One real greenhouse · three ESP32s · zero excuses

A backyard greenhouse that runs itself.

Roof windows that open with the heat and slam shut before a storm. Watering by relay. A daily AI read on what the plants went through. Built at home, wired by hand, documented honestly — bugs included.

status
● alive & venting
Live from the dashboard

The greenhouse, as the software sees it.

The real dashboard shows this scene in realtime over MQTT: two roof flaps that actually move, a climate map, and — since this week — a water-zone glow that honestly covers only the north bed, because that's the only bed valve 1 reaches.

inside temp
–°C
humidity
–%
roof state
▲ simulated preview — the real thing runs on MQTT + SSE
north flap south flap north bed — valve 1 zone south bed mqtt
Every night at 00:00

An AI agronomist reads the day back to you.

Once a day the server sends 24 hours of temperature, humidity and cloud-cover history to Claude, which returns a short plain-language analysis: how the climate behaved, and early warnings for heat stress or mildew risk. It shows up on the dashboard like a note from someone who was watching all day.

daily-analysis · claude
mildew watch

“A warm afternoon peaking at 27.4°C; the roof vented on time and kept the spike short. Overnight humidity stayed above 85% under cloud cover — watch the lower tomato leaves for early mildew, and consider venting earlier tomorrow morning.”

generated from 24h of sensor history — no prompts, no dashboards to read
The system

Three small computers, one stubborn builder.

Every node is a €5 ESP32 talking MQTT to a small server. Fail-safe by design: lose the network and the windows close, valves shut themselves off, nothing floods.

esp32 ×2 · roof
01
Self-venting roof windows

Two nodes drive 12V linear actuators through BTS7960 H-bridges — one per roof flap, north and south. A weather guard on Open-Meteo data closes both windows on thunderstorms, gusts over 50 km/h or rain, then restores the last wanted position when it clears.

failsafe: heartbeat lost 2h → windows close
esp32 · sensors + engine
02
Climate engine + nightly AI

A sensor node publishes inside temperature and humidity over MQTT. The climate engine vents on hysteresis — open above 25°C, close under 21°C — with the weather guard always taking priority. At midnight, Claude analyses the full day.

weather override beats everything
esp32 · water
03
Relay-driven watering

A fail-safe-closed 1″ solenoid valve on a Grove relay, on its own node with its own firmware — deliberately decoupled from the climate logic. Manual for now, from a dashboard button or a shell script; soil-moisture automation is the next chapter.

failsafe: 4h auto-timeout per valve
honest footnote

The roof limit switches are probably dead or miswired, so the move-timeout is parked at 90 seconds as a workaround. The DS18B20 outdoor sensors never worked despite hours of diagnosis; a DHT11 does the job for now. That's what building real hardware looks like — and it all still runs.

Build log

Built in phases, in the open.

PHASE 1
running
Roof windows, north + south

Actuators mounted, H-bridges wired, limit switches fitted (and promptly suspected dead — 90s timeout workaround in place). The weather safety-close and the 2-hour heartbeat failsafe have both already earned their keep.

PHASE 1.5
running
The sensor node

A separate ESP32 with a DHT11 for inside temperature and humidity, publishing WiFi signal strength as a bonus. The fancy DS18B20 probes never talked back despite extensive diagnosis — the humble onboard sensor won.

PHASE 2
running
Climate engine + AI analysis

climateControl.ts vents automatically on inside temperature with clean hysteresis. And once a day, the last 24 hours of climate history goes to Claude for a short written analysis with heat-stress and mildew warnings.

PHASE 3
just started · aug 2026
Watering

Firmware flashed and tested over USB; the relay clicks on command. Confirmed this week: valve 1 only waters the north bed — so the dashboard now honestly shows the water glow on the north plants only. Next up: wiring the 12/24V supply to prove the valve really opens.

Where this goes next

This started as one greenhouse. It doesn't have to end there.

If enough people want it, two things could exist. Tell me which one you'd use — that's genuinely what decides the roadmap.

concept 01
The Kit

Pre-flashed ESP32 nodes, actuator drivers, relay board and wiring guide — retrofit any hobby greenhouse with self-venting windows and watering in a weekend. No soldering marathon, no firmware rabbit hole.

I'd buy the kit →
concept 02
The Software

The dashboard and climate engine as a product: live scene of your greenhouse, weather-aware failsafes, and the nightly AI analysis — for growers who already have the hardware but not the picture.

I'd use the software →
concept 03
The Training

Learn to build it yourself: a hands-on course from the real build log — wiring ESP32s and actuators, MQTT, fail-safe design, and hooking up the AI analysis. As a video series, workshop or a day in the actual greenhouse.

Teach me →