aitpi

AITPI

Arbitrary Input for Terminal or a Pi, or Aitpi (pronounced 'eight pi')

Goal

The goal of this project is to provide a simple, but arbitrary, input mechanism for use with a raspberry pi, or a terminal keyboard (maybe more SBCs in the future?!).

This program can be configured with two simple json files.

Supported

The project supports:

• Simple 'buttons'
  • '1 to 1' gpio to button setup on a raspberry pi
  • Non interrupt based key input
  • Interrupt based key input (using pynput)
• Encoders
  • '2 to 1' gpio to encoder setup on a raspberry pi
  • Non interrupt based 2 to 1 key input
  • Interrupt based 2 to 1 key input (using pynput)

Examples

To configure your setup, you can create up to three types of json files:

Command Registry:

A registry of commands that will interact directly with your user program

[
    {
        "type": "normal",
        "input_type": "button",
        "id": "1",
        "name": "command0"
    },
    {
        "id": "1",
        "input_type": "button",
        "path": "../temp/",
        "type": "presets",
        "name": "howdy"
    },
    {
        "id": "1",
        "input_type": "button",
        "path": "../temp/",
        "type": "presets",
        "name": "test"
    },
    {
        "id": "1",
        "input_type": "button",
        "path": "../temp/",
        "type": "presets",
        "name": "another.txt"
    }
]

• name: A UNIQUE identifier that is presented.
• id: The message id sent with each command
• input_type: The abstract functional representation i.e. (for now) a button or an encoder
• type: Category for each command. Must be defined, but is only used to sort commands usefully
• path: Only used for foldered commands. Tells the file path of the represented file.

Input list

The list of all 'input units' that your system uses

[
    {
        "name": "Button0",
        "type": "button",
        "mechanism": "rpi_gpio",
        "trigger": "5",
        "reg_link": "commandName0"
    },
    {
        "name": "Encoder0",
        "type": "encoder",
        "mechanism": "rpi_gpio",
        "left_trigger": "17",
        "right_trigger": "24",
        "reg_link": "commandName2"
    }
]

• This is an array of depth 1, with all your 'input units' listed as dictionaries inside
  • "name": specifies the name of the input unit
    • Valid names: Any string, must be unique among all input units
  • "type": specifies what type of input this unit is
    • Valid types: 'button', 'encoder'
  • "mechanism": This tells Aitpi by what mechanism the input will be watched
    • Valid mechanisms: 'key_interrupt', 'key_input', 'rpi_gpio'
      • key_interrupt: Uses pynput to set interrupts on your keyboard itself
      • key_input: Manual in-code input through the function 'aitpi.takeInput'
      • rpi_gpio: Raspberry pi GPIO input, all input units are assumed to be active low
  • "trigger": The key string or gpio number that will trigger input for a button
    • NOTE: This is only needed if 'type' equals 'button'
    • Valid triggers: Any string, or any valid unused gpio number on a raspberry pi
      • Note strings of more than one char will not work with key_interrupt (pynput)
  • "left_trigger" and "right_trigger: The key string or gpio numbers that will act as a left or right for an encoder
    • NOTE: These are only needed if 'type' equals 'encoder'
    • Valid left_triggers and right_triggers: Any string, or any valid unused gpio number on a raspberry pi
      • Note strings of more than one char will not work with key_interrupt (pynput)
  • "reg_link": This corrosponds to a command from the command registry and will determine what message is sent to your user program

Foldered Commands

Foldered commands allows you to consider all the files in a folder as a 'command' in the registry. This uses the watchdog python package to monitor folders and update on the fly. All commands added will be deleted and reloaded upon program startup.

[
    {
        "name": "Folder0",
        "path": "/path/to/your/folder",
        "type": "<registry_type>",
        "id": "3",
        "input_type": "button"
    },
    {
        "name": "Folder1",
        "path": "/another/path",
        "type": "<registry_type>",
        "id": "4",
        "input_type": "encoder"
    }
]

• This is an array of depth 1 that lists all the folders you want to add
  • "name": Gives a name that you can use to access the json using 'getFolderedCommands'
    • Valid names: Any string
  • "path": Specifies the folder that will be watched
    • Valid paths: Any valid folder on your system
  • "type": This will tell Aitpi where to insert the commands from the folder into your command registry
    • Valid types: Any string
  • "id": When a command is added from the folder, this id will be the command registry 'id' value
    • Valid ids: Any positive int, negative ints are reserved for Aitpi and could produce bad side effects
  • "input_type": When a command is added from the folder, this directly corrosponds to the command registry's 'input_type'

Example usage:

# import the base aitpi
import aitpi
from aitpi import router

# In order to receive messages can either make an object with a consume(message) function
# or just provide a function `def consume(message)`
class Watcher():
    def consume(self, message):
        print("Got command: %s" % message.name)
        print("On event: %s" % message.event)
        print("All attributes: %s" % message.attributes)

watcher = Watcher()

# Here we add a consumer that will receive commands with ids 0,1,2,3,4, these ids are the same
# as defined in your registry json file
router.addConsumer([0,1,2,3,4], watcher)

# We must first initialize our command registry before we can start getting input
aitpi.addRegistry("<path_to_json>/command_reg.json", "<path_to_json>/foldered_commands.json")

# We can add multiple registries, and do not need the foldered commands
aitpi.addRegistry("<path_to_json>/another_reg.json")

# Once we initialize our system, all interrupt based commands can be sent imediately.
# Therefore, make sure you are ready to handle any input in your functions before calling this.
aitpi.initInput("<path_to_json>/example_input.json")

# For synchronous input (not interrupt based) using the 'key_input' input mechanism is desireable
# You can setup a custom progromatic form of input using this (If it is good enough, add it to AITPI!)
while (True):
    aitpi.takeInput(input())