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EduBall Simulink Model

A project log for Smart Juggling Balls

Smart Juggling Balls for Juggling and Education

ArkadiArkadi 06/29/2015 at 10:160 Comments

A few updates,

I have recently added a Matlab Simulink model to the GitHub including additional code, the model is also available on Matlab file exchange: Simulink Model.

The model is designed to check the feasibility of the project, in terms of what Physical phenomena i can actually demonstrate with the current hardware setup. The setup is quite simple, The juggling ball is used to measure the Acc/Gyro values and transmit it to a "dongle" (NRF_Receive) which is connected to the computer via USB. The Simulink model reads the values through a COM Port and performs some simple data manipulations. The update rate of the data is set to 100 Hz.

The simulink model is used to demonstrate Acc/Gyro Raw values, Acc/Gyro Scaled and biased values. Normal Acceleration and Rotation Rate. angle calculation based on Gyro integration and Acc gravity vector calculation. and the final is complementary filter demonstration with comparison between the different approaches.

See image as to how it all looks:

Conclusions:

From the Acceleration reading it is very clear to distinguish Free fall and average g such as 1g when the ball is still. It is possible to see the high g`s when the ball is hit, but not at enough sample rate to perform any calculations based on the data such as energy conservation when the ball is thrown and caught at the same height)

The centrifugal forces are also very clear to demonstrate and to actually compare them to the gyro rotation rate, (as long as the gyro isn`t saturated (at 2000 deg/sec).

finally it seems that the hardware is good enough for most demonstrations, (still there is a lot of work ahead to actually build a class curriculum and run a pilot).


The current stage of the project:

- Find a big company which is interested in supporting the project

- Test better hardware setup, to get higher sample rate (1 KHz), and with wider range of the accelerometer (200g).

- Find someone interested in education to help with the curriculum

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