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ESP32MicroPLC – Component

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The HOMEMASTER MicroPLC is a compact and powerful open-source automation controller based on the ESP32-WROOM-32U. Designed for seamless integration with Home Assistant using ESPHome, it enables control of smart home devices, sensors, actuators, and industrial systems through RS-485 Modbus and wireless communication.
110.00 110.00

Key Features

  • ESP32-WROOM-32U microcontroller with Wi-Fi and Bluetooth

  • ESPHome compatible firmware for seamless Home Assistant integration

  • RS-485 Modbus RTU interface for extension module communication

  • USB Type-C port for programming, debugging, and power

  • 1-Wire interface with ESD and overvoltage protection

  • PCF8563 RTC for accurate time-based automation

  • One industrial-grade relay with varistor and opto-isolation

  • One 24V digital input with surge protection (ISO1212)

  • Front-panel button and status LEDs for local control and diagnostics

  • DIN-rail mountable for standard electrical enclosures

Quick Setup Process

  1. Mount & Power – Install on 35mm DIN rail and connect 24V DC power or use USB-C.

  2. Connect to Network – Use Wi-Fi via Improv (BLE or Serial) for initial setup.

  3. Configure via ESPHome – Access device via Home Assistant ESPHome dashboard.

  4. Wire I/O – Connect sensors and relay loads as needed.

  5. Integrate with Home Assistant – Automations and dashboards ready in minutes.

Technical Specifications

SpecificationDetails
MicrocontrollerESP32-WROOM-32U (Dual-core)
Operating Voltage24V DC or 5V via USB-C
Digital Input1 (24V compatible, ISO1212 protected)
Relay Output1 (SPDT, 16A @ 250V AC, optically isolated)
CommunicationWi-Fi, Bluetooth, RS-485 (Modbus RTU)
RTCPCF8563 with battery backup
1-Wire Interface1 channel with ESD/overvoltage protection
USBUSB-C for configuration and programming
Buttons1 front-panel buttons
LEDsStatus and user-configurable LEDs
Dimensions (W×H×D)Compact DIN rail form factor
Mounting35mm DIN rail

Documentation & Resources

Hardware Design Files
FileDescriptionLink
SchematicComplete circuit schematicSchematic.pdf
System Block DiagramOverall system architecturediagram.png
Pinout DiagramGPIO and connector pin assignmentspinout.png
Product ImageMechanical dimensions and appearanceMicroPLC.png
Firmware & Software
ResourceDescriptionLink
Default ESPHome ConfigPre-configured YAML for Home Assistantmicroplc.yaml
Firmware Source CodeLatest firmware builds and sourceFirmware/
ESPHome Integration GuideComplete setup instructionsREADME.md


Programming & Development

The MicroPLC comes with ESPHome pre-installed and supports multiple development environments:

Configuration Methods:

  1. Improv Wi-Fi Setup – Visit improv-wifi.com and connect via USB or BLE

  2. ESPHome Dashboard – Automatic discovery and one-click import

  3. USB-C Flashing – Direct firmware upload via ESPHome, Arduino IDE, or PlatformIO

Flashing via USB-C:

  1. Connect USB-C cable – automatic reset enabled, no boot button needed

  2. Upload firmware via Arduino IDE, PlatformIO, or ESPHome Dashboard

  3. Device reboots automatically after programming