adafruit / adafruit_circuitpython_rplidar Goto Github PK

The package description on PyPi for adafruit_rplidar (at https://pypi.org/project/adafruit-rplidar/) states

Eventual goal is for the single module to work with both Linux (via /dev/USB0, etc) and CircuitPython (via a UART instance)

Is there any reason to suspect this goal isn't yet achieved? I'm prototyping a project for eventual raspberry pi deployment in a Ubuntu 18.04 VM, and this seems to work just fine - haven't run into any compatibility problems yet.

As usual, thanks for being awesome!

Starting in 2021, all RPLidar hardware is shipping with firmware 1.29, which breaks this library (error shown is "Incorrect descriptor starting bytes", but that just means that it got no data). Slamtec says that this may be due to the default scan mode being changed to boost mode. They say that they do not support Python(!) and are not intending to fix these libraries. They say it's up to us to fix them ourselves :-(

AFAIK there is no way to downgrade the firmware to a previous version (last known good was 1.27), so I think that until distributors can get Slamtec to help fix these libraries, we have to now consider the RPLidar devices unsupported in Python

There are missing type annotations for some functions in this library.

The typing module does not exist on CircuitPython devices so the import needs to be wrapped in try/except to catch the error for missing import. There is an example of how that is done here:

try:
    from typing import List, Tuple
except ImportError:
    pass

Once imported the typing annotations for the argument type(s), and return type(s) can be added to the function signature. Here is an example of a function that has had this done already:

def wrap_text_to_pixels(
    string: str, max_width: int, font=None, indent0: str = "", indent1: str = ""
) -> List[str]:

If you are new to Git or Github we have a guide about contributing to our projects here: https://learn.adafruit.com/contribute-to-circuitpython-with-git-and-github

There is also a guide that covers our CI utilities and how to run them locally to ensure they will pass in Github Actions here: https://learn.adafruit.com/creating-and-sharing-a-circuitpython-library/check-your-code In particular the pages: Sharing docs on ReadTheDocs and Check your code with pre-commit contain the tools to install and commands to run locally to run the checks.

If you are attempting to resolve this issue and need help, you can post a comment on this issue and tag both @FoamyGuy and @kattni or reach out to us on Discord: https://adafru.it/discord in the #circuitpython-dev channel.

The following locations are reported by mypy to be missing type annotations:

• adafruit_rplidar.py:86
• adafruit_rplidar.py:101
• adafruit_rplidar.py:128
• adafruit_rplidar.py:159
• adafruit_rplidar.py:164
• adafruit_rplidar.py:194
• adafruit_rplidar.py:200
• adafruit_rplidar.py:227
• adafruit_rplidar.py:238
• adafruit_rplidar.py:255
• adafruit_rplidar.py:329
• adafruit_rplidar.py:394
• adafruit_rplidar.py:477
• adafruit_rplidar.py:486
• adafruit_rplidar.py:525

Cant get this library to work with the example code, it just outputs

adafruit_rplidar.RPLidarException: Incorrect descriptor starting bytes

I could just be being an idiot and its my fault, I've tried all the other library's as well with no luck either it throws an exception or it infinitely tells me the buffer is full while outputting no data. has anyone got this library to work on a slamtec A1 with 1.29 firmware.

I see other users are asking this still, and their questions are just being closed.

But it would be nice to use the RPLidar (A1M8-R6)

The results of running the example (all required python libs installed)

pi@raspberrypi:~/Adafruit_CircuitPython_RPLIDAR/examples $ python3 rplidar_simpletest.py
Traceback (most recent call last):
File "/home/pi/Adafruit_CircuitPython_RPLIDAR/examples/rplidar_simpletest.py", line 24, in
for scan in lidar.iter_scans():
File "/home/pi/.local/lib/python3.9/site-packages/adafruit_rplidar.py", line 540, in iter_scans
for new_scan, quality, angle, distance in iterator:
File "/home/pi/.local/lib/python3.9/site-packages/adafruit_rplidar.py", line 445, in iter_measurements
self.start(scan_type)
File "/home/pi/.local/lib/python3.9/site-packages/adafruit_rplidar.py", line 360, in start
status, error_code = self.health
File "/home/pi/.local/lib/python3.9/site-packages/adafruit_rplidar.py", line 328, in health
dsize, is_single, dtype = self._read_descriptor()
File "/home/pi/.local/lib/python3.9/site-packages/adafruit_rplidar.py", line 268, in _read_descriptor
raise RPLidarException("Descriptor length mismatch")
adafruit_rplidar.RPLidarException: Descriptor length mismatch

Any ideas? Thanks

Howdy I've been using this code to run my slamtec rplidar, works well except I'm trying to run it with small display. Therefor, I'm trying to resize the window however, the image doesn't change size, just the window. Please help.

Here's pylint's output:

************* Module adafruit_rplidar
adafruit_rplidar.py:108:0: R0205: Class 'RPLidar' inherits from object, can be safely removed from bases in python3 (useless-object-inheritance)
adafruit_rplidar.py:143:12: W0603: Using the global statement (global-statement)
adafruit_rplidar.py:144:12: C0415: Import outside toplevel (serial) (import-outside-toplevel)
adafruit_rplidar.py:239:8: R1720: Unnecessary "elif" after "raise" (no-else-raise)
adafruit_rplidar.py:314:8: W0107: Unnecessary pass statement (unnecessary-pass)

As far as the useless-object-inheritance goes, @brentru I should be able to do the same thing you did in adafruit/Adafruit_CircuitPython_CursorControl#17, correct?

For global-statement and import-outside-toplevel, here's the offending code:

140        if self.is_CP:
141            _serial_port = port
142        else:
143           global serial
144           import serial

If I understand correctly, this checks if the board is a circuitpython board and if it isn't, it imports serial, although I'm not sure why line 143 is necessary.

For no-else-raise:

239        if len(descriptor) != DESCRIPTOR_LEN:
240            raise RPLidarException("Descriptor length mismatch")
241        elif not descriptor.startswith(SYNC_BYTE + SYNC_BYTE2):
242            raise RPLidarException("Incorrect descriptor starting bytes")

I'm not sure why this is an issue, it makes sense to me why this would be done, although I don't understand this code well enough to make an informed decision on that.

For unneccessary-pass

314    def clear_input(self):
315       """Clears input buffer by reading all available data"""
316       pass

Unless there's some weird python mechanic I don't understand going on here, I think that this would be the right place to raise a NotImplementedError.

Referencing main issue: adafruit/Adafruit_CircuitPython_Bundle#232

Hello. I'm building a robot with the RPLidar, and in every library i use, when i call next(lidar.iter_scans()) it only fetches the scan once, then for the second iteration it just freezes. Any help?

I have RPLIDAR A1M8, but reaction time is extremely poor.
It's kind of usable if an object gets closer. However, if the object gets further away, the reading increases very slowly.
Sometimes it even never recovers if the objects moves quickly.
I'm not sure if I received a defective unit, or it's a library problem.
Has anyone experienced this?

According to Slamtec's website, the motor can operate on variable speeds, however I have seen nowhere where this speed can be changed.

Is this false advertisement, or is there something missing? Furthermore, the motor never stops spinning, even when the .stop() and .disconnect() methods are called.

Re this thread:
https://forums.adafruit.com/viewtopic.php?f=60&t=188371

Please add a new example showing how to use different scan types.

Also - rplidar_simpletest.py appears to be blank. Maybe rename lidar_test.py to match other libs?

SBC: Rpi 3B+
OS: Latest Buster Desktop

I have both a Slamtec A1M8-R5 and a A1M8-R6 which is the latest hardware and firmware (v 1.29)

When I run "display_lidar_pi" using my A1M8-R5, I get the expected Lidar display on my LCD display.

When I run "display_lidar_pi.py" using my A1M8-R6, I get the following error message: "adafruit_rplidar .rplidar exception: wrong body size"

I have searched the IoT for a possible solution to the "adafruit_rplidar .rplidar exception: wrong body size" error, but have experienced no joy.

The A1M8-R5 is two years old and is running an early version of the A1M8 firmware. The A1M8-R6 is running the latest firmware.

Obviously the Adafruit RPLidar module is taking an exception to the latest A1M8-R6 firmware, but has no issue with the A1M8-R5 firmware.

I am using the Adafruit RPLidar module with both the A1M8-R5 and R6 on my Donkey Car platform and have no issues connecting with either A1M8 and collecting data.

Is there a line of code in the "display_lidar_pi.py" program that can be adjusted to overcome the dreaded "adafruit_rplidar .rplidar exception: wrong body size" error?

Here is the complete error message when using the A1M8-R6:

pygame 1.9.4.post1
Hello from the pygame community. https://www.pygame.org/contribute.html
{'model': 24, 'firmware': (1, 29), 'hardware': 7, 'serialnumber': '14342370f79ce5c5d49ae5c9f699f18c'}
Traceback (most recent call last):
File "display_lidar_pi.py", line 55, in
for scan in lidar.iter_scans():
File "/home/pi/.local/lib/python3.7/site-packages/adafruit_rplidar.py", line 508, in iter_scans
for new_scan, quality, angle, distance in iterator:
File "/home/pi/.local/lib/python3.7/site-packages/adafruit_rplidar.py", line 433, in iter_measurements
raw = self._read_response(dsize)
File "/home/pi/.local/lib/python3.7/site-packages/adafruit_rplidar.py", line 261, in _read_response
raise RPLidarException("Wrong body size")
adafruit_rplidar.RPLidarException: Wrong body size