Hardware and Connections

Minimum equipment

• Raspberry Pi 4 or Raspberry Pi 5;
• high-quality microSD card of at least 8 GB;
• a stable power supply suitable for the specific Pi;
• an Ethernet cable to the Art-Net network;
• a computer or phone for the CUE/IO web control.

Audio, LTC, GPIO, and DS3231 are optional. The software continues to operate when these features are not installed, but the corresponding capability will be disabled or shown in a warning state.

Network and access

CUE/IO supports four practical network topologies:

1. isolated Ethernet or USB Ethernet used only for the Art-Net network, with no internet access;
2. one Ethernet interface for both Art-Net and internet access;
3. Ethernet for Art-Net and Wi-Fi for internet access;
4. two Ethernet interfaces—one for Art-Net and one for internet access and management.

Main ports:

Art-Net Broadcast requires correct IP address and subnet configuration. Use Unicast targets on more complex or routed networks. Do not create an internet-accessible port-forwarding rule to CUE/IO.

Configurable .local address

Avahi publishes the selected hostname as an mDNS address. The default is:

http://cueio.local/

.local works only within the local network and also depends on mDNS support on the client device. The IP address always remains an alternative.

To distinguish multiple CUE/IO units on one network, open Settings → Network → Management access, enter a different Device name on each unit, and press Save .local and access. The name may be entered with a .local suffix; CUE/IO safely normalizes it to one hostname. After the transaction succeeds, the name appears in the browser title, mobile header, and desktop shell. Open the displayed clickable http://<name>.local/ address. Saving deliberately validates and applies the adjacent fallback Wi-Fi configuration too; if no dedicated AP adapter is present, select a valid adapter or explicitly turn the fallback AP off before saving.

Fallback Wi-Fi access point

The fallback AP is intended for recovery when the normal IP address is unknown or the local network is unavailable. It is enabled by default in a clean CUE/IO installation and, during first start, attempts to reserve an available Wi-Fi adapter that supports AP mode. Configure it under Settings → Network → Management access.

• the AP is created only on a Wi-Fi interface that supports AP mode;
• CUE/IO deliberately does not disconnect an existing user Wi-Fi connection;
• in a factory installation, CUE/IO Setup is initially an open local recovery network without a password;
• after the first connection, use Settings → Network → Management access to enable WPA2 and set your own password;
• if the only built-in Wi-Fi interface is used for internet access, the fallback AP may require a second USB Wi-Fi adapter;
• check the current SSID, password status, and direct address in the CUE/IO Network section;
• if no adapter can be used safely, CUE/IO continues to operate and the status clearly reports that fallback Wi-Fi is waiting for a separate adapter.

Network IP changes are validated first and then saved persistently to the selected Ethernet port in a single operation. Fallback Wi-Fi and the exact <device-name>.local address shown under Management access provide an independent management path: if the new Ethernet address is not reachable, connect to fallback Wi-Fi, open the displayed .local or recovery URL, and correct the port settings.

Art-Net and experimental sACN

In RECORD mode, select the exact interface on which DMX arrives. The real-time monitor can listen automatically on all interfaces, but a recording session uses the selected interface and a single owner of the UDP socket.

PLAYER, Timecode cues, and trim output preview send datagrams to the configured Broadcast or Unicast target.

• for every show with type manual, the output stored with the show is authoritative. A Manual-show Unicast route uses exactly one IP stored with that show, while Manual-show Broadcast uses the configured broadcast address; both ignore the global unicast list. This applies to fixed scenes, effects, and imported Manual shows;
• all other shows use the global Settings → Network → Art-Net unicast targets. One or more valid addresses replace broadcast; an empty list or no valid address restores the configured broadcast;
• recorded, imported, or generated describes show origin. The stored show type, not its origin, selects the routing behavior.

Change a Manual show's target from Manual show or Edit in the PLAYER list, under Art-Net output. Change global targets only in Network settings and store them with Save and apply.

Before testing on a real lighting network:

1. select the correct interface;
2. check the IP address, subnet, and Broadcast address;
3. open Monitor and check the universe and channel;
4. run a short rainbow test only if the connected equipment may safely receive test DMX.

Art-Net is the complete, primary CUE/IO protocol. The current sACN path only forwards raw UDP data directly: it does not parse E1.31 universes for DMX statistics, and it does not generate an sACN blackout packet. Do not use it as a safety-critical replacement for full sACN support without a separate test on the real network.

USB audio

CUE/IO uses ALSA device identifiers such as plughw:1,0. Device numbers may change after reconnecting USB devices or restarting, so an audio device is not preselected in the production IMG.

Recommended sequence:

1. connect the audio interface before starting CUE/IO;
2. select the input and output under Settings → Audio;
3. run the audio test;
4. enable audio in RECORD mode only after a successful test;
5. for Timecode, select the input that actually receives LTC.

If audio is enabled but the selected input is unavailable or busy, recording or Timecode does not start. The PLAYER volume slider changes an ALSA mixer control, not the audio file. If amixer or a suitable mixer control is unavailable, playback may still work, but volume control will show a warning.

LTC Timecode

LTC is an audio signal. CUE/IO prepares and checks the audio input before waiting, after which ffmpeg and ltcdump decode the selected left or right channel.

Configure:

• a frame rate of 1–60 FPS;
• LTC channel left or right;
• signal-loss timeout of 0.1–30 seconds;
• audio startup timeout of 0.5–30 seconds;
• cue start/end Timecode values in HH:MM:SS:FF format.

Do not connect the LTC audio signal to Raspberry Pi GPIO. It must reach the selected audio interface line input at a level that is safe for the hardware.

GPIO

The GPIO monitor uses BCM numbering, not physical connector position numbers. Four inputs can be configured with a HIGH/LOW active level, contact debouncing, Play/Stop actions, and ignore conditions.

GPIO is intended for logic-level inputs. Do not connect a DMX line, relay coil, 5 V, or higher voltage directly to Pi GPIO; use a suitable galvanically isolated or level-shifting interface. If you are unsure about the wiring, ask an electronics specialist.

For Pi 5, use only a GPIO interface tested with the CUE/IO image. If GPIO diagnostics show an error, contact the installer or CUE/IO support.

DS3231 RTC

RTC is optional. When installed, CUE/IO can read the RTC at startup and update it from system time once reliable NTP is available. Without an RTC, Scheduler continues to use the system clock, but time may be unreliable after a long, complete power-off period without internet access.

The I²C connection and system configuration are hardware-specific. An authorized technician must install the RTC in accordance with the particular Pi model and board.

Storage and power

CUE/IO checks free space before recording. The default thresholds in the production image are 1024 MB for starting and 512 MB for critical stop. During recording, free space is checked every five seconds.

Never disconnect power during an active recording. For everyday shutdown, use Settings → Device → Shut down and wait until the Pi has shut down correctly.