eimu-serial 1.1.1

Python serial interface for the Easy IMU (EIMU)

Easy IMU (EIMU) Python Library

Python serial interface for the Easy IMU (EIMU).

you can use it in your microcomputer robotics project (e.g Raspberry Pi, PC, etc.)

Install

• you'll need to pip install the pyserial library

    pip3 install eimu-serial   //linux or mac
    pip install eimu-serial  //windows
  

Uninstall

• you'll need to pip install the pyserial library

    pip3 uninstall eimu-serial   //linux or mac
    pip uninstall eimu-serial  //windows
  

How to Use the Library

• Ensure you have the EIMU MODULE interfaced with your PC or microcomputer

• Ensure you have the Easy IMU Module is already calibrated and setup with the eimu_setup_application

• check the serial port the driver is connected to:

  ls /dev/ttyA*
  

  you should see /dev/ttyACM0 or /dev/ttyACM1 and so on

• use the serial port in your code

• A simple way to get started is simply to try out the example code below

Basic Library functions and usage

• connect to the EIMU module

  imu = EIMUSerialClient()

  imu.connect("port_name or port_path")

• clear imu, filter, e.t.c data buffer on the EIMU module

  imu.clearDataBuffer() # returns bool -> success

• set imu reference frame -> NWU (0), ENU (1), NED (2)

  imu.setWorldFrameId(frame_id)

• get imu reference frame -> NWU (0), ENU (1), NED (2)

  imu.getWorldFrameId() # returns tuple -> (success, frame_id): bool, int

• adjust filter gain

  imu.setFilterGain(gain)

• read filter gain

  imu.getFilterGain() # returns tuple -> (success, gain): bool, float

• read all IMU data (orientation - RPY, linear acceleration, angular velocity)

  imu.readImuData() # returns tuple -> (success, r, p, y, ax, ay, az, gx, gy, gz): bool, float, float, float, float, float, float, float, float, float

• read Oreintation - Quaterninos

  imu.readQuat() # returns tuple -> (success, qw, qx, qy, qz): bool, float, float, float, float

• read Oreintation - RPY

  imu.readRPY() # returns tuple -> (success, r, p, y): bool, float, float, float

• read Linear Acceleration

  imu.readLinearAcc() # returns tuple -> (success, ax, ay, az): bool, float, float, float

• read Gyro (Angular velocity)

  imu.readGyro() # returns tuple -> (success, gx, gy, gz): bool, float, float, float

• while these function above help communicate with the already configure EPMC module, more examples of advanced funtions usage for parameter tuning can be found in the eimu_setup_application source code

example code

from eimu_serial import EIMUSerialClient
import time
from math import pi

toRad = 2 * pi / 360
toDeg = 1 / toRad

imu = EIMUSerialClient()

def main():
  # 50Hz comm setup
  serial_port = '/dev/ttyACM0'
  serial_baudrate = 115200
  serial_timeout = 0.018 #value < 0.02 (for 50Hz comm)

  imu.connect(serial_port, serial_baudrate, serial_timeout)

  for i in range(4):
    time.sleep(1.0)
    print(i+1, " sec")

  success = imu.clearDataBuffer()

  # change the reference frame to ENU frame (0 - NWU,  1 - ENU,  2 - NED)
  imu.setWorldFrameId(1)

  # check the reference frame the eimu is working in (0 - NWU,  1 - ENU,  2 - NED)
  success, ref_frame_id = imu.getWorldFrameId()
  if success:
    if ref_frame_id == 0:
      print("Reference Frame is North-West-Up (NWU)")
    elif ref_frame_id == 1:
      print("Reference Frame is East-North-Up (ENU)")
    elif ref_frame_id == 2:
      print("Reference Frame is North-East-Down (NED)")
  else:
    print("Could not get world frame ID")

  prevTime = time.time()
  sampleTime = 0.02 #( 50Hz comm)

  while True:
    if time.time() - prevTime > sampleTime:
      success, r, p, y, ax, ay, az, gx, gy, gz = imu.readImuData()

      if success:
        print(f"r: {round(r*toDeg,2)}\tp: {round(p*toDeg,2)}\ty: {round(y*toDeg,2)}")
        print(f"ax: {ax}\tay: {ay}\taz: {az}")
        print(f"gx: {gx}\tgy: {gy}\tgz: {gz}")
        print()
      else:
        print("Error reading IMU data")
      prevTime = time.time()

if __name__ == "__main__":
  main()