As the proud new owner of an Oak-D-Lite, the sensor was quickly attached to one of my RaspberryPi 3B+ based GoPiGo3 robots for trying out the DepthAI demo (with separate 5v source).

but Questions:
1) Why is the load on my Raspberry Pi 3B+ rising to 3.5 (3.5 of 4 cores in use)? I bought the Oak-D-Lite with the idea it would do all the image stuff, and my robot's processor could just use the results.

2) Why does my depthai_demo.py pop two qt windows, but the Luxonis demo page shows an "all-in-one" window:

my demo:

The website demo:

3) Why does the startup always include a Floating point exception on the first try:

==== Running guided_manual_test.py->Test Cameras ===
$ python3 guided_manual_test.py 
Starting manual test procedure. Press the [ESC] key to abort.
Using depthai module from:  /home/pi/.local/lib/python3.7/site-packages/depthai.cpython-37m-arm-linux-gnueabihf.so
Depthai version installed:  2.13.3.0
libEGL warning: DRI2: failed to authenticate
qt5ct: using qt5ct plugin
Setting up demo...
Available devices:
[0] 184430101175A41200 [X_LINK_UNBOOTED]
Floating point exception
Error while running demo script... Command '"/usr/bin/python3" depthai_demo.py -dev 184430101175A41200 --noSupervisor --guiType qt' returned non-zero exit status 136.
Waiting 5s for the device to be discoverable again...
Setting up demo...
Available devices:
[0] 184430101175A41200 [X_LINK_UNBOOTED]
USB Connection speed: UsbSpeed.HIGH
Enabling low-bandwidth mode due to low USB speed... (speed: UsbSpeed.HIGH)
Creating MJPEG link for ColorCamera node and color xlink stream...
Stopping demo...
=== TOTAL FPS ===
[color]: 3.4
[disparity]: 3.4
[disparityColor]: 3.4
[nn]: 3.5
...

==== My Install (not virtual env) ====

$ uname -a
Linux PIOSLGCY 5.10.63-v7+ #1496 SMP Wed Dec 1 15:58:11 GMT 2021 armv7l GNU/Linux
$ groups
pi adm dialout cdrom sudo audio video plugdev games users input netdev lpadmin gpio i2c spi
$ ps -ef | grep X
root       550   515  0 09:46 tty7     00:00:24 /usr/lib/xorg/Xorg :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
pi        1743   622  0 10:03 ?        00:00:00 /usr/bin/lxsession -s LXDE-pi -e LXDE
pi        1807  1743  0 10:03 ?        00:00:03 lxpanel --profile LXDE-pi
pi        1808  1743  0 10:03 ?        00:00:01 pcmanfm --desktop --profile LXDE-pi
pi        3863  1999  0 10:35 pts/1    00:00:00 grep --color=auto X


git clone https://github.com/luxonis/depthai.git
cd depthai
sudo curl -fL https://docs.luxonis.com/install_dependencies.sh | bash
python3 install_requirements.py 
  - installs opencv-python 4.4, opencv_contrib_python 4.4, depthai 2.13 
  - installs all to /home/pi/.local/bin
python3 depthai_demo.py