Greenhouse Controller
A complete wireless greenhouse monitoring system designed exclusively from Circuit Issues templates — no custom power or RF circuits from scratch. This project shows exactly how the catalog templates fit together on a real product.
System photo — coming with build log
System overview
The greenhouse controller monitors soil moisture, air temperature, humidity, and ambient light. All data is exposed over WiFi via ESPHome and visualised in Home Assistant. The board is powered from a USB-C supply or a 1S Li-Ion cell for portable or outdoor deployment.
| MCU | ESP32-S3 (WiFi + BLE) |
| Power input | 5 V USB-C or single-cell Li-Ion |
| Charging | MCP73832, 500 mA |
| Rail supply | TPS62821 3.3 V / 3 A buck |
| Sensors | Soil moisture (ADC), DHT22 (temperature/humidity), light (LDR) |
| Connectivity | WiFi 802.11 b/g/n (ESP32-S3) |
| Firmware | ESPHome / compatible with Arduino |
| PCB | 2-layer, 60 × 45 mm, open-source (KiCad) |
Templates used
Every power, connectivity, and analog subsystem on this board came directly from a Circuit Issues template — zero custom circuit design required for those blocks.
ESP32-S3 Minimal Circuit
Minimal but complete ESP32-S3 circuit with QSPI flash, auto-download, USB-C with ESD protection, and RF layout best practices. Drop-in ready for IoT and wireless products.
Li-Ion Battery Charger (MCP73832)
A compact, single-cell Li-Ion/Li-Po charging circuit based on the Microchip MCP73832. Includes thermal and over-charge protection, status LED, and EU supplier BOM.
3.3 V Buck Converter (TPS62821)
High-efficiency synchronous step-down converter based on TI TPS62821. Delivers 3 A at 3.3 V from 4–17 V input with >90 % efficiency. Layout follows TI reference guidelines.
ADC Frontend with Filtering
Op-amp signal conditioning front-end with anti-aliasing filter and input protection. Designed for interfacing 0–5 V industrial sensors to 3.3 V MCU ADC inputs.
Key integration decisions
Shared 3.3 V rail
The TPS62821 buck converter output feeds both the ESP32-S3 core and the ADC op-amp supply. The ADC template's analog-ground pour is stitched back to the buck's output capacitor via a star point under the ESP32 module.
USB-C dual role: charge + flash
A single USB-C connector handles both Li-Ion charging (via MCP73832) and firmware flashing. A load-switch plus Schottky OR-circuit selects VBUS vs. battery as the input to the buck converter without processor intervention.
ADC reference from LDO
The ADC frontend is powered from the same 3.3 V buck rail, but its VREF pin is driven from a separate 100 mA LDO (LP2985) to isolate switching-supply noise from the reference chain.
Single 2-layer PCB
All four templates were integrated onto a single 60 × 45 mm 2-layer board. The template PCB footprints were used as starting sub-sections and merged, preserving the critical-path constraints documented in each design note.
Build log
4 posts plannedWhy I Built a Greenhouse Controller From Templates
PlanningComing soonThe motivation, system requirements, and why reusing proven building blocks beats designing from scratch every time.
Integrating Four Templates on One PCB
HardwareComing soonCombining the ESP32-S3 core, Li-Ion charger, 3.3 V buck, and ADC front-end: how the planes, connectors, and shared rails fit together.
Board Bring-Up and Sensor Calibration
DebugComing soonFirst power-on checklist, probing the rails, flashing firmware over USB-C, and calibrating the soil-moisture ADC channel.
ESPHome Integration and Home Assistant Dashboard
FirmwareComing soonWriting the ESPHome YAML, mapping GPIO to sensors, and wiring the dashboard for temperature, humidity, and soil moisture.
Video walkthrough
Video coming with build log series
Build your own project from templates
Get the IoT Starter Bundle — the same three templates used in the greenhouse controller, bundled at a 20 % discount.