Code becomes stuck when no objects within lidar range

[ShaphanJ]

Thanks for providing the Python code for the CygLiDAR. I was able to implement it on the Jetson Nano. It seems to be working seamlessly for cases in which objects are in the range of the lidar; however, my algorithm gets stuck/returns no data for cases in which no objects are within the lidar maximum range. It seems that the “if Parser(readdata[i]):” line returns false in this case. I’m not sure if the code returns an error in that case, which cannot be handled by the parser. (I see that error codes are listed in the manual but am not sure how/when these errors are generated.) The output returns as soon as an object(s) comes back in range, but the code has to “catch up” to receive real-time data, i.e., a lag occurs afterwards. It would be preferred to read data continuously and/or eliminate the lag in some other way after output returns. I am using the lidar on a vehicle that will be used in an outdoor environment in which obstacles are not present at some intervals. Any help would be much appreciated.

[cygbot]

Hello, @ShaphanJ

First things first, Thank you for your purchasing.

To be more specific about Python code, 'ser.readline()' function is reading packet from CygLiDAR sensor.

If get the packet data from sensor, code is gonna compare each one byte(repeated by readdata's length on each packet data).

For this, we use 'Parser' function. 'Parser' function returns '0x00'(or False, when parsing started) and '0x01'(when finished checking buffer completely) If the function returns 0x01(or True), then we use this buffer, and we provide some converted data, or some methods.

In this buffer, it will include distance data in maximum range, and other values as error code(e.g. ADC Overflow, Saturation)

In Python Code, there's a limiation 'normalizeDistanceLimit(4080)' to distinguish distance conditions, if over this, will return normalizeDistanceLimit(4080) no detail about error condition.

And We suggesting to set low baudrate value, because python couldn't process CygLiDAR response data seamlessly.

To summarize, We recommend use C++ code like ROS Driver. It will performance as you intended compared with Python code.(real time data, reduced delay etc.)

Python just simple test code only for sensor operation or checking some data yet. If you planning like as you commented, not suitable with Python. Thank you.