IMU, Encoders
Where Am I?

IMU - Inertial Measurement Unit

- The XRP controller board includes a LSM6DSO 6-Dof IMU [datasheet]
  "The LSM6DSO is a 6-axis IMU (inertial measurement unit) system-in-package featuring a 3-axis digital accelerometer and a 3-axis digital gyroscope"
- The device is an example of a MEMS:
  "MEMS (micro-electromechanical systems) is the technology of microscopic devices incorporating both electronic and moving parts."
- The XRP firmware uses the IMU and the motor encoders to implement the "Drive Train ... Straight, Turn, Arcade" functions
- Review: The Encoders

Experiment

Let's look at the values of the IMU and Encoders to see how they change when we move the XRP.
Download and run this imu_test.blocks program. (Shown here --->)
Run the program and observe the sensor values as you manually move the XRP is various dimensions.
(turn left and right, tilt up/down/left/right, flip upside down)
Pick up the XRP a couple of inches from the table and gently drop it.
Can you associate all the motions with each of the sensor values?
(Hint: Look at the x,y,z graphic printed on the XRP controller board.)
Look at the generated Python code for this program.

Write some code!

- Write a program that uses one or more of the sensor values some way.
  You can use Blocks or Micropython.
  Ideas:
  - Blink the LED and change blink rate in response to one of the sensor values.
    (You'll need to do some math, or if/then/else code to map the sensor value to the number of blinks.)
  - Use the IMU to keep the servo arm horizontal as the XRP is tilted up and down.
    Which works better -- the accelerometer or the gyroscope?
  - Detect when the XRP drives into a wall using the accelerometer.
  - In Python, use the OLED display to graphically indicate the left/right tilt to the XRP.
    (Consider drawing a line and moving it left and right as the XRP is tilted.)
- Your ideas?

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