THE VOID BUILD
UV-C + Ambient Lighting
UV-C sterilization and five ambient light modes in a simple, low-power package. Same dome as all Void variants, plus LEDs and a hardware safety interlock.
3D PRINTABLE FILES
Download & Print
All parts print on a standard FDM printer with a 220x220mm bed (split dome) or 220x220x270mm+ build height (full dome). PETG recommended for humidity resistance.
Substrate Platform
Drainage platform with 6 drain slots and 8 drainage ribs. Sits inside the base housing on the support ledge.
Smallest and fastest part. Print first as a calibration test for printer adhesion and bed leveling.
Download STLVent Cap Set
Set of 4 vent caps with snap-fit tabs. Insert into dome exhaust holes for adjustable airflow.
Fine layer height (0.16mm) is important for smooth snap-fit tabs. Solid infill since the parts are very small.
Download STLBase Housing
Low-profile electronics enclosure with mounting points for ESP32, BME280, fan, humidifier, and cable routing channels.
Compact base (R/φ² height ratio). Use tree supports to minimize interior contact marks. Print upright with open-top facing up.
Download STLDome (Full)
One-piece cloche dome with golden ratio proportions. Requires 270mm+ build height. Strongest option with no glue joint.
Requires 220×220×270mm+ build volume. Print base-down (open end on bed). If your printer is shorter, use the split dome option instead.
Download STLDome Upper (Split)
Arch cap of the split dome. Hemisphere section that sits atop the straight wall lower.
Print cut-face down. The flat cut face provides a stable base. Alignment step ring interfaces with dome lower.
Download STLDome Lower (Split)
Straight wall section of the split dome. Tall cylindrical section with seating lip for base channel.
Print base-down (seating lip on bed). Glue to upper half with medium CA + accelerator on alignment step ring.
Download STLBILL OF MATERIALS
Parts List
Electronics and hardware for The Void build. No microcontroller needed — this variant uses discrete LED drivers and a simple button for mode cycling. Prices are estimates.
Drives UV-A + Blue LED strings from 5V rail
Dome presence interlock — wired IN SERIES with UV-C power path
Q1: UV-A, Q2: Blue, Q3: UV-C
Silicone jacket for flexibility
Required for split dome; optional for magnet
Some links are affiliate links. Purchases help support the project at no extra cost to you.
HOW IT WORKS
Circuit Architecture
No microcontroller. Five light modes, automatic UV-C shutoff, and a hardware safety interlock — all with discrete components.
CH224K USB-C PD Sink IC
Power negotiation
Negotiates 5V from any USB-C source. Handles the PD handshake so any phone charger works.
PT4115 LED Driver
Constant-current LED drive
Delivers a fixed 20mA per LED string regardless of voltage fluctuations. Drives both UV-A and Blue strings.
NE555 Timer #1
12-hour light cycle
Astable mode timer that alternates grow lights on a 12h on / 12h off cycle matching natural fruiting schedules.
NE555 Timer #2
15-minute UV-C auto-shutoff
Monostable mode timer that limits every UV-C sterilization cycle to exactly 15 minutes. Hardware safety guarantee.
Reed Switch
Dome presence detection
Normally-open glass reed switch wired IN SERIES with UV-C power. Dome removal physically cuts UV-C current.
Mode Button
Light mode cycling
Tap to cycle four light modes. 3-second hold triggers UV-C sterilization via RC delay circuit.
LIGHT MODES
Five Operating Modes
Cycle through four grow-light modes with a button tap. Hold for three seconds to trigger UV-C sterilization. UV-C never runs simultaneously with grow lights.
| Mode | UV-A | Blue | UV-C | Trigger |
|---|---|---|---|---|
| Void Glow | Button tap (default) | |||
| UV Only | Button tap | |||
| Blue Only | Button tap | |||
| Off | Button tap | |||
| Sterilize | 3-second hold (dome seated) |
The 12-hour timer automatically cycles grow lights (modes 1-3). UV-C sterilization is always manually triggered and limited to 15 minutes by hardware.
BUILD STEPS
Assembly Guide
Five phases from inspection to final dome assembly. Estimated total build time: ~45-60 minutes (excluding print time).
Pre-Assembly Inspection
~5 minInspect all printed parts for warping, test-fit vent caps, verify platform seating, and check connector cutouts.
Magnet & Reed Switch
~10 minInstall the dome magnet and base reed switch that form the UV-C hardware safety interlock. Mandatory continuity test before proceeding.
SAFETY NOTE
The reed switch is the UV-C safety interlock. You MUST verify it closes when the dome is seated and opens when removed.
LED & Electronics Wiring
~30-40 minWire UV-A and Blue LED strings through PT4115 driver, UV-C LED through reed switch interlock, 555 timers, mode button with RC delay, and CH224K power supply.
Power-On & Interlock Test
~10 minFirst power-on, verify 5V rail, test all four light modes, and perform the mandatory UV-C interlock safety test.
SAFETY NOTE
STOP before dome assembly. Trigger UV-C, then lift the dome — the red indicator must turn off immediately.
Final Assembly
~5-10 minGlue split dome halves (if applicable), insert vent caps, seat dome onto base with alignment notch, and verify stability.
For detailed wiring diagrams, see the full circuit reference on GitHub.
SAFETY
Five Layers of Protection
UV-C radiation is harmful to eyes and skin. The Void uses redundant hardware safeguards — no software involved in any safety-critical path.
Reed switch in series with UV-C power
Hardware interlockDome removal physically cuts UV-C power. No current can flow without the dome magnet closing the reed switch.
555 timer auto-shutoff (15 min)
Hardware timerUV-C cannot run longer than 15 minutes. The monostable timer enforces this limit in hardware.
3-second button hold required
RC delay circuitAn RC time constant prevents accidental UV-C activation from brief button taps.
Red indicator LED
Visual warningWired in parallel with UV-C power. Lights during the entire sterilization cycle as a visible warning.
Polycarbonate/PETG dome
Radiation enclosureThe dome material blocks 100% of UV-C radiation below 300nm, containing it within the sealed chamber.
HARDWARE INTERLOCK GUARANTEE
The reed switch interlock is wired IN SERIES with UV-C power. This is a hardware guarantee — UV-C physically cannot receive power without the dome seated. Even if timers fail, buttons stick, or any other component malfunctions, the circuit is physically broken when the dome is removed.
Ready to Build?
Download the STL files, source the components, and follow the circuit reference to build your own Void.