Uncle Magic's Liquid Turntable: User Guide#

A motorized platter that turns in time with your music and glows in any colour you choose. Tell it the tempo (from your show software, or by tapping a button), and the platter turns at a speed that matches the beat while a ring of LEDs lights it. Everything can be driven from the knobs on the panel, from a phone or laptop, or from show-control software.

Document status. Written from the design and the firmware built on 2026-10-03. The controls and numbers below are what the firmware is built to do. They have not yet been checked on a fully assembled unit, so expect to adjust a few details (for example, how the platter feels when it starts and stops) once one is running. For how the unit is built, see the Hardware Overview.

1. Quick start#

1. Check the connections, with the power off. The motor cable, the LED ring cable and the panel controls are plugged in, and the network cable is connected (or you have Wi-Fi set up, see section 8).
2. Switch on. The unit starts stopped: the platter does not move and the LEDs show the starting colour solid (red at full brightness unless you changed it). This is normal.
3. Start the platter. Turn the main knob clockwise a few clicks. The platter begins to turn and speeds up smoothly. (Or press Start on the phone page, below.)
4. Give it a tempo. Tap the TAP button in time with the music four times or so. The platter settles to a speed that matches your taps. (If your show software is already sending tempo, the platter follows that and you don't need to tap.)
5. Pick a colour. Turn the HUE knob to choose a colour, SAT for how rich it is, and VAL for how bright.
6. Stop. Press the main knob. The platter slows to a stop.

To control it from a phone, open http://liquidturntable.local/live in a browser on the same network. If that address doesn't work, see section 6.

2. The panel#

The panel also has spare connections for four more knobs. They are not used by the current firmware.

3. Running the platter#

How fast does it go?#

The platter turns one revolution every 12 beats. So the tempo sets the speed:

Above about 204 BPM the platter can't keep up with the beat. It stays at its top speed of 17 RPM, and the phone page shows a warning.

The speed knob#

The main knob sets how much of that tempo speed you want, from 0% to 100% either way:

• 100% turns the platter in time with the music.
• 50% turns it at half that speed.
• Zero stops it. Turning the knob past zero reverses the platter: it slows down, stops, and turns the other way.
• The platter never turns slower than a minimum speed (about 0.6 RPM). Below about 1% on the knob it stops; from about 2% it turns at that minimum and speeds up from there.

Smooth starts, stops and changes#

The platter is heavy, so every change of speed is eased in: starting, stopping, changing tempo, turning the knob, and reversing. From a standstill to 10 RPM takes about a second, and a stop from top speed takes about a second and a half. A reversal slows down, turns round and speeds up again without the motor ever switching off.

Reverse direction (setting)#

If "clockwise" turns the platter the wrong way, tick Reverse motor direction on the settings page (see section 6). This is remembered.

4. Tempo: how the platter knows the beat#

The unit takes its tempo from the first of these that is available:

1. Show software over the network (OSC /bpm). The normal way to run a show.
2. A tempo-controller feed (such as the tempo slider in Resolume). Used if the first is missing.
3. Tapping. Used when neither of the above is sending.

Tempo only changes the speed. It never starts or stops the platter: that is always your decision, with the knob or the phone page.

Tap tempo#

Tap the TAP button, or press Tap on the phone page, in time with the music.

• The first tap just starts the count. From the second tap the tempo is set from the average of your last four taps.
• Taps more than 15 seconds apart start a fresh count.
• Valid tempos are 20 to 500 BPM.
• Tapping only changes the tempo while no show software is sending one. Every tap still sends a "tap" message on the network, so other equipment can follow it.

On the phone page, the line under the tempo tells you where it is coming from: from OSC /bpm, from OSC tempo controller, or local (tap / set).

Starting tempo#

When the unit switches on it uses a starting tempo (120 BPM until you change it on the settings page) until it hears something better.

5. Lighting#

The LED ring shows one colour, set by the HUE, SAT and VAL knobs, by the sliders on the phone page, or by show software. The unit sends the colour to the lighting controller inside (running the open-source WLED software) as soon as it changes, and repeats it every few seconds.

• VAL is the overall brightness. Turning it down also lowers the power the ring draws.
• At switch-on the colour is the starting colour from the settings page (red at full brightness unless you change it). The ring stays dark for the first second or two while the lighting controller starts up.
• Colour temperature (settings page) shifts the whole light warmer or cooler, like a filter: neutral is 6500, lower is warmer and more orange, higher is bluer. It is handy for making white look like tungsten or daylight, and it also tints every other colour the same way.
• Colour comes from this unit, not from WLED's own page. If you change the colour on WLED's web page, the unit puts its own colour back within 10 seconds. Effects and other WLED settings are still yours to use.
• For the one-time WLED settings an installer should make (LED type, power limit, no light at power-up), see Appendix: one-time WLED setup.

6. Controlling it from a phone or computer#

The unit has a small web server. You need a phone, tablet or computer on the same network.

Finding it#

Try these in order:

1. Open http://liquidturntable.local/. This works on Windows 10 and later, Macs, iPhones and iPads, and Linux. Some Android phones don't support it.
2. Look in your router's list of connected devices for liquidturntable and open that address (for example http://192.168.1.50/).
3. As a last resort, connect a USB cable to the controller board and read its log: it prints "ETH got IP" or "Wi-Fi got IP" followed by the address.

The live page (/live)#

Open http://liquidturntable.local/live. It is made for a phone and refreshes about once a second.

The documents on the unit#

This guide and the hardware overview are stored in the unit itself, so they are there when you have no internet. Open the User guide or Hardware link at the top of the settings page (or go to http://liquidturntable.local/docs/USER_GUIDE.html). They are the same documents, in dark colours, and ask for the same password as the other pages.

The settings page (/)#

Open http://liquidturntable.local/. The top shows the current tempo, direction, colour, firmware version and addresses. The page is dark, with tabs across the top: Status, Network, Show (OSC and the lighting controller), Colour, Motor and Security. The tabs are all one form: Save & Reboot, always at the bottom, stores every tab at once and restarts the unit (give it about 10 seconds). The smooth-motion slider on the Motor tab is the exception: it applies and saves as you move it.

Password#

The pages are open to anyone on the network until you set a password. Set one on first use: user name admin, at least 8 characters. After that every page asks for it. Firmware updates are disabled until a password is set.

Other pages: /log shows the unit's recent activity (useful when something is wrong). A bar at the top stays in view as you scroll: Live switches the automatic refresh on and off (turn it off to read or copy a line without the page moving), Clear empties the log, and Save .txt downloads it as a text file. And /update is for firmware updates.

7. Show-control software (OSC)#

The unit listens for OSC messages on UDP port 3335 (changeable), on Ethernet and Wi-Fi at the same time. Numbers may be sent as floats or integers.

The unit also sends two messages, as a broadcast to port 3336 on the local network, so other equipment can react to the tap button:

How "stale" is decided: a /bpm feed that stops for 60 seconds is dropped in favour of the tempo controller; a tempo-controller feed that stops for 1 second is dropped in favour of tapping. When a feed is dropped, the last tempo stays in force until something new arrives. The first /scaleEncoder message after switch-on only records where your control is; it doesn't move the platter.

8. Network setup#

Ethernet is the most dependable link and is used for show work. Plug the unit into your network or router and it asks for an address automatically (DHCP).

Wi-Fi is optional. The unit tries these networks in this order, giving each up to 15 seconds:

1. The network set on the settings page, if any.
2. The networks built into the firmware (set by whoever built it).

If none can be found or joined, it waits 15 seconds and starts again from the top, so the preferred network is picked up as soon as it appears. The log (/log) shows each attempt and why it failed (for example "network not seen" or "wrong password"). Wi-Fi works well within a room; for timing-critical tempo, Ethernet is steadier.

Several turntables on one network#

Every unit is called liquidturntable until you change it, so the first one answers at http://liquidturntable.local/. When a second unit starts, it asks the network whether that name is taken. If so it quietly uses liquidturntable-1, the next one liquidturntable-2, and so on. You can see which name a unit is using at the top of its settings page and of the phone page, and in the log.

Names are first come, first served, so which unit gets which number depends on which was switched on first. To give each turntable a fixed name, open its settings page, type a different Hostname (for example stage-left and stage-right), and press Save & Reboot. Do this once per unit, connecting to them one at a time if need be (by their addresses).

A fixed address. If you want one, set it on the settings page, or (better) reserve an address for liquidturntable in your router.

If you can't reach the unit at all (a wrong fixed address, or a forgotten password): switch the unit off, hold down the TAP button, switch on, and keep holding for 5 seconds. This clears the password and puts Ethernet back on automatic addressing. Other settings are kept.

9. Power and safety#

The unit needs two external DC supplies, plugged into the power connector:

• 24 V (the motor and the unit's own electronics): 1 A or more; 2 A leaves comfortable room.
• 5 V (the LED ring): up to about 11 A when the ring is at full white.

Switching on and off

• Use one switch for both supplies, and do not plug or unplug the power connector with the supplies on.
• After switching off, wait about 3 seconds before switching on again. The electronics need that long to drain.
• Both supplies, started together, produce a brief inrush current. Use a slow-blow fuse (T-type) in the mains inlet.

Hazards and precautions

• Never connect or disconnect the motor cable or the LED ring cable with the power on. A motor is a coil: unplugging it live makes a voltage spike that can destroy the motor driver. The ring cable carries up to about 11 A and can arc as it is made or broken. Switch off, wait about 3 seconds, then change the cable. The same goes for the plug-in modules on the mainboard.
• The supplies run on mains voltage. Bond the earth pin to any metal case, cover all mains terminals, and keep mains wiring away from the low-voltage board. Only a competent person should wire the mains side.
• Keep fingers, hair and cables clear of the platter. It is quiet and slow, and can still pull things in.
• At full white the LED ring is very bright and draws a lot of power. Keep the brightness down in small rooms, and don't look into it.
• The motor driver and the power regulator get warm in use. Leave air gaps around the enclosure.
• Don't press the small BOOT button on the controller module while the platter is running.
• The USB ports on the two controller boards are for setup and updates only; leave them unplugged during a show. When you do connect one, switch the main power on first.

Fuses. The board has two replaceable car-style blade fuses, labelled on the board: F1, 2.5 A (motor and electronics) and F3, 15 A (LED ring). Fit the rating printed beside each. Both take the standard (ATO) size, so the board can't stop you putting them in the wrong way round: check the labels.

10. Care and maintenance#

• Cleaning. With the unit off and unplugged, wipe with a slightly damp cloth. Keep liquid away from the electronics.
• Platter and coupling. The platter is joined to the motor by a flexible coupling. If the platter wobbles or the motor sounds different, check the coupling's grub screws.

• Updating the firmware.

  1. Set a password on the settings page (once).
  2. Open http://liquidturntable.local/update, choose the new .bin file (not the one ending .merged.bin) and press Upload.
  3. The platter stops during the upload and the unit restarts into the new software.

  A new version has to run for 30 seconds with the network up before it is accepted. If it fails to, or crashes, the unit goes back to the previous version by itself at the next restart.

• The log. http://liquidturntable.local/log shows what the unit has been doing since switch-on, with the time of each event. It's the first place to look when something is wrong.

11. Troubleshooting#

12. Specifications#

Appendix: one-time WLED setup#

The lighting controller runs the free WLED software. Whoever builds or installs the unit should set this up once. (The full details are in the project README.)

• Install a WLED build for the ESP32-S3 with USB CDC On Boot disabled, otherwise the unit's colour commands never reach it.
• LED output on pin 4, 178 LEDs, type WS281x, colour order GRB.
• Set the brightness limiter to about 8,000 mA. WLED's default (850 mA) would leave the ring dim.
• Turn off "Turn LEDs on after power up", so the ring stays dark until the unit sends a colour.
• Keep the serial speed at the default 115,200.
• Update the lighting controller over its "USB" port or over Wi-Fi. Keep its "UART" USB port unplugged while the unit is in use.