evora-wheel

Controller and server for the Evora filter wheel, using asyncio.

Installing and running

To run evora-wheel first clone the repository

git clone [email protected]/uwmro/evora-wheel

and then pip-install it

cd evora-wheel
pip install .

To run evora-wheel do

evora-wheel server start

which will start the server as a daemon and detach. To stop the running daemon do evora-wheel sever stop. To run in attached more

evora-wheel server start --debug

Finally, you can run the dummy server for testing as

evora-wheel server --dummy start --debug

Using the Docker image

A Docker image for the arm64 architecture (mainly intended to run on a Raspberry Pi) is built every time a commit is pushed to the repository. You can pull the image as

docker pull ghcr.io/uwmro/evora-wheel:latest

and then run it as

docker run -it --privileged -p 9999:9999 --name evora-wheel -v /dev/bus/usb:/dev/bus/usb  ghcr.io/uwmro/evora-wheel:latest

Note that the container needs to run in privileged mode and the USB buses need to be mounted in the container. We also need to expose port 9999 on which the server runs.

Deploying at MRO

To deploy evora-wheel in a Raspberry Pi at MRO we first need to add udev rules for the Phidget motor device. Add the following test to /etc/udev/rules.d/80-phidget.rules

SUBSYSTEMS=="usb", ACTION=="add", ATTRS{idVendor}=="06c2", ATTRS{idProduct}=="00[3-a][0-f]", MODE="666"

Then start the container with

docker run -it --privileged -p 9999:9999 --name evora-wheel -v /dev/bus/usb:/dev/bus/usb --restart always -d ghcr.io/uwmro/evora-wheel:latest

which will ensure the container is restarted if if crashes or if the Raspberry Pi is restarted.

If the server stops responding the first thing to try is rebooting the Raspberry Pi either physically or ssh'ing to [email protected] and running sudo reboot (no password should be needed for sudo).

If necessary, you can kill the current container with docker kill evora-wheel.

Server commands

evora-whell server start runs a TCP server on port 9999. This server accepts three commands, finished by a newline (\n).

• home will home the filter wheel and move it to filter position 0.
• move <NUM> will move the filter will the filter position <NUM> where <NUM> can range from 0 to 5.
• get will return the current position of the filter wheel.

A valid command will return OK. The get command will return OK,<NUM> is the current filter position. Any invalid or incorrectly formatted command will return ERR.

The server always closes the client connection after returning OK or ERR.