• Portable music-control surface for synths, DAWs, samplers, and live performance rigs.
• Prototype / maker build intended for iterative enclosure and control-layout exploration. -- Designed to look and feel like a rugged field terminal / AKAI MPC X inspired cyberdeck: tactile keys, knobs, display-heavy UI, and a fixed angled upper section.

• Act as a USB MIDI controller when connected to a host computer.
• Support hands-on MIDI control using buttons, keys, encoders, sliders or potentiometers.
• Use the Raspberry Pi 4 for MIDI routing, display/UI, presets, and optional host/software synth behavior.
• Provide visible feedback through LEDs and/or the Pi display.
• Optionally support classic 5-pin DIN MIDI input/output for external hardware synths.

• Raspberry Pi 4 compute base.
• High-current external 5 V input for the cyberdeck electronics and Pi. USB-C is acceptable only with a source/input stage rated for the final load; ordinary computer USB power is not enough.
• Control-panel PCB with joystick/trackball on the left, 3x3 arcade-style momentary button grid in the center, and 3x3 rotary encoder grid on the right.
• Interface from control PCB to Raspberry Pi through USB and/or GPIO/I2C/SPI.
• Main display/touchscreen target: 7 inch lower-power HDMI/USB-touch display, mounted on a fixed tilted upper face.
• Secondary small round touchscreen on the upper face, to the left of the main display and slightly above center so it remains visible above the joystick.
• Three status LEDs above the small round touchscreen.
• Master fader to the right of the main display.
• Two small menu navigation arrow buttons below the main display.
• Three toggle switches/buttons above the 3x3 arcade button grid for parameter on/off functions.
• Optional 5-pin DIN MIDI in/out with opto-isolated input and proper current-limited output.
• No battery module in revision 1; external power only.

Diagram

• Raspberry Pi 4 is the main processor and software environment.
• Pi handles MIDI mapping, USB MIDI, presets, display UI, and higher-level performance modes.

• First schematic target: a microcontroller-based control PCB that talks to the Pi.
• Recommended controller direction: RP2040 or ATmega32U4-class USB-capable MCU for reliable scanning and USB MIDI behavior.
• Inputs: 9 rotary encoders arranged as a 3x3 grid on the right, 9 arcade-style momentary buttons arranged as a 3x3 grid in the center, joystick on the left/top for color-wheel control, trackball on the left/bottom for X/Y parameters, 3 parameter toggle switches/buttons above the arcade grid, 2 menu arrow buttons below the main display, and a master fader on the upper face to the right of the main display.
• Outputs: indicator LEDs, optional LED rings or small auxiliary display.

• Primary: USB MIDI through Raspberry Pi software and/or a dedicated USB-capable control MCU.
• Optional hardware MIDI: 5-pin DIN MIDI input using opto-isolation; 5-pin DIN MIDI output with current-limiting resistors.

• Raspberry Pi 4 requires a robust 5 V supply with high current headroom.
• Control PCB uses 3.3 V logic; either sourced from the Pi header for low-current logic or generated locally from 5 V.
• Battery operation is optional and should be treated as a later power-path design once runtime target and enclosure constraints are known.

• Main display is now the selected Hosyond 7 inch 1024x600 HDMI/USB capacitive touchscreen from https://a.co/d/0hSizIKE, chosen to reduce power draw.
• A small round touchscreen sits next to the main display and may be used for focused status, color-wheel, preset, transport, or mode UI.
• The display section is mechanically fixed on a tilted face; the product shape should resemble an open laptop or cash register, but without hinges.
• Front-panel PCB includes the main hands-on controls and may include status LEDs.

• 5 V power input to Pi and control electronics.
• USB between control MCU and Pi, or GPIO/I2C/SPI from control PCB to Pi if using a GPIO expander architecture.
• Raspberry Pi main display interface: HDMI plus USB touch, or DSI depending on selected display.
• Secondary round touchscreen interface: likely SPI plus touch-controller I2C/SPI, or USB/HDMI if using a complete display module.
• Rotary encoder inputs: 18 quadrature signal lines if wired directly, or fewer Pi/MCU pins if using I/O expanders or encoder interface ICs.
• Arcade button inputs: 9 digital inputs or a scanned matrix.
• Toggle inputs: 3 digital inputs for parameter on/off functions.
• Menu arrow inputs: 2 digital inputs below the main screen.
• Master fader input: 1 analog input unless the selected fader is digital or motorized.
• Joystick inputs: two analog axes plus pushbutton if using a thumb joystick module.
• Trackball interface: USB preferred if using an off-the-shelf trackball module; quadrature or optical sensor interface possible for a custom implementation.
• Optional DIN MIDI input and output connectors.
• Debug/programming connector for the control MCU.
• Test points for 5 V, 3.3 V, GND, reset, and key communication nets.

• Revision 1 is external-power only because the MIDI cyberdeck is intended to be plugged into a computer during use.
• Use the user's planned switched 5.1 V / 5 A / 27 W USB-C wall supply for the prototype system; computer USB is still MIDI/data only.
• The current USB-C input is a 5 V sink-style input and does not negotiate USB-PD. Use a supply/cable combination that actually delivers 5.1 V at the required current.
• Battery charging and runtime are intentionally out of scope for revision 1.

Diagram

• Prototype-friendly design.
• Prefer through-hole or hand-solderable controls where the tactile/front-panel experience matters.
• Use SMD support electronics where appropriate to keep the PCB compact.
• Include mounting holes and connector placement constraints once enclosure dimensions are known.

• Control scanning firmware should support debouncing, encoder acceleration, analog smoothing, and MIDI mapping.
• Raspberry Pi software should expose USB MIDI gadget mode or route MIDI internally using ALSA/JACK/PipeWire tools.
• Firmware should support editable presets and clear GPIO/control mapping documentation.

• Cyberdeck-style enclosure inspired by the supplied reference image: rugged, compact, display-forward, tactile, and visually expressive.
• Overall shape should resemble a cash register or open laptop, with a fixed tilted upper display face and no hinge mechanism.
• Main display/touchscreen: selected 7 inch lower-power HDMI/USB-touch module.
• Small round touchscreen should sit to the left of the main display on the tilted display face, slightly above center so it can be seen above the joystick.
• Overall enclosure shape should be similar to an AKAI MPC X, but with the whole top portion fixed at about 45 degrees rather than only the screen being angled.
• The transition into the angled upper portion may be rounded/smoothed for a more finished enclosure shape.
• Bottom/flat control surface layout: joystick on the left/top, trackball on the left/bottom, 3x3 arcade-style momentary button grid in the center, and 3x3 rotary encoder grid on the right.
• Three toggle switches/buttons sit above the 3x3 arcade button grid.
• Top/angled face layout: 10 inch main touchscreen centered, small round touchscreen to the left and slightly above center, 3 LED status indicators above the small screen, master fader to the right of the main screen, and two small arrow buttons below the main screen for menu navigation.
• No on-device power switch is required for rev 1 because the external plug/supply has its own switch.
• Include internal clearance and wiring route for the Vilros Raspberry Pi case fan; fan power is provided by the control PCB fan header.
• Enclosure should include edge extrusions/lips suitable for a future 3D-printed clip-on dust cover, similar in spirit to a Pelican case lid interface.
• A rear handle behind the screen area is desired for carrying.
• Enclosure target width: roughly 12 to 15 inches.
• Enclosure target depth: similar to or longer than the width to account for both the bottom control surface and tilted display face.
• Enclosure height/thickness can grow as needed to fit the Raspberry Pi 4, display modules, control PCB, wiring, connectors, and service clearance.
• Board likely splits into at least two mechanical zones: Pi/display carrier area and front-panel control PCB.
• Exact board outline, key spacing, display size, and enclosure constraints are still TBD.

• Use the user's existing Raspberry Pi 4 as the compute base.
• Treat the custom PCB as a control/interface board, not as a replacement computer.
• Default first implementation should be USB MIDI oriented, with optional DIN MIDI as an expansion feature.
• Keep the design prototype-friendly for a maker build.
• Prioritize a fixed, angled enclosure geometry rather than a hinged laptop mechanism.
• Treat the joystick as a color-wheel controller and the trackball as an X/Y MIDI parameter controller.
• Lock the current physical layout direction to joystick/trackball on the left, arcade grid in the center, and encoder grid on the right.
• Treat the user-supplied arcade buttons and joystick as definite parts for rev 1 unless an electrical/mechanical issue is found.
• Lock revision 1 to the selected 7 inch lower-power main touchscreen, included trackball, internal fan allowance, and external power only.
• Product references now identified: Hosyond 7 inch 1024x600 HDMI/USB touchscreen, Waveshare RP2350 1.28 inch round LCD board, JESSINIE EC11 20 mm shaft encoders, GODIYMODULES ZH-LED1212-010 illuminated tactile buttons for 3 parameter buttons plus 2 menu arrows, ThunderStick TS-UTB01 trackball, Vilros Pi 4 case fan, and 5.1 V / 5 A switched USB-C supply. The SJ@JX arcade controller links are reference/donor-kit information only until individual button/joystick pinouts are supplied.

• The Raspberry Pi 4 will remain a purchased module, not implemented on the PCB.
• The first PCB will likely be a front-panel/control board connected to the Pi.
• External 5 V power is required for the first revision.
• Exact footprints, pinouts, and enclosure cutouts still need confirmation for the selected 10.1 inch display, Waveshare round display, EC11 encoders, illuminated tactile buttons, arcade buttons/joystick, trackball interface board, fader, knobs, and enclosure CAD dimensions.
• User has supplied PDFs/images for definite arcade buttons/joystick, small screen, rotary encoders, knobs, preferred trackball, trackball alternatives, and overall shape reference; critical dimensions/pinouts must be extracted or verified before committing footprints/enclosure cutouts.

1. Should the device be USB MIDI only, or also include 5-pin DIN MIDI in/out?
2. Do you want the Pi to appear as a USB MIDI device to a computer, or mainly act as a standalone MIDI host/router?
3. Verify the exact mounting-hole pattern and cable exits for the selected 7 inch Hosyond touchscreen.
4. Which exact trackball module should be used from the supplied options?
5. Should the small round touchscreen connect through the Pi directly, or through the control MCU as an auxiliary UI device?
6. What enclosure width should be used as the first mechanical target within the 12 to 15 inch range?
7. Should the master fader be a standard analog slide potentiometer, a MIDI-style digital fader module, or motorized later?

• Initial direction set from user reference image and request: rugged cyberdeck-style MIDI device.
• Updated base architecture to use the user's existing Raspberry Pi 4.
• Added physical layout direction: fixed tilted display face, 7 or 10 inch main touchscreen, small round touchscreen, 3x3 encoder grid, 3x3 arcade button grid, joystick color-wheel control, and optional trackball XY control.
• Confirmed revision 1 direction: 10 inch main touchscreen, included trackball, external power only, and roughly 12 to 15 inch wide enclosure with depth similar to or longer than the width.
• Updated layout per user direction: joystick/trackball moved to the left, 3x3 encoder grid moved to the right, arcade buttons remain centered, top section fixed around 45 degrees, small round screen left of the main screen, master fader right of the main screen, 3 status LEDs, 2 menu arrow buttons, 3 parameter toggles, side/rear power switch, edge dust-cover lip concept, and rear carry handle.
• Updated to selected 7 inch Hosyond lower-power touchscreen, planned 5.1 V / 5 A switched supply, no on-device power switch, and internal fan allowance/header.