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Amiga Pendant State Example

Basic Knowledge Requirements

Before diving into this code, here's a quick heads-up on what you'll need to be familiar with:

  1. Python Programming: It's important to have a good grasp of Python, especially with concepts like functions, loops, and classes, since the example utilizes these fundamentals.
  2. Asynchronous Programming with asyncio: Familiarity with Python's asyncio for writing concurrent code using the async/await syntax.
  3. farm-ng Canbus Service Overview: This overview provides a base understanding of the gRPC service the client you create will connect to.

The Amiga Pendant State example is a basic way of showing how to access and decode the PendantState values streamed by the canbus service.

You can either run this example directly on a brain by ssh'ing in, or use your local PC. If using your local PC, it should be either connected to the same local network as the brain or linked to it through tailscale.

The requirements to run this example are to have a farm-ng brain running the canbus service, with a pendant attached to your Amiga. There will be no /pendant stream if your amiga does not have a wired pendant connected.

At the current dashboard firmware release v0.5.0, the PendantState is not published on the CAN bus for pendant alternatives, including Kartech wireless remotes and the on-screen pendant.

PendantState details​

tip

Check out farm-ng-amiga/py/farm_ng/canbus/packet.py or the auto-generated canbus.packet API docs for the latest.

  • x: Joystick [left, right], on range [-1.0, 1.0]
  • y: Joystick [reverse, forward], on range [-1.0, 1.0]
  • buttons: Bit masked integer representing which buttons are pressed
class PendantButtons(IntEnum):
    """Bit field for pendant buttons."""

    PAUSE = 0x01  # Square
    BRAKE = 0x02  # Circle
    PTO = 0x04  # Triangle
    CRUISE = 0x08  # Cross (X)
    LEFT = 0x10  # D-pad left
    UP = 0x20  # D-pad up
    RIGHT = 0x40  # D-pad right
    DOWN = 0x80  # D-pad down
caution

This is the raw output of the pendant, so you should not expect to see x == 0.0 or y == 0.0 when the joystick is "centered", as there is inherent noise in the reading of a joystick axis.

The dashboard filters these values out for vehicle control based on the pendant calibration, but that is not represented in the PendantState.

1. Install the farm-ng Brain ADK package​

2. Install the example's dependencies​

Setup​

cd farm-ng-amiga/
Recommended

Create a virtual environment

python3 -m venv venv
source venv/bin/activate

Install​

cd py/examples/pendant_state
pip install -r requirements.txt

3. Execute the Python script​

info

To run this script from your PC, you need to update the service_config.json by modifying the host field with your Amiga brain name.

Please check out Amiga Development 101 for more details.

python main.py --service-config service_config.json

Expected output​

You should see a printed stream of PendantState, with additional printout of any pressed buttons.