# Probing Intel Realsense LIDAR with voxl-mapper

Source: https://forum.modalai.com/topic/2306/probing-intel-realsense-lidar-with-voxl-mapper
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2023-06-22 19:56:50 UTC by Zachary Lowell 0
Replies: 10 · Views: 2577

## Zachary Lowell 0 · 2023-06-22 19:56:50 UTC

Hi!

I currently have some code written that pipes some lidar data from an intel realsense to voxl-mapper. AKA all the pipes that the modal TOF camera uses in voxl-camera-server, I am writing to as well. I am able to see the point cloud and tof ir image and depth image in voxl-portal, but when I run voxl-mapper I immediately am hit with:

ERROR in pipe_server_write_point_cloud, received NULL data pointer
ERROR in pipe_server_write_point_cloud, received NULL data pointer
ERROR in pipe_server_write_point_cloud, received NULL data pointer
ERROR in pipe_server_write_point_cloud, received NULL data pointer
ERROR in pipe_server_write_point_cloud, received NULL data pointer
ERROR in pipe_server_write_point_cloud, received NULL data pointer

I am printing data on both ends and what is going from the intel realsense is clearly making it to voxl-mapper, but unsure why I am getting this error since I am writing the point cloud from my custom code. Is voxl-mapper also trying to probe the realsense?

Thanks!
Zach

## Reply by admin (ModalAI staff) · 2023-06-23 14:28:55 UTC

Hey @Zachary-Lowell-0 ,

So you have a custom driver for realsense going right?  We don't have anything going for realsense so we aren't trying to probe anything (assuming you mean access the interface (not sure if it's UART/USB/I2C etc) but portal definitely isn't going to be interacting with devices like that.

## Reply by modaltb (ModalAI staff) · 2023-06-23 14:29:27 UTC

Oops, wrong login on last response ;)

## Reply by wilkinsaf · 2023-06-23 16:19:22 UTC (in reply to modaltb)

@modaltb Wanted to reply here. We figured out the issue. We needed to pipe over additional information to voxl-mapper. Zach has more details in case anyone is curious

## Reply by robertshmurda · 2023-11-06 02:22:13 UTC

@Zachary-Lowell-0 Hi, this is a reply out of nowhere but our project also involves integrating a LiDAR (not the RealSense) with the VOXL2. We have not yet started the process, but I was wondering if your project involved the replacement of the TOF sensors or just piping the LiDAR data to voxl-mapper and bypassing the data sent by the built-in sensors. I also want to ask about the code you used and problems you encountered if it's no trouble to you, it would be substantially helpful for our project.

## Reply by Zachary Lowell 0 · 2023-11-21 23:27:12 UTC

@robertshmurda this has been done by myself by piping the point cloud directly into the MPA.

You can grab the point cloud from whatever api/sdk exists for your lidar and as long as you can get it into the correct struct to pass through the MPA, you can do that and stream it directly to voxl-mapper. 

If you have more questions - feel free to email me zachary.lowell@ascendengineer.com and we can hop on a call or something.

## Reply by robertshmurda · 2023-12-07 20:44:38 UTC (in reply to Zachary Lowell 0)

@Zachary-Lowell-0 Thanks Zach, went ahead and sent you an email.

## Reply by K.Stute · 2024-02-28 14:30:52 UTC

Hi @Zachary-Lowell-0,
sorry to reactivate this old topic but I'm stuck trying to get a real-sense D455 to work over the USB-port of the voxl2. Since apparently the real-sense products are not support by modalai I'd like to know how you got the camera connected and working.
Thanks in advance!

## Reply by wilkinsaf · 2024-02-29 14:54:51 UTC (in reply to K.Stute)

@K-Stute we had to write a customer driver to handle it

## Reply by K.Stute · 2024-03-03 15:25:23 UTC (in reply to wilkinsaf)

@wilkinsaf any chance that this driver is open source? Would save me some time^^

## Reply by wilkinsaf · 2024-03-06 21:52:43 UTC (in reply to K.Stute)

@K-Stute I wish, but it is not.