# OLED Display

ROS 2 node that renders a live dashboard on the I²C OLED display.

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## Dashboard contents

- Robot hostname and IP address
- Ultrasonic range reading
- Camera pan / tilt angles
- CPU and memory usage

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## Subscribed topics

| Topic | Type | Description |
|---|---|---|
| `/ultrasonic/range` | `sensor_msgs/Range` | Distance reading from the HC-SR04 sensor |
| `/joint_states` | `sensor_msgs/JointState` | Current pan/tilt angles |

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## Parameters

| Parameter | Default | Description |
|---|---|---|
| `driver` | `ssd1306` | OLED driver chip: `ssd1306` or `sh1106` |
| `i2c_port` | `1` | I²C bus number |
| `i2c_address` | `0x3C` | I²C device address |
| `width` | `128` | Display width in pixels |
| `height` | `64` | Display height in pixels |
| `rotate` | `0` | Display rotation: `0`, `1`, `2`, or `3` (0°/90°/180°/270°) |
| `refresh_hz` | `2.0` | Display update rate |
| `data_timeout_s` | `5.0` | Seconds before a stale reading is shown as `---` |

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## Hardware

The display connects over **I²C bus 1** (`/dev/i2c-1`), the same bus used by the motor controller and servo driver. Default address is `0x3C`.