Coffee-Tag Machine

This readme mainly describes how to install and use this python package on the raspberry and how to develop it.

Important

It is possible to use other technics to install/dev/use this package (e.g. conda) but the officially supported ones are pipx in production and virtual environment in development.

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Usage

In production, the app can be launched with the coffee_tag cli. When in dev, you need to do python -m coffee_tag.

The nominal command is coffee_tag COFFEE_PRICE PATH_TO_DB. Additional arguments and flags are described with the -h argument.

Note

In production, it is recommended to use an absolute path for the database to avoid any error.

Production Setup

Initial configuration of the Raspberry PI (do once)

Wiring

Usage	Pin	Left Signal	Right Signal	Pin	Usage
	1	3V3 Power	5V Power	2	PN532 (red)
PN532 SDA (yellow)	3	GPIO2 (SDA1)	5V Power	4	SCREEN (red)
PN532 SCL (green)	5	GPIO3 (SCL1)	GND	6	SCREEN (brown)
	7	GPIO4	GPIO14 (TXD0)	8	JURA RX (blue)
JURA (black)	9	GND	GPIO15 (RXD0)	10	JURA TX (brown)
	11	GPIO17	GPIO18 (PWM0)	12
	13	GPIO27	GND	14	PN532 (brown)
	15	GPIO22	GPIO23	16	JURA (white)
	17	3V3 Power	GPIO24	18
	19	GPIO10 (MOSI)	GND	20
	21	GPIO9 (MISO)	GPIO25	22
	23	GPIO11 (SCLK)	GPIO8 (CE0)	24
	25	GND	GPIO7 (CE1)	26
	27	GPIO0 (ID_SD)	GPIO1 (ID_SC)	28
	29	GPIO5	GND	30
	31	GPIO6	GPIO12 (PWM0)	32
	33	GPIO13 (PWM1)	GND	34
	35	GPIO19 (PCM_FS)	GPIO16	36
	37	GPIO26	GPIO20 (PCM_DIN)	38
	39	GND	GPIO21 (PCM_DOUT)	40

Software

When creating the image, select Raspberry PI 2 and choose the 32-bit desktop image. Also edit /boot/firmware/config.txt and change the following lines:

dtparam=i2c_arm=off
dtparam=spi=off

Finally, to ensure the Raspberry PI 2 stays up to date (literally), add a cron task (with sudo crontab -e):

0 1 * * * date -s "$(wget --method=HEAD -qSO- --max-redirect=0 google.com 2>&1 | sed -n 's/^ *Date: *//p')"

Note

This is currently required as the IT blocks NTP requests.

To be able to download the app, add the relevant pypi index in pip.conf:

[global]
extra-index-url =
    https://www.piwheels.org/simple
    https://__token__:[token]@gitlab.ensta.fr/api/v4/groups/3178/-/packages/pypi/simple

Note

The token needs to be created here with read_api scope and developer role.

Install the dependencies with

apt install -y python3-tk python3-pillow libjpeg-dev

Then install pipx with the official tutorial. Finally, install this app with pipx install coffee-tag.

That's it, the setup is ready to be used. See Usage to use it!

Upgrade the app (for every new version)

First, close the app and make a copy of the database. Then pipx upgrade coffee-tag and finally restart the app.

Development Setup

To create a virtual environment, perform the following commands:

apt install python3-tk python3-pillow libjpeg-dev # install the linux dependencies
python3 -m venv .venv # create a virtual env 
source .venv/bin/activate # activate the virtual env (to do everytime)
pip install -r requirements.txt # install dependencies

While developing, be sure to use the argument --dev to prevent the app from trying to connect to the rfid reader.

At the time of writing (16/12/25), the recommended command to use is coffee_tag 0.25 coffee.db --no-authentication --dev --verbose --read-only.

Docs

• Test RFID reader
  • 13.56 MHz NTC reader
  • Doc here or here
  • 125 kHz reader

Gitlab CI

The python package is automatically built when a branch is merged on main, a release is created here, and it is published to the GitLab pypi index to be available for download.

The pipeline first builds the package with the build module, then with GitLab API and the twine module publishes the release and the package. Please refer to .gitlab-ci.yml for the exact details of the pipeline.

Note

The DSI (IT service) doesn't provide any runners on the GitLab. The U2IS Runner was added to the group.

Tip

To allow releases creation, create a token here with the permission api, write_repository with the role Developer, then create the variable

RELEASE_TOKEN here.