MPU6050 - GY521 issues

I am using Jeff Rowberg's code for reading my MPU6050 and have had no problem reading values and using the associated Processing file that he provided. My problem is that I'm able to do this on one SainSmart manufactured mpu6050 sensor that I ordered a while ago and not on the two new Kootek sensors.

I'm following all of the instructions closely and am puzzled as to why I'm so stumped by these similar sensors. I believe my soldering is fine and I'm getting the power to the sensor just fine, however, the serial monitor indicates, "connection failed" at startup. I have tried adding resistors, playing with the I2C address, etc. Other codes that I have run (Odis Harkins, Arduino playground - mpu6050 sample code) confirm that there is a connection error.

What might I be missing?

My connections are the following: 5V --> VCC SCL --> A5 SDA --> A4 GND --> GND (ADO --> GND) tried with and without INT --> D2

Again, I can get all of this source code to work perfectly with my other mpu, but not the two new Kootek GY521. Any help will be greatly appreciated.

Thank you for your time.

Run the i2c_scanner : http://playground.arduino.cc/Main/I2cScanner Can you give a link to your product ? Where did you buy it ? Maybe the module is bad.

Thank you very much for the reply. I did run the I2C scanner and like I expected the two Kootek mpu sensors are not identified. Sure enough, I plug in the SainSmart manufactured mpu and it is identified by the Scanner. I might suppose I'll try resoldering the pins, but I'm doubtful (hopeful) this will work.

For reference:

SainSmart manufactured MPU6050 (working just fine)

www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=sainsmart+mpu

Kootek manufactured version (the problem sensors)

http://www.amazon.com/Kootek-MPU-6050-MPU6050-sensors-Accelerometer/dp/B008BOPN40/ref=sr_1_1?ie=UTF8&qid=1462058169&sr=8-1&keywords=kootek+mpu

Thanks, again for the response. Naturally, I'm on a major crunch for time to get these sensors to work as I'm using them for a project so any and all feedback is greatly appreciated.

Call off the chase.... magically works now. I'll let you know what the source of my problem was if I ever discover the true cause. I resoldered the pins, and restarted arduino and they are working. I am skeptical that the soldering (not to sound confident) was the culprit as I doubt that my soldering was consistently poor (looked fine to me) enough to have connection issues yet still provide power to the sensors. Anyways, thank you Koepel for the response and to anyone else that pondered my dilemma.

Are you using a Arduino Uno ? Then the voltage levels for SDA and SCL of 3.3V are not enough for the Arduino Uno. You need a level shifter for SDA, SCL and INT.

Are the pullup resistors for SDA and SCL on the modules 2k2 ? (label "222"). That is low. If you have two of those modules on the I2C bus, the total combined pullup might be too low.

Someone reported that there are such modules with the wrong capacitor. One of the capacitors at the pins of the MPU-6050 should be 22nF and one should be 100nF, but 22nF was used for both. The module will work, but the data will be very noisy.

Thank you for following up on my post. Those resistors on the module are in fact "222." I'll keep that in mind as I debug some of the issues I am having. I had gotten the devices to work, but I did not monitor the output values for yaw, pitch, and roll (I am assuming that the accelerations are garbage as well) closely before putting the project down for the time being. Now that I am back at it, I first observe rapid oscillations for the yaw angle, while the others are relatively static at random values. After the oscillations stop, there are no reliable values reported regarding orientation. For example, I can rotate the device on each axis 180 degrees and the device may only recognize ~80 degrees for a single axis and the others give significantly smaller readings. Kind of puzzling.

Fortunately, I have an alternative sensor to get the results from my experiment, but I do need to figure out what is going on here as I intend on using these gyros in the future. Any input from those reading would be greatly appreciated. I'll post whatever success or failures I have while I work on this. Thanks, again Koepel for the help.

Koepel: Are you using a Arduino Uno ? Then the voltage levels for SDA and SCL of 3.3V are not enough for the Arduino Uno. You need a level shifter for SDA, SCL and INT.

Are the pullup resistors for SDA and SCL on the modules 2k2 ? (label "222"). That is low. If you have two of those modules on the I2C bus, the total combined pullup might be too low.

Someone reported that there are such modules with the wrong capacitor. One of the capacitors at the pins of the MPU-6050 should be 22nF and one should be 100nF, but 22nF was used for both. The module will work, but the data will be very noisy.

I have one project of camera servo gimbal. I use MPU6050 with Arduino UNO. There's no any problem. And it's work fine running.

My project link VDO : https://www.youtube.com/watch?v=TD9pkeKE_Q0

Great project Isaranu! Thank you for sharing. Do you have any issues with values drifting over time? Just curious as this is something I've yet to test on the MPU6050.