Create3 sensing colors

[fmorshed52]

How are you connecting to your Create 3?

Wi-Fi (ROS 2)

Computer(s) Model(s) and Operating System(s)

Windows XP

Which version of ROS 2 is installed on your computer?

Galactic

Which firmware version is installed on your robot?

Irrelevant to my question

Which RMW is your robot running?

I don't know

Does your robot have an assigned namespace? If so, please share.

No response

Is the robot connected to a network? If so, what is the network type?

Bluetooth

Are there multiple Create 3 robots connected to your network?

None

Is multicast enabled?

No

What is the Adapter Board's USB/BLE Toggle currently switched to?

Bluetooth (default)

Describe your question.

Does anyone have an example of Create3 code that can do the equivalent of Root's
line_following_events_3_areas.py example
where it has an event defined as below under root_robots Examples tab in the IDE?:
@event(robot.when_color_scanned, [ColorID.SKIP, ColorID.SKIP, ColorID.GREEN])

I believe it would need to use the cliff_sensor event or get_ir_proximity. Not sure.

Any ideas?

[fmorshed52]

I was on the wrong track. It is not get_ir_proximity. It is ir_intensity for what I need to do, which is to follow a line. I had brought this up here: #373. It was implemented. My problem is that I don't know how to get the values for the ir_intensity using python in the web playground.

intensity = (await robot.get_ir_intensity()) 

does not work. I need to get the values in the cliff_intensity topic Example here: https://iroboteducation.github.io/create3_docs/api/hazards/#the-cliff_intensity-topic

Any ideas?

[fmorshed52]

In the modified example I described above, when I pick up the Create3 and put it down to invoke the cliff sensors, I get this error: exception=AttributeError("'Create3' object has no attribute 'get_cliff_intensity'"). What this tells me is that the Create3 robot does not have this API defined for it.

Unless I am mistaking here somewhere, and future release of the API is not going to define it, I am out of luck using the cliff intensity data in Create3 to follow a line from Python code.

Please confirm.

[fmorshed52]

Could you add get_cliff_intensity to irobot_edu_sdk/create3.py please?

[shamlian]

The Python SDK on the Create 3 robot can only implement functionality exposed in the BLE protocol here. I do not believe the cliff intensities are exposed, so this data is not available. An iRobot employee would have to update the robot software itself for that to be possible. That said, from looking at the data available via ROS 2, I'm not sure how useful the data out of the sensor would actually be. Have you looked at your line using the sensor available in the ROS 2 cliff_intensity topic?

[fmorshed52]

shamlian, I have, described here. But I don't know how to call an API to get it. Is there a tutorial and example somewhere? I have searched for it but couldn't find something that exactly fit my need.

[shamlian]

Unfortunately, I don't think there is an API call to get it using the Python SDK, because the raw data are not exposed through that protocol. It is possible to get the state of the cliff sensors as tuple of booleans with get_cliff_sensors() which returns (self.cliff_sensor.left, self.cliff_sensor.front_left, self.cliff_sensor.front_right, self.cliff_sensor.right) (source)