IMU not detected - GY-91 sensor module (BMP-280 & MPU9250)

[Tom60]

Well this is probably of no use to you but let me try. I have a gy-91 and it works fine.

Pi4 4GB, OPv3 64bit, all latest updates.

I connect the gy-91 (powering the 3.3V pin from 3.3V on the pi)

I run some tests to check that the pi can see both BMP280 and the IMU and that works fine

i2cdetect -y 1 shows the correct addresses - 68 (MPU), 76 (BMP280)

Start Pypilot (v3.2.13), and it shows Detected IMU-925x

I select IMU only

Approve the access request and give read/write permissions

In Pypilot I seem to need to click IMU only again but after that the data appears in Signal K

I can calibrate the device in Pypilot without issue.

I know there have been issues with some gy-91s but my experience is different.

I'd be happy to send one of you my gy-91 to try if you like.

Note I am connecting directly to the pi, not via a PICAN hat.

Hi  Baltika_no_9,

Thanks for the reply and that is very useful information.

I also have a  Pi4 4GB, OPv3 64bit, all latest updates

However I had the GY-91 connected to the GPIO 5V pin and at the other end the wire was connect to the VIN pin on the module.  I've now changed it to your pin settings.  

Running  i2cdetect -y   I only get the 76 for the BMP820 

PyPilot still shows 

Detected IMU: none
Detected Hardware: No PyPilot HAT detected
No UART0 port detected

I too am directly connecting to the Pi GPIO 

I'm starting to wonder if the GY-91 is faulty.  Thank you for the offer to send a module to test.   I'm in Perth, West Australia and I suspect you are far away :-)  I might order a second module to confirm my suspicions.

[baltika_no_9]

I think trying another one is your only realistic option isn't it or you could spent a lot of time getting nowhere. Problems with alleged gy-91s can be found referenced in lots of places on the web including in these forums. It seems there were very many fake ones produced but with the MPU6050 and not the MPU9250.

I also have a Waveshare device that works well with Openplotter, it's from a reliable manufacturer and quality is good. https://www.waveshare.com/10-dof-imu-sensor-c.htm

It uses the MPU9250; they do have a later version but that is based on the ICM20948 and I am not sure that is OK with OP.

Good luck

[Tom60]

Thanks for the link.  I've already ordered another GY-91.  (From a different seller!)  If that doesn't work then I'll try buying one from your link.  

I still have time as our grandson doesn't intend to sail into the SW Pacific until mid next year.

[Tom60]

New GY-91 module received today. Another DUD not recognized by Openplotter :-(

I have ordered a 3rd from the above link (USA) Different looking module which I hope will work!

[baltika_no_9]

Tom

That's astonishing. You say it isn't recognised by Openplotter (Pypilot showing no IMU detected?) but what about the OS? Are you saying that the i2detect command only shows one address still?

[Tom60]

This 3rd module is worse than the first two. The BMP820 worked for an hour and then stopped. The IMU was identified by the 12C and I had barometric pressure and temperature. But not the IMU. The 3rd (latest) module purchased isn't detected by either I2C or Pypilot. I've given up on Chinese retailers.

[Tom60]

Well I have the pressure and temperature back. I suspect I had the SCA and SCL pins reversed. (my error.. old eyes).

Running i2cdetect -y 1 from the Terminal shows addresses 68 and 76

I suspect 68 is the IMU as 76 is the BMP820.

However PyPilot 3.2.13 shows 'Detected IMU: none' with the 'Enable IMU Only' option

[baltika_no_9]

Well I have the pressure and temperature back.  I suspect I had the SCA and SCL pins reversed. (my error.. old eyes).

Running i2cdetect -y 1 from the Terminal shows addresses 68 and 76

I suspect 68 is the IMU as 76 is the BMP820.

However PyPilot 3.2.13 shows 'Detected IMU: none' with the 'Enable IMU Only' option

Excellent! You are correct in terms of the addresses.

Good luck

[rszemeti]

I have some similar but different issues ... 3 IMU tried, PyPilot can find them, but the heading data produced is useless.

I cannot find any good information. the boatimu service is running ... I have installed PyPilot ... I cannot find any information if I am supposed to have both of them installed. When I click the help links, the documentation just says "coming soon" I cannot find a good explanation of how it is supposed to wok ... I uninstalled PyPilot and the boatimu service is running, so maybe it does not need PyPilot to function for heading data ... I don't know.

From what I can tell, the plane of the magnetic data is not aligned with gravity ... when I make a circle in the boat (around the Z axis, or in the XY plane) it appears in the calibration screen as a circle in the YZ plane (around the X axis) ...

[Tom60]

I have some similar but different issues ... 3 IMU tried, PyPilot can find them, but the heading data produced is useless.

I cannot find any good information.  the boatimu service is running ... I have installed PyPilot ... I cannot find any information if I am supposed to have both of them installed.  When I click the help links, the documentation just says "coming soon"  I cannot find a good explanation of how it is supposed to wok ... I uninstalled PyPilot and the boatimu service is running, so maybe it does not need PyPilot to function for heading data ... I don't know.

From what I can tell, the plane of the magnetic data is not aligned with gravity ... when I make a circle in the boat (around the Z axis,  or in the XY plane) it appears in the calibration screen as a circle in the YZ plane (around the X axis) ...


You have progressed further than me so I can't provide any advice from my own experience to date.  I believe the documentation for Openplotter V3 is still being written which is why you see "coming soon".  I think the PyPilot module in Openplotter has to be installed for the IMU to be configured (calibrated).  Did you calibrate the IMU after it had been detected and installed?