Connected Roomba: wrap up

Posted on Sun 04 August 2019 in hardware

Putting it all together

With everything working I wanted to make sure I didn't have to reset everything anytime an odd decode error occurs, something loses and regains power, etc. For the Feather attached to the Roomba handling this is pretty straight forward. Everything is already running in a super loop, so all I need to add is a try/except block to the while loop and discard errors. Doing the same thing for the Pi was again straight forward, but since it is running Linux I needed to make sure the applications handled failures, and that the scripts restart if the board restarts, the OS bounces, etc.

Similar to the Feather code I wrapped everything in a while loop, added exception handlers, but I also added logging so that I could understand if errors are created by the OS, the code or something else:

import logging
...

LOG_FORMAT = "%(asctime)s:%(levelname)s:%(message)s"
logging.basicConfig(
    filename="/home/pi/logs/button.log",
    level=logging.INFO,
    format=LOG_FORMAT,
    datefmt="%m/%d/%Y %I:%M:%S %p",
)
logger = logging.getLogger(__name__)

...

if __name__ == "__main__":
    while True:
        try:
            ...
        except BaseException as e:
            logger.exception(e)
            pass

And since this is running on Linux setting up cron to handle starting the applications after reboot was one command away.

sudo crontab -e

@reboot cd /home/pi/ && /home/pi/.virtualenvs/lora-pi/bin/python /home/pi/projects/roomba_supervisor/button_listener.py 2>&1 >> /home/pi/logs/button.log
@reboot cd /home/pi/ && /home/pi/.virtualenvs/lora-pi/bin/python /home/pi/projects/roomba_supervisor/sms_listener.py 2>&1 >> /home/pi/logs/sms.log
@reboot sleep 10 && cd /home/pi/ && /home/pi/ngrok http 5000 2>&1 >> /home/pi/logs/ngrok.log
@reboot sleep 20 && curl http://127.0.0.1:4040/api/tunnels 2>&1 > /home/pi/logs/ngrok_details.log

Remote Roomba Demo

Wrapping Up

Since this was my first project interacting with an embedded system I learned quite a bit along the way. Abstractions are something that are useful, but can add bloat and load that won't work in constrained environments. I wasn't able to use the Roomba library I built with the Circuit Playground on the Feather that I connected to the Roomba. CircuitPython made learning and prototyping easy with a REPL and constant connection to the Open Interface. It also allowed me to focus on learning more about the boards and data interactions since I wasn't busy rebuilding my software toolchain for a new environment. That said it has also inspired me to learn more and dig deeper into the embedded world since there are a lot of things I can't user (interupts). There is a lot that I don't know or understand yet, but with the help of some books and boards I am sure I will be busy expanding my understanding for the next few years.

Contact

I really enjoyed working on this project. If you want to reach out feel free to follow up via email or on GitLab.