Testing new sensors using the expansion connector

Due to the IDG/ISZ-500 gyros EOL problem we are removing the  IDG/ISZ-500/BMA145 and going for the MPU-6050 instead. We where pretty certain the gyro part of the MPU-6050 would work but not so sure about the accelerometer.

To minimize the risk we wanted to try it out with our design before pushing the order button. We looked around for small IMUs with this chip and found that the FreeIMU uses the sensors that we are interested in testing. So we bought one and attached to the Crazyflie using the expansion connector. Here’s a image of what it looks like:

Since we now free up some space by replacing three sensor ICs with one we added a HMC5883L magnetometer and MS5611 pressure sensor which are the most common IMU sensors right now. If they will be mounted or not in the final version depends on cost and possible performance increase. If we don’t mount them there is always the possibility to do this yourself. Actually, as of this writing, we just made a virgin flight using the MPU-6050 data from the FreeIMU with good results.

7 comments on “Testing new sensors using the expansion connector

  • Using the freeIMU would be realy cool, because it can also be used for other multicopters (e.g. its supported by multiwii) -but isn’t this guy alone about 80$ ? And does a pressure sensor makes sense for an indor-multicopter like this – I mean whats the estimated resolution in hight?

  • We only use the FreeIMU to test the sensors in our application. The sensors will be part of the Crazyflie PCB.

    Yes, you might be right about the pressure sensor, it might not be usable indoor but according to spec its accuracy is within 10cm. The pressure indoor is probably not that stable so we will have to see about that. It doesn’t hurt to have the footprint there though.

  • Hey, cool project and thanks for trying FreeIMU.. let me know if I can be of help in your project. Since FreeIMU is completely Open Hardware and designed in KiCAD, I’m sure the schematics and footprints will be very useful for you. As you may already know, designs are up here while footprints are in my KiCAD library.
    Good luck with your project.


    • Hello Fabio. We like your work very much and thanks for reaching out a helping hand. We will let you know if we have any questions but as for now everything workes just fine ;-)

  • I’m looking for some pairs of counter rotating props that are the same size for a scratch built micro quadrotor that I’ve built. I know you guys got the originals as spares from the SilverLit X-twin. But I can’t seem to find a reasonable source for them in the US. Where are you getting your props from?

    This is an awesome project you have going. Keep up the work.

    • Getting the props is a hassle. We have mainly got them from harvested SilverLit planes and e-bay but after a lot of searching we have recently found a Chinese factory that we can buy similar props from, but in very large quantities. So that doesn’t help you. However we plan to sell spare props through Seeedstudio as soon as everything is available but until then I’m afraid we can’t help you :-(

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