Joystick Input ECU (Arduino Uno R4 WiFi)

The Joystick ECU is the primary driver-input device. It reads an analog joystick and publishes VSS-aligned JSON to the Raspberry Pi 5 over Wi-Fi/MQTT.

Hardware

Component	Details
Board	Arduino Uno R4 WiFi
Input	Analog joystick module (SunFounder docs)
Connectivity	Wi-Fi (2.4 GHz) → MQTT

The joystick is included in the SunFounder Elite Explorer Kit listed in the Hardware BOM.

Responsibilities

• Read X/Y axis and button state from the analog joystick
• Map joystick positions to VSS blinker and brake signals
• Publish JSON payloads to the MQTT broker on the Raspberry Pi 5

VSS Signals Published

VSS Path	Data Type	Joystick Mapping
Vehicle.Body.Lights.DirectionIndicator.Left.IsSignaling	boolean	Joystick left
Vehicle.Body.Lights.DirectionIndicator.Right.IsSignaling	boolean	Joystick right
Vehicle.Body.Lights.Brake.IsActive	string	Joystick button press (ACTIVE / INACTIVE)

MQTT Publishing Details

Setting	Value
Broker	<pi5-ip>:1883 (default: 192.168.88.100:1883)
Topic	InVehicleTopics

Payload example:

{
  "Vehicle.Body.Lights.DirectionIndicator.Left.IsSignaling": true,
  "Vehicle.Body.Lights.DirectionIndicator.Right.IsSignaling": false,
  "Vehicle.Body.Lights.Brake.IsActive": "ACTIVE"
}

The MQTT-to-gRPC Bridge on the Pi 5 maps this payload to Kuksa Databroker Val/Set updates.

Configuration

Wi-Fi and MQTT Broker

Edit the secrets file before uploading the sketch:

devices/driver-input-ecu-arduino/mcu2-joystick-input/arduino_secrets.h

Set SECRET_SSID, SECRET_PASS, and the broker IP to match your network.

Arduino Libraries

The sketch uses the following libraries (included in the repository):

• ArduinoMqttClient — MQTT connectivity
• zenoh-pico — Optional Zenoh transport (experimental)

Sketch Location

devices/driver-input-ecu-arduino/mcu2-joystick-input/mcu2-joystick-input.ino

Upload via the Arduino IDE (2.x) with the Arduino UNO R4 WiFi board selected.

Signal Flow

Joystick analog input
  → Arduino reads X/Y/button
    → Maps to VSS JSON payload
      → Publishes to MQTT "InVehicleTopics"
        → Bridge converts to gRPC Val/Set
          → Kuksa Databroker stores target values
            → CAN Provider emits BlinkerCommand (0x120) on CAN bus
              → LED ECU drives WS2812 LEDs

See Communication Workflow for the full end-to-end signal path.