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FIRST PROOF OF CONCEPT

A project log for IMcoders

IMU-based encoders. IMcoders provides odometry data to robots with a minimal integration effort, easing prototyping on almost any system.

pablo-leyvaPablo Leyva 05/21/2018 at 20:390 Comments

The Firstborn

To test the viability of the idea a first prototype was developed and tested (with success!). The aesthetic was no priority and the soldering skills at the moment unavailable or nonexistent.

After some prototyping in the protoboard and making sure that the tool chains were correctly installed, devices reachable and git repositories clean and commited a more reliable development platform was needed, and so the hardware V0.1 was borned.

With this device the integration with RTIMULib was tested and support for the MPU9250 device through SPI added.

We would like to specially thank mrbichel for doing the heavy lifting with his project RTIMULib, wich provides a great framework to interface with IMUs. It really help us a lot to just focus on the application and rely on his framework to send the data to the computer.

Side Note: At the very beginning, the development of the sensor started with the GY-85 IMU board but was quickly changed in favor of the MPU9250. In our forked version of the RTIMULib there is now support for the GY-85 too (even though it is not used anymore).

Going Wireless

The basic functionality of the device was already working and the computer was able to receive data, it was time to go wireless. The bluetooth module was configured and a LiPo Battery included.

The size of the PCB was reduced and a new 3D printed cased printed. Now the sensor fits easily in your hand and it is now ready for “real world” experiments.

ROS Integration

As our goal is to use the sensors in robotic applications, the integration with the ROS framework was always in the roadmap. A first small and basic ROS node reading the IMU packet was developed and tested.

Now that everything's kind of working we need more sensors! It is time to design our own PCB and make them smaller! (or at least thinners...)

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