ESP32 Sensor and Control Schematic
Thought
Work done
- Applied the required explicit per-net trace-width rules: 12V and HEATER_12V_SW at 2.0mm, GND at 1.0mm with Bottom preference, 3V3/5V at 0.8mm, and remaining named signal/control nets at 0.3mm.
- Reconfirmed the PCB is on a 120mm × 100mm, Standard 2-layer stackup.
- Reworked placement once to improve separation and keep the high-current zone on the right; relay/J1/J2 remain intended for the right-side power/heater area.
- Fixed the Layers with Multiple Fills issue by limiting unintended sublayout fill participation; latest review shows that category is now clean.
- ✅ Net-specific trace-width rules applied and verified for the listed power/signal nets.
- ✅ Bottom-layer GND fill conflict improved: Layers with Multiple Fills is now clean.
- ❌ Routing is not complete: latest review still reports 24 airwires.
- ❌ DRC is not clean: latest review still reports 15 overlapping copper errors and 24 airwire errors.
- ❌ Final fabrication-ready state could not be confirmed: not at 0 airwires / 0 DRC errors.
- Continue with the fix-verify loop: resolve the remaining U5/TFT and 46116ccf copper overlaps, then route all nets in phases — high-current 12V/heater first, then 5V/3V3/GND, then SPI/control/sensor signals — and rerun DRC until clean.
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Project Specification
Title
ESP32 Temperature and Heater Controller
Goal
Create a schematic for an ESP32 DevKit based temperature and heater controller powered from a 12V 10A supply. The system reads two DS18B20 temperature sensors, drives a 5V relay module for a 12V heater, displays status on a 2.8 inch ILI9341 SPI TFT, and provides buzzer, LED, and push button user interface.
Architecture
Diagram
Design Assumptions
- Use the ESP32 DevKit VIN/5V input from a regulated 5V rail generated from the 12V supply.
- Use the ESP32 DevKit 3V3 rail for DS18B20 power and OneWire pull-ups to keep sensor data ESP32-safe.
- Use two independent OneWire GPIO nets, one per DS18B20 sensor, each with its own 4.7kΩ pull-up to 3V3.
- Use a 5V relay module input driven by an ESP32 GPIO. Because this is a module, coil driver and flyback protection are assumed to be included on the relay module.
- Relay contacts switch the 12V heater high side through COM and NO.
Planned GPIO Map
Table
| Function | ESP32 GPIO |
|---|---|
| DS18B20 Sensor 1 data | GPIO4 |
| DS18B20 Sensor 2 data | GPIO16 |
| TFT SCLK | GPIO18 |
| TFT MISO | GPIO19 |
| TFT MOSI | GPIO23 |
| TFT CS | GPIO5 |
| TFT DC | GPIO21 |
| TFT RST | GPIO22 |
| Relay control | GPIO25 |
| Active buzzer | GPIO26 |
| Red LED | GPIO27 |
| Push button | GPIO32 |
Power Rails
- 12V: external 12V 10A supply and heater load.
- 5V: buck-regulated logic/module supply for ESP32 VIN, relay module, and TFT module.
- 3V3: ESP32 DevKit regulated output for OneWire sensors and pull-ups.
- GND: shared logic ground for ESP32, sensors, display, relay module input, buzzer, LED, and button.
Title
Goal
Architecture
Design Assumptions
Planned GPIO Map
Power Rails
