What IMU?

[vandiver]

Hello everyone,

My name is Borja, first post here, thanks a lot for accepting me.

I am starting my Pi + OP project and would like to install an IMU to start with, I got a not working board (MPU92/65) from Amazon, not recognized neither by I2C nor by Pypilot...both with Openplotter and BBNOS, is there any version of IMU easy to find in the typical channels? I am getting crazy to get for example an ICM20948 (would that even work?) as an alternative any HAT that has this integrated and serves for additional purposes that might interesting (in my case no NMEA 2k, or no need for Autopilot....)

Any recommendations at this point are most welcome, guess that the question is very much repeated in the forum, my apologies if that has been already been answered.

Thanks and greetings from Spain!

Best regards,

[Jean-Marc Douroux]

Hello,

The IMU cannot work without Pypilot or at least the Pypilot boatimu script to determine roll, pitch and magnetic heading. You must also have set the RPI for the I2C port to be functional.

The integrated circuit ICM20948 operates at 1.7V while the RPI operates at 3.3V. There are ICM20948 modules with the ICM20948 that only work at 1.7V while others work between 2 and 6V thanks to a converter and interfaces in the module. Only those operating between 2 and 6V are RPI and Arduino compatible.

[vandiver]

Hello,

The IMU cannot work without Pypilot or at least the Pypilot boatimu script to determine roll, pitch and magnetic heading. You must also have set the RPI for the I2C port to be functional.

The integrated circuit ICM20948 operates at 1.7V while the RPI operates at 3.3V. There are ICM20948 modules with the ICM20948 that only work at 1.7V while others work between 2 and 6V thanks to a converter and interfaces in the module. Only those operating between 2 and 6V are RPI and Arduino compatible.

Thanks for the hint, yes, I am counting with I2C Interface and Pypilot within OP3. The question was referring to the specific reference/model or IMU sensor that will work best and that is feasible to find. I found some docs in Github about IMU sensors compatible with the available libraries, from the list I was able to find in a reasonable price this model which I have ordered - Pololu MinIMU-9 v5 - hope it works well, I will return the previous mpu version that was not recognized by Pypilot….

[vandiver]

So now I bought the Pololu MinIMU-9 v5 from the list of compatible IMUs after failing to connect a MPU 92/65 IMU I bought through Amazon, but it doesn't neither work, it seems not be recognized by I2C neither by Pypilot....what I am doing wrong?

[Sailoog]

Use only ICM-20948 (recommended), MPU-9250 or MPU-9255.

[seandepagnier]

Can you find the sensor via i2c-detect?

[vandiver]

Can you find the sensor via i2c-detect?

No, matrix completely empty

I am quite a newby in Electronics (despite being a Mechanical Engineer), hope I connected everything ok, checked couple of times...    

[AndyV]

Use only ICM-20948 (recommended), MPU-9250 or MPU-9255.

Does this look right to you? Long delivery time so wanted to confirm before I get it and find it's not the right one for pypilot. Board just seems a little too simplistic, but I'm no electrical engineer.

Or, if you have a link for where I can purchase one let me know, cheers!

[seandepagnier]

that board usually runs at 1v8 where the pi is 3v3.

You need level translators which can be just 2 mosfets and a few resistors.

A lot of icm20948 boards have the level translators on them, that board does not.

[Jean-Marc Douroux]

Use only ICM-20948 (recommended), MPU-9250 or MPU-9255.

Does this look right to you? Long delivery time so wanted to confirm before I get it and find it's not the right one for pypilot. Board just seems a little too simplistic, but I'm no electrical engineer.

Or, if you have a link for where I can purchase one let me know, cheers!

Hello
ICM20948 is actually an integrated circuit that only operates at 1.7V. Some ICM20948 modules are equipped with a DC converter to allow the module to operate at 3.3V and 5V. Other modules with very few components added to the ICM20948, as in the photo of your ad, can only work with 1.7V power supply as well as an adaptation of the I2C signals which are at 3.3V with the PI. The ideal is to purchase an ICM20948 module operating between 2 and 6V. It is then directly compatible with RPI and Arduino.

Here is an ebay ad with a module that can operate from 1.8V to 5V :
NEW BMP388 ICM20948 10DOF Acceleration Gyroscope Compass 9-axis Sensor Module