Pb IMU Brick 2.0 with Python 3.6

[JPannetier]

Hello ,

 

I'm using Python 3.6.

 

I can run the example to emunerate my device.

When I'm using example_simple.py from IMU brick 2.0.

I have an error message from  imu.get_quaternion()

 

in get_quaternion

    return GetQuaternion(*self.ipcon.send_request(self, BrickIMU.FUNCTION_GET_QUATERNION, (), '', 'f f f f'))

 

  File "C:\Users\JPannetier\Anaconda3\lib\site-packages\tinkerforge\ip_connection.py", line 1194, in send_request

    return unpack_payload(response[8:], form_ret)

 

  File "C:\Users\JPannetier\Anaconda3\lib\site-packages\tinkerforge\ip_connection.py", line 251, in unpack_payload

    x = struct.unpack(f, data[:length])

 

error: unpack requires a buffer of 4 bytes

 

Thank you

Best regard

[photron]

This isn't a Problem with Python 3.6. The Problem ist that you're using the IMU Brick (1.0) example with an IMU Brick 2.0. Try this example:

 

https://www.tinkerforge.com/en/doc/Software/Bricks/IMUV2_Brick_Python.html#simple

[JPannetier]

Hi Photron,

 

Exactly.

I have a IMU Brick 2.0.

And I have this error when i'm using your example of IMU Brick 2.0....

 

Best regard

[borg]

But it says "BrickIMU.FUNCTION_GET_QUATERNION" in your pasted error message. It should be "BrickIMUV2". Are you sure you are not using the IMU 1.0 example?

[JPannetier]

I'm using a Brick IMU 2.0 with its example :

https://www.tinkerforge.com/en/doc/Software/Bricks/IMUV2_Brick_Python.html#simple

 

When I opened the source of Brick IMU 2.0, i can notice :

Into communication.c :

 

void get_quaternion(const ComType com, const GetQuaternion *data) {

GetQuaternionReturn gqr;

 

gqr.header        = data->header;

gqr.header.length = sizeof(GetQuaternionReturn);

gqr.x            = sensor_data.qua_x;

gqr.y            = sensor_data.qua_y;

gqr.z            = sensor_data.qua_z;

gqr.w            = sensor_data.qua_w;

 

send_blocking_with_timeout(&gqr, sizeof(GetQuaternionReturn), com);

}

 

And into communication.h

 

typedef struct {

MessageHeader header;

int16_t w;

int16_t x;

int16_t y;

int16_t z;

} __attribute__((__packed__)) GetQuaternionReturn;

 

 

 

 

[borg]

The error message above comes from the IMU Brick 1.0 bindings. You can see it from the names and also because of the "f f f f", since the 1.0 IMU returned floats while the new one returns ints.

 

Please download the example again from here https://www.tinkerforge.com/en/doc/Software/Bricks/IMUV2_Brick_Python.html#simple and try it again.

[JPannetier]

Super,

 

It's working now.

Sorry for my mistake.

Thank you very much for your support.

 

Best regard Jérôme