Build librealsense for T261/T265 on Raspberry Pi 4 running Ubuntu 22.04 in the big year 2025

building_librealsense.md

Realsense for T261

Building Realsense in this Version in the big 2025 is painful to say the least Since T261's software support is crap, I had to build an older version of librealsense that still supports T261 and use an older version of Ubuntu to get it working.

My System Info

samad@imu:~/rover$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 22.04.5 LTS
Release:        22.04
Codename:       jammy

samad@imu:~/rover$ uname -r
5.15.0-1087-raspi

If your system info is different, you might need to adjust some steps accordingly.

Downloading

We need this specific version of librealsense. Download and extract it.

wget https://github.com/IntelRealSense/librealsense/archive/refs/tags/v2.51.1.zip
unzip v2.51.1.zip
cd librealsense-2.51.1

Installing Dependencies

Make sure you have the required dependencies installed.

sudo apt-get update
sudo apt-get install git libssl-dev libusb-1.0-0-dev pkg-config
sudo apt-get install libgtk-3-dev libglfw3-dev libglfw3
sudo apt-get install libgl1-mesa-dev libglu1-mesa-dev
sudo apt-get install libasound2-dev libpulse-dev
sudo apt-get install libudev-dev libx11-dev libxinerama-dev libxc

Check with chatgpt incase i missed a few dependencies.

Patches to the source code

While building it ( steps for building later) you'll run into some problems with gcc 10+ since this library was build ages ago??

Patch 1:

While building with a recent compiler you'll see an error like

librealsense-2.51.1/src/libusb/libusb.h:10:82: error: extended character ‘ is not valid in an identifier
   10 | /usr/include/libusb-1.0/libusb.h:736:4: warning: ISO C++ forbids zero-size array ‘dev_capability_data’ 

Find the file in that's throwing this error (likely librealsense-2.51.1/src/libusb/libusb.h:10:82 ) and replace ‘ with ' in 3 places. See this patch to understand what to edit in the file.

Patch 2:

While building examples you'll also see an issue like this

"undefined reference to `gluPerspective'"

Use this comment on github to patch the CMakeLists.txt file in the root of the librealsense source code.

Building

Now we can build the library.

cd librealsense-2.51.1 // If not already there
mkdir build && cd build
cmake .. -DBUILD_EXAMPLES=ON -DBUILD_WITH_TM2=ON -DFORCE_RSUSB_BACKEND=ON -DCMAKE_CXX_FLAGS="-Wno-pedantic"
make -j 4

Adding Udev Rules

To allow non-root access to the T261 device, we need to add udev rules.

cd librealsense-2.51.1 // If not already there
sudo ./scripts/setup_udev_rules.sh

Testing the Installation

After building, you can test the installation by running one of the examples.

Plug in your T261 device and run the enumerate devices tool:

cd librealsense-2.51.1/build/tools/enumerate-devices
./rs-enumerate-devices

The output should look like

Device info: 
    Name                          :     Intel RealSense T265
    Serial Number                 :     908412110976
    Firmware Version              :     0.2.0.951
    Physical Port                 :     2-1-2
    Product Id                    :     0B37
    Usb Type Descriptor           :     3.1
    Product Line                  :     T200

Stream Profiles supported by Tracking Module
 Supported modes:
    stream       resolution      fps       format   
    Fisheye 1     848x800       @ 30Hz     Y8
    Fisheye 2     848x800       @ 30Hz     Y8
    Gyro         N/A            @ 200Hz    MOTION_XYZ32F
    Accel        N/A            @ 62Hz     MOTION_XYZ32F
    Pose         N/A            @ 200Hz    6DOF

Troubleshooting

When you plug in the T261 device, run the following command to check if the device is recognized:

lsusb

You may see an entry similar to:

Bus 001 Device 009: ID 03e7:2150 Intel Myriad VPU [Movidius Neural Compute Stick]

If not, try plugging the device into a different USB port and ensure that your udev rules are correctly set up. Also, a reboot might help after setting up udev rules.

Run the enumerate devices tool again to see if the device is detected.

After running it, you should see output similar to:

lsusb
Bus 002 Device 002: ID 8087:0b37 Intel Corp. Intel(R) RealSense(TM) Tracking Camera T265