> ## Documentation Index
> Fetch the complete documentation index at: https://docs.researchanddesire.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Device Scanning

> How RADR discovers and connects to Bluetooth devices

This guide explains how RADR discovers nearby Bluetooth devices and establishes connections.

## Automatic Scanning

When you power on RADR, it automatically scans for nearby supported Bluetooth devices.

### Scan Behavior

* **Duration:** 5 seconds
* **LED Indicator:** Blue pulsing during scan
* **Status Message:** "Searching for nearby devices..."

During the scan:

1. RADR broadcasts as "OSSM-REMOTE" with high transmit power (9 dBm)
2. It searches for devices advertising supported service UUIDs
3. Discovered devices are added to the device list

## Manual Scanning

To start a manual scan:

1. From the main menu, select **Device Search**
2. RADR scans for 5 seconds
3. After scanning, the device list appears

<Tip>
  Use manual scanning when you've powered on a new device after RADR's initial boot scan.
</Tip>

## Device List

After scanning, the device list shows all discovered devices:

* Devices are shown by their advertised Bluetooth name
* If a device has no name, it appears as "Unknown Device"
* The list is scrollable if multiple devices are found

### Navigating the Device List

| Control       | Action                         |
| ------------- | ------------------------------ |
| Right Encoder | Scroll through devices         |
| Right Button  | Connect to selected device     |
| Left Button   | Cancel and return to main menu |

## Connecting to a Device

When you select a device from the list, RADR initiates a connection:

### Connection Status Messages

You'll see these status messages in sequence:

1. **"Initializing connection..."** — Setting up the connection process
2. **"Checking existing connections..."** — Verifying no conflicts
3. **"Attempting fast reconnect..."** — Trying quick reconnection if previously paired
4. **"Creating new connection..."** — Establishing a new Bluetooth connection
5. **"Connecting to \[address]..."** — Connecting to the specific device
6. **"Connected! Setting up device..."** — Connection established, configuring
7. **"Discovering device capabilities..."** — Reading device features
8. **"Device ready!"** — Connection complete, entering control mode

### Connection Parameters

RADR uses optimized connection parameters for responsive control:

| Parameter           | Value  |
| ------------------- | ------ |
| Connection interval | 15ms   |
| Latency             | 0      |
| Timeout             | 1500ms |
| Connect timeout     | 5000ms |

## Connection Failures

If connection fails, you'll see:

* **"Connection failed, please try again."** — General connection failure
* **"Connection limit reached!"** — Too many active BLE connections
* **"Device service not found!"** — Device doesn't have expected services

### Troubleshooting Connection Issues

<AccordionGroup>
  <Accordion title="Device doesn't appear in scan">
    * Ensure the device is powered on and in pairing mode
    * Move within 1–2 meters for initial pairing
    * Close any phone apps that might be connected to the device
    * Power-cycle both RADR and the target device
  </Accordion>

  <Accordion title="Connection fails repeatedly">
    * Ensure no other app or controller is connected
    * Power-cycle the target device
    * Move closer to reduce interference
    * For OSSM: Ensure firmware is 2.0.0 or higher
  </Accordion>

  <Accordion title="Connection drops frequently">
    * Stay within Bluetooth range (typically 10 meters indoors)
    * Reduce interference from WiFi routers and other Bluetooth devices
    * Keep phone apps closed to prevent connection stealing
  </Accordion>
</AccordionGroup>

## One Device at a Time

<Warning>
  RADR can only connect to **one device at a time**. To switch to a different device, you must first disconnect from the current device.
</Warning>

To disconnect and switch devices:

1. From the control screen, press left button to access the menu (when paused)
2. Navigate back to the main menu
3. Start a new device search

## Device Registry

RADR uses a two-tier device registry to identify supported devices:

### Built-in Registry

* Hardcoded support for Research And Desire devices (OSSM)
* Always available and cannot be modified
* Provides full-featured control interfaces

### Dynamic Registry (registry.json)

* Stored in RADR's internal filesystem (LittleFS)
* Contains Buttplug.io device UUIDs and configurations
* **Can be updated via firmware updates without changing the core application**
* This allows faster device support additions

When scanning, RADR checks both registries to identify devices by their Bluetooth service UUIDs.

<Info>
  The dynamic registry enables Research And Desire to add support for new devices more frequently, as it only requires updating a configuration file rather than the entire firmware.
</Info>

### Supported Device Types

| Device Type         | Control Interface                                        |
| ------------------- | -------------------------------------------------------- |
| OSSM                | Full control (Speed, Depth, Sensation, Stroke, Patterns) |
| Lovense             | Vibration-only control (0–16 levels)                     |
| Buttplug.io devices | Varies by device capabilities                            |

## Reconnection Behavior

If RADR loses connection to a device:

1. RADR automatically attempts to reconnect within 2–5 seconds
2. For OSSM: The machine gradually ramps down for safety
3. If reconnection fails, return to the main menu and rescan

<Info>
  RADR remembers recently connected devices and attempts fast reconnection when possible.
</Info>

## Tips

<Tip>
  For reliable connections, ensure only RADR is attempting to connect to your device. Close phone apps and other controllers.
</Tip>

<Tip>
  If a device appears as "Unknown Device," it's still safe to connect—the control interface will be determined by the device's capabilities.
</Tip>

<Tip>
  Keep RADR firmware updated to ensure compatibility with the latest devices.
</Tip>