This is what it does:

That was the problem. I figured it out like 2 minutes after I submitted this post for approval 😂.

Thanks Alex!

Thank you! I've had so much fun working with Bittle, I am eager to keep exploring what can be done with the platform.

I see, it looks like the ESP32 is the way to go. But I'd like to still use the raspberry pi for ROS2 interfacing. Basically, I have the high level planning, such as overall heading in ROS2, but have the adaptive balance correction on the ESP32, if that makes sense.

What are the limitations of the gyroscope correction to joint angles to maintain the center of mass? Can you direct me to where this is implemented in the source code on the NyBoard? I've also been wondering if further refinement of stability and gait calls for the BiBoard, but I'm curious, do you know if a raspberry pi can interface with it? I gather that it would have to be through USB connection rather than GPIO pins.

I'm intrigued by this: The robot proprioception is demanded to an inertial measurement unit (IMU) and to joint encoders. From Robot Feet, part 2. I wonder what the proprioception limits are of the NyBoard? From a philosophical perspective, you don't need to train a wheel to roll, but every animal needs to learn to walk. My gut feeling is that gait design combined with adaptive control based on sensor input is the way to achieve universal stability.

Is the current gait with the foot sliding used because it is more stable on smooth surfaces?

This is on carpet without friction tape. This is also unstable, but not as bad as with friction tape.

This is on carpet with friction tape on the feet. It is the most unstable configuration

This is on tile without friction tape. It is the most stable configuration.

This is bittle on tile with friction tape on the feet. It is less stable than without friction tape.

Update for Pi Zero 2w: I've found that setting the image size to 320x240 with jpeg_quality at 20 provides low latency streaming.

I'm so glad others are using it!

I hope to implement ORB SLAM eventually also. I've been fighting with video latency quite a bit. It is better on a Pi 4 or 5 than the 0 2W, but still an issue eventually. It has been a challenge to find exactly where the hangup is. By adjusting compression, queue sizes, and image size I have been able to get reliable low latency for a few minutes, but typically the latency increases over time. If you try the Pi 4 or 5, you'll need a separate power source for them, or hard wire in a voltage regulator into the bittle battery. The Nyboard voltage regulator can't handle the power requirements for them.

How is the video streaming latency with this setup? Is that a Pi Zero 2w or Zero?

I also had issues getting the serial communication to work on ROS melodic following that article. A good place to check in his repository is his bittle_driver.py script. I had to change the baud rate to 115200 to get it to work. I have also detailed instructions on raspberry pi setup here: https://github.com/gravesreid/autonomous-bittle.git I created these instructions after many hours of trial and error to get serial communication working from the Pi to Bittle. I have tested that they work on raspberry pi zero, zero 2w, pi 4, and pi 5. A key issue that I've noticed recently is that port ttys0 does not always work, I suspect this is due to an update to the raspberry pi setup. To work around this, I disabled bluetooth and modified the scripts to use port ttyAMA0. Details for this are also in the instructions. As far as ROS goes, I have recently made a ROS2 package that has the same functionality as the tutorial you linked, with the addition of control through a generic USB controller, such as this one: https://vilros.com/collections/retro-gaming/products/vilros-snes-classic-weighted-usb-gamepad-set As well as video streaming through a USB camera or Raspberry pi camera. The repository is here: https://github.com/gravesreid/bittle_ros2.git If you want to use the usb controller functionality, you'll also need the messages package I made for it: https://github.com/gravesreid/bittle_msgs.git I'm actively working with and updating this package.

I did start with that ROS wrapper. I was able to get the example with the predefined set of commands to run, but had issues with getting the serial protocol to work. I would be happy to merge the two into the ROS chapter of your doc. I also have a repo that I made for setting up Bittle with a raspberry pi zero 2w. The readme outlines the step I took, and there are video streaming and autonomous vision based command scripts. https://github.com/gravesreid/autonomous-bittle

I got it to work. Thank you!

I see that I can add a task with tQueue->addTask('token', 'skill', 'time), but is there a way to do this with the function send(port, task, timeout=0) in ardSerial.py?