Learn some morse code!
This is a toy project I am creating to learn and explore the features of balena (disclaimer: I work for balena -- we are encouraged to have projects like this to experience the platform as an end user).
For the hardware, I am using a Raspberry Pi Zero and beginner-friendly Grove components connected via a Grove Base Hat for Raspberry Pi Zero.
The software is written in Python using grove.py, because it seemed to be the best-supported language for my choice of hardware.
This is what I have connected to the Grove Base Hat:
- I2C port: a 16x2 display.
- D16 port: a button.
- D5 port: a red LED.
- A0 port: a thumb joystick (admittedly not the perfect UI choice, but I wanted to use an analog input to enrich my learning experience).
- PWM port: a buzzer.
There's one environment variable used by the mmm service:
MMM_INPUT_TIMEOUT_SECS(default: 10): The input timeout, in seconds. This is how long the system will wait for user input before giving up an returning to the menu. Also, it will consider any input complete after half this much.
Here are some commits that show how to use certain balena features.
- 9b53ffb4feb4d053b7ac79a2faf5f39011da1a5d: Convert from a single-container app to a multi-container app. In fact, the app remains as a single container, but this shows, e.g., how to configure a multi-container app container such that it can access the GPIO.
- 89c9e18dfbbccf09b1a9db5dc0ed684ac3a2c6d3:
Add a volume called
mmm-data. The volume itself is set up indocker-compose.yml; the other changes on the commit implement a feature that makes use of this volume to persist data. - 5b0753a5033911e6490c23d1edad6b752cf3cbee: Read the input timeout from an environment variable, which can be set a number different of ways, like via the balena Dashboard. It's easy to set it for the whole fleet at once, to a specific device only. If set for the whole fleet, it's simple to override it for one specific device.