A Wattplot is a raised bed whose canopy is a working solar panel. The plants get filtered afternoon shade where they need it most; the panel gets to keep generating on a structure that would have been lumber anyway. The two outputs — tomatoes and kilowatt-hours — come off the same square footage, and the panel doesn't displace the garden, it completes it.
A solar panel and a vegetable bed don't compete for the same square foot. They share it. The panel protects the crop from the worst of the afternoon sun; the crop returns the favor by making the structure a garden instead of an empty frame. The result is more useful output — tomatoes and kilowatt-hours — per square foot than either one alone.
Tomato leaves stop photosynthesizing above ~95°F. A panel canopy gives the crop filtered afternoon shade during the worst hours, when unshaded plants are cooking but the sun is still strong enough to push a real current.
The irrigation solenoid runs off the panel's own battery. Off-grid watering with no extension cord. Soil-moisture sensing decides when to open the valve; a battery floor and a max-on-time watchdog decide when to stop.
A 620 W bifacial in full sun produces more kWh than the bed's pump + solenoid + controller consume. The frame would be lumber either way — the panel is what turns the structure from a planter into a power plant.
Before you build, get a feel for the geometry. The 3D model is parametric — change one number and the whole structure updates. The pin map shows where every wire lands on the controller. The gallery has 30+ renders, simulations, and booth views.
Drag to orbit, scroll to zoom. Three.js. 8 × 3.7 ft bed, 35° tilt, full structural assembly.
three.js · WebGL30+ renders, simulations, and booth views. Build variants, sun sims, wind loads, breadboard diagrams, and the wood evolution.
30+ images · 4 categoriesEvery wire, every pin. Visual diff between the schematic and the firmware. S3-DevKitC-1, 16 MB flash, 8 MB PSRAM.
schematic rev BSix documented builds, from a 3-hour 18×14″ mini to a full-size 8×5 ft bed with a 620 W bifacial panel. Same firmware, same controller, same parametric model.
What a wattplot is, why it works, when to build one.
18 × 14 inch, ~$193, 3–4 hours. The recommended first build.
100 W bifacial, 24″ stroke actuator, 2×2 frame. The original.
Large bifacial on 72″ posts. ASCE 7-22 wind, 35° max tilt.
Standard residential panel, scaled to 8 × 5 ft bed.
Reuse a decommissioned rooftop panel. $300 less than new.
What to do with broken or underperforming panels.
Every wire, every component, every bolt. The full design is open — schematic, PCB layout, BOM, and pin map.
The brain: ESPHome firmware on an ESP32-S3. PI control on motor current, sun + weather-aware folding, MQTT logging, Home Assistant native integration.
State machine + PI loop. Why current-based homing beats limit switches.
Auto-irrigation with soil moisture + battery floor + max-on-time watchdog.
MQTT log streaming to a rotating file on your PC. 7-day retention.
Pre-power, post-power, and field validation. Bench, wind, water.
Materials for showing the project at a maker faire, science fair, or community workshop.
Single-page summary. Hand it out at a booth.
20 most-asked questions, with answers. For booth volunteers.
How a wattplot fits into a real garden, school, or community plot.
5-minute walk-through for booth visitors.
Run a year of wattplots in 60 seconds. Sun, wind, water, all simulated.
Marquee view, optimized for a 4K booth display. Spinning auto-rotate.
Wattplot