esp-01 doesn't connect to GY-87 (MPU6050)

[ith]

Hi All,

I hope I'm posting to the right section of the forum, if not please point me to the right place.
I'm a bit new to ESP9266 and so far this forum has been very helpful, so I wish to thank all of you!

We're trying to connect an ESP-01 to a GY-87 board (with an MPU6050 unit), but no matter what we tried, the ESP doesn't recognize the MPU6050. Running the i2c scanner code doesn't find any i2c device, reading the WHO_AM_I register returns 255 and trying to read raw sensor data shows only values of -1.

Connecting the GY-87 to an Arduino Uno works perfectly: i2c scanner recognizes it on 0x68 as it should, and sensor data is streaming fine. We didn't need any additional resistors to connect to the Arduino Uno, just the simple 3.3, GND, SDA and SCL connections.

The ESP-01 seems to be working fine as well - we're able to setup an access point, send and receive UDP, blink GPIO 0 and 1, etc.

So we have good reasons to believe that both boards are functional, and the problem is either with the connections or with the code.

Our connections:

ESP-01 GY-87
-------- -------
VCC 3.3V
GND GND
GPIO-0 SCL
GPIO-1 SDA

(We also tried to switch between SDA and SCL, but to no avail)

We tried to connect some resistors (10K) after the SDA and SDL - didn't help.
Also tried to connect INTA to GND - didn't help.

The codes we're executing are mostly example codes we found in Arduino Playground, in this forum and in some blogs - nothing special. We're using the libraries Wire.h and MPU6050.h, everything's working with Arduino, but not with the ESP-01.

What are we missing? We're almost desperate

Any help, any idea you guys might have, will be very much appreciated,

Thanks,

Ith & Tal - See more at: http://www.esp8266.com/viewtopic.php?f= ... dU6Ap.dpuf

[Domosapiens]

Just to make sure ...
Looking at this diagram:

and this picture:



VCC_IN is for 5V
If you use 3.3V you must use the 3.3V connection point (that's after the voltage regulator)

Just my 2 cents

[talb]

Hey, I'm tal - Ith's Partner.
We use 3.3v everywhere on the circuit - the same goes for the GY-87.
The VCC pin on The ESP's output supposed to be around 3.3 because we power it through FTDI set to 3.3 output Or 3.6 Lithium ion battery - however using the 3.3v pin on the GY-87 is supposed to reduce the voltage to the desired one... I guess Voltage is not causing the troubles here.

There are some more "funny" issues occur when trying to connect the SCL and SDA to GPIO 0 adn GPIO 2, there is a specific variation that causes the Blue LED (Indicating Data Transfer and Network activity) to blink irregularly, moreover the network connection seems to freeze. I think that the data received from the SDA pin is causing some interference with the WiFi and some other capabilities of the ESP.

When using the Arduino UNO there were no such issues - We connected the 3.3v pin from the UNO to the (same) 3.3v GY 87 and It worked just great.
So I guess the cause is not the Voltage rather it might be the way the ESP 8266 uses I2C connectivity via it's GPIO pins.

Maybe we should use some resistors somehow on SDA or SCL connections?
I tried some options but none had any success...

Has somebody here tried to connect any 9-dof sensors (with gyro, magnometer and accelerometer) to this ESP and it worked?

Thanks

Tal & Ith

[LisaM]

Hey, I'm tal - Ith's Partner.
We use 3.3v everywhere on the circuit - the same goes for the GY-87.
The VCC pin on The ESP's output supposed to be around 3.3 because we power it through FTDI set to 3.3 output Or 3.6 Lithium ion battery - however using the 3.3v pin on the GY-87 is supposed to reduce the voltage to the desired one... I guess Voltage is not causing the troubles here.

There are some more "funny" issues occur when trying to connect the SCL and SDA to GPIO 0 adn GPIO 2, there is a specific variation that causes the Blue LED (Indicating Data Transfer and Network activity) to blink irregularly, moreover the network connection seems to freeze. I think that the data received from the SDA pin is causing some interference with the WiFi and some other capabilities of the ESP.

When using the Arduino UNO there were no such issues - We connected the 3.3v pin from the UNO to the (same) 3.3v GY 87 and It worked just great.
So I guess the cause is not the Voltage rather it might be the way the ESP 8266 uses I2C connectivity via it's GPIO pins.

Maybe we should use some resistors somehow on SDA or SCL connections?
I tried some options but none had any success...

Has somebody here tried to connect any 9-dof sensors (with gyro, magnometer and accelerometer) to this ESP and it worked?

Thanks

Tal & Ith

Isn't gpio1 and 3 being used for tx/rx? On my espeasy2, gpio 1/3 are grayed out for the i2c interface.
Gpio 0/2 should be available for i2c. Did you also try it with an esp-12 and different gpio's for i2c?

[Shardan]

Isn't gpio1 and 3 being used for tx/rx? On my espeasy2, gpio 1/3 are grayed out for the i2c interface.
Gpio 0/2 should be available for i2c. Did you also try it with an esp-12 and different gpio's for i2c?

Yep, definitely.
Please use GPIO0 and GPIO2 for the I2C.

GPIO1/3 are used for serial communication.
In general it is possible to use GPIO1/3 for other purposes by switching off serial in the ESPEasy setup.
I nevertheless would avoid using them for I2C.

If you monitor your ESP on serial you will see some erratic letters and numbers on bootup.
The ESP sends some bootup messages there with another serial speed, that's why you see letter garbage.
If using these GPIOs for I2C you may send some data to the connected sensors at boot they can't understand.
I'm not sure if the following initialization process gets rid of this data and init all I2C devices correctly.

Regards
Shardan

[ith]

Hi, bumping this one last time..
We're close to desperation and are considering to drop the ESP8266 altogether and switch to Arduino Nano (which is less suitable to our needs, but at least it works!)

Hasn't anyone succeeded in connecting ESP-01 and MPU6050 via I2C ?
Isn't it supposed to be super-simple?
Please help if you have ANY thoughts.

ThanX
ith

[grovkillen]

Have you tried another ESP? In general gpio 4 and 5 are used for I2C.

https://www.letscontrolit.com/wiki/inde ... figuration

Is a WeMos D1 mini to big for your application?

[ith]

Thanks for responding, grovkillen!

Our project needs to be very small, that's why I chose to use the ESP-01, which only has GPIO 0 and 2.
Anyhow, as I understand it, it shouldn't really matter because I can use Wire.begin(0,2) to set i2c communication via GPIO 0 and 2.

What am I doing wrong??

[grovkillen]

Sorry for bugging you but have you tried a WeMos just to make sure that it's not the board that is the problem?

[ith]

grovkillen, you're not bugging me at all - like I said ANY information is helpful

And indeed, I wasn't aware of WeMos so thanks so much about that tip! The D1 series seems to fit our needs so we'll test it soon.

So far I've been using a generic ESP-01, tried three units with zero success - what are the odds I'll get 3 broken ones in a row?
On Arduino Uno everything works right away so I'm guessing it's not the code or the wiring.

Thanks again, I'll post an update after I've tested WeMos.

Any other thoughts from anybody?

ith