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

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Automatic Scanning

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

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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

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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
Use manual scanning when you’ve powered on a new device after RADR’s initial boot scan.

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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

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Connecting to a Device

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

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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

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Connection Parameters

RADR uses optimized connection parameters for responsive control:

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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

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Troubleshooting Connection Issues

  • 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
  • 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
  • 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

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One Device at a Time

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

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Device Registry

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

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Built-in Registry

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

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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.
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.

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Supported Device Types

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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
RADR remembers recently connected devices and attempts fast reconnection when possible.

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Tips

For reliable connections, ensure only RADR is attempting to connect to your device. Close phone apps and other controllers.
If a device appears as “Unknown Device,” it’s still safe to connect—the control interface will be determined by the device’s capabilities.
Keep RADR firmware updated to ensure compatibility with the latest devices.