.

[LubOlimex]

We just tested it, the combo of ESP32-PoE-ISO and MOD-MPU6050 works fine by just UEXT connection. Probably it is something in your software. I recommend you to test with Arduino IDE:

First install the ESP32 for Arduino JSON via the board manager. As explained here:

https://github.com/espressif/arduino-esp32/blob/master/docs/arduino-ide/boards_manager.md


Then install the Adafruit MPU6050 library (can be found in the Library Manager (Tools -> Library manager), filter by "mpu6050" and install the Adafruit library version 2.0.2). After installation make sure that Olimex ESP32-PoE (or PoE-ISO if you used such board) is selected from the board selector and load the demo example from the Adafruit MPU6050 library.

By the way, who fabricates an extension board without a power LED? Just a pet peeve of mine.

We do. We also have some boards like ESP32-PoE-ISO that would keep all LEDs unpowered when powering the board via battery. This is because a lot of our boards are used in power critical setups and battery-only setups where current consumption matters and often a LED consumes more than the main chip.

[trulyBent]

@lubolimex
Thanks for the response. I followed your instructions and downloaded the "basic_readings" example into an Olimex ESP32-PoE. However, the sensor still cannot be seen. Following is a printout from the serial monitor:

rst:0x1 (POWERON_RESET),boot:0x1b (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0018,len:4
load:0x3fff001c,len:1044
load:0x40078000,len:8896
load:0x40080400,len:5816
entry 0x400806ac
Adafruit MPU6050 test!
Failed to find MPU6050 chip


It's beginning to look as though the MPU6050 has been compromised.

[LubOlimex]

Can you send me picture of you hardware setup when testing - ESP32-PoE-ISO + cable + MOD-MPU6050?

Send me an e-mail at support@olimex.com with the picture and link to this forum thread so we don't go over all the support questions again; I will also need your purchase information so I can track if there is a note here about a specific batch or something.