BLE MIDI gateway — bridge Bluetooth LE MIDI controllers to USB MIDI and DIN MIDI, with up to three simultaneous BLE devices, fixed slot routing, and HOST / CLIENT roles for stage and DAWless setups.
Part of the Ash Sound Works custom tools for live and studio — by sound artist and producer Ash (Ahn Sunghoon) · GitHub / Manual
Running cables across a crowded pedalboard or needing remote control for other players is awkward. SPIDER was built around BLE MIDI on a dedicated nRF52840 radio (e.g. nice!nano class hardware): low power, battery-friendly, and focused on wireless MIDI rather than sharing the stack with a desktop OS BLE stack.
- Up to 3 BLE MIDI controllers connected at once
- USB MIDI via TinyUSB — 3 independent virtual MIDI ports (one per slot)
- DIN MIDI — Slot 0 routes to DIN when appropriate (see routing below)
- 7.5 ms BLE connection interval class; low-latency slot timing (~5 ms average response in typical use)
- TX power auto-adjust 0 ~ +8 dBm from RSSI
- Battery monitoring for the unit and connected gear (where supported)
- OLED UI with power-save brightness (USB vs battery profiles)
- HOST and CLIENT modes
| Role | Behavior (summary) |
|---|---|
| Slot 0 (master) | USB ↔ BLE ↔ DIN MIDI |
| Slots 1–2 | USB ↔ BLE |
| Port pinning | Each slot stores MAC + name so devices always map to the same slot regardless of power-on order |
- USB data connected: BLE → USB MIDI (DIN blocked for that path per firmware logic)
- No USB data: Slot 0 → DIN MIDI output
- Slot management: RESCAN, CLEAR SLOT, auto-reconnect
- Uses one slot to join a host
- Remembers first trusted host MAC (save window ~30 s on first connect); optional block for unwanted devices
- Top line: LOW BAT, WEAK SIG, M (DIN active), TX power hints
- Per slot: EMPTY / OFFLINE / CONNECTED
- MIDI traffic: ▽ in / △ out
- Battery: % or N/A if unknown
- 6–4 bars — best; within ~10 m reliable
- 3 bars — stable for normal use
- ≤2 bars — TX power ramps up; maintain connection
- 0 bars — unreliable; move closer
Tip: Keep 3+ bars within ~10 m for dependable live use.
Preferences → Link / Tempo / MIDI
- Input: SPIDER MIDI Port 1, 2, 3 → Track ON, Remote ON as needed
- Output: enable if you send MIDI back to wireless gear
| Slot | USB MIDI port |
|---|---|
| SLOT 1 | Port 1 |
| SLOT 2 | Port 2 |
| SLOT 3 | Port 3 |
BLE adds variable delay; align with audio using Track Delay like any MIDI path. Many setups start around −10 ms ~ −20 ms (often −18 ms) and refine by recording MIDI out + external audio and matching to the grid.
- Connect SPIDER over USB.
- Hold the encoder button for 5+ seconds to enter firmware update mode (USB mass storage / removable drive).
- Copy the released firmware file to the mounted drive; device updates and reboots.
(Exact filename and format follow your published release notes.)
- Band live — multiple wireless controllers into one DAW reliably
- DAWless — Slot 0 → hardware synths via DIN
- Multi-computer — advanced MIDI routing between several hosts (see full manual)
Depending on branch or release:
- Firmware (Zephyr / Arduino / etc. — match your repo)
- Schematics / PCB / case files
- Build and flash instructions
Full wiring, menus, and edge cases: spider-manual.html in the Ash Sound Works bundle.
| Category | Component Description | Qty |
|---|---|---|
| MCU | nRF52840 (nice!nano v2.0 SuperMini) | 1 |
| Display | 0.91" OLED Module (128x64) | 1 |
| Optocoupler | 6N138 High-Speed Optocoupler | 1 |
| Diode | 1N4001 Rectifier Diode | 1 |
| Capacitor | 100μF Electrolytic Capacitor | 1 |
| Input | EC11 Rotary Encoder w/ Push Switch | 1 |
| Connectors | PJ-320A 3.5mm Stereo Jack | 2 |
| Power | SS-12F23 Slide Switch | 1 |
| Resistors | 220Ω (x2), 330Ω (x2), 150Ω, 1kΩ, 4.7kΩ, 10Ω, 30Ω | 9 |
- Full manual:
spider-manual.html - Other projects: github.com/nunosmash
- BLE performance depends on environment, antennas, and interference — always test before a show.
- Verify DIN polarity (Type A/B) when connecting legacy MIDI gear.
- DIY: observe battery and USB power safety.
See the LICENSE file in the repository root.