Smart-home automation and industrial control are increasingly coming together. Developers want the flexibility of ESP32 microcontrollers, the convenience of wireless connectivity, and the ability to control real-world equipment through platforms such as Home Assistant.

The Eletechsup ES30F27 is an ESP32 expansion board designed for exactly this kind of experimentation. With eight optically isolated digital inputs, eight relay outputs, RS485 communication, and additional I/O interfaces, it provides a practical hardware foundation for custom automation projects.

An independent user has shared progress integrating the ES30F27 with ESPHome and Home Assistant, offering a useful example of how the board can be explored beyond traditional standalone relay control.

1. ESP32 Hardware with Eight Inputs and Eight Relay Outputs

The ES30F27 combines multiple control interfaces on a single expansion board.

Key hardware features include:

• 8 optically isolated digital inputs with low-level triggering and NPN-type input configuration.

• 8 relay outputs with specified 10A relay contacts, subject to the applicable load and electrical ratings.

• RS485 interface for serial communication with compatible equipment.

• I2C and SPI interfaces for connecting supported peripheral devices.

• 7 ADC channels exposed for compatible analog-input applications.

• Wi-Fi connectivity, provided by a compatible ESP32 development board.

• DIN-rail enclosure for installation in suitable control cabinets.

The board is available in 12V DC and 24V DC versions.

One important detail is that the ES30F27 is an expansion board, not a complete standalone controller. A compatible 30-pin ESP32 development board must be installed separately, and the required firmware must be developed or configured.

2. Exploring ESPHome and Home Assistant Integration

Home Assistant is widely used for managing smart-home devices, while ESPHome allows compatible microcontrollers to be configured through YAML and integrated with Home Assistant.

An independent ES30F27 user published a practical integration discussion on Eletechsup's FAQ page:

Reference: https://eletechsup.com/blogs/news/es30f27-faq

The user shared an ESPHome configuration that successfully controlled the board's LED through a Home Assistant interface. The user also reported progress with the relay outputs, including activation of their indicator LEDs, while continuing to work on the remaining functions.

The discussion highlights an important opportunity: developers who want to use the ES30F27 with Home Assistant benefit from clear GPIO mappings, working YAML examples, and tested configurations.

The shared configuration is an early integration example rather than a complete, verified configuration for every input, output, and communication interface.

3. Remote Switching and Custom Automation

Once the ESP32 firmware and control logic have been configured, the ES30F27 can serve as a hardware platform for custom switching applications.

Potential projects include:

Lighting and electrical switching

Control compatible lighting circuits and other electrical loads through relay outputs, using appropriate wiring, protection, and load ratings.

Sensor-triggered automation

Read compatible digital input signals and activate outputs according to programmed conditions.

Timed switching

Implement scheduled switching, start-up delays, trigger delays, and repeated sequences in firmware.

Equipment control

Build custom interfaces for fans, pumps, valves, and other suitable equipment. Motor direction control requires a correctly designed external circuit and suitable interlocking logic.

These are development possibilities, not functions automatically enabled by installing the board. The final behavior depends on the ESP32 firmware, the chosen automation platform, and the electrical design.

4. RS485, I2C, and SPI for More Flexible Projects

The ES30F27 is not limited to Wi-Fi-based smart-home control.

Its RS485 interface can support communication with compatible serial devices. With suitable firmware, developers can investigate Modbus RTU or other serial protocols.

The exposed I2C and SPI interfaces provide additional options for peripheral integration, while the ADC channels can be used for compatible analog signals within their specified electrical ranges.

This combination is useful for projects that need both local physical I/O and communication with external devices.

However, these interfaces require correct pin assignments and software implementation. Eletechsup supplies basic Arduino code for hardware testing, but custom ESPHome, MQTT, HTTP, or Modbus integrations may require additional development.

5. Why Ready-to-Use Examples Matter

The ES30F27 community discussion reveals a common challenge with programmable hardware: a capable board is only part of the solution.

Users also need to know which ESP32 pins control the relays, how the input circuitry is read, and how the hardware should be represented in ESPHome.

Providing verified examples could make the board easier to evaluate and integrate. Useful documentation would include:

• A minimal ESPHome configuration for the board's status LED.

• Tested configurations for individual relay channels.

• Input-reading examples for the eight optically isolated inputs.

• A complete GPIO mapping and wiring reference.

• RS485 communication examples.

• Troubleshooting notes for power supply selection and ESP32 compatibility.

These are recommended documentation improvements, not a claim that all these examples are currently available.

6. A Practical Platform for DIY and Embedded Developers

The ES30F27 is relevant to developers who want to combine ESP32 programmability with physical I/O in a compact, DIN-rail-mountable format.

Its eight relay outputs and eight isolated inputs make it suitable for experiments involving switching, sensor monitoring, and custom automation. Its additional communication interfaces also provide room for more advanced projects.

The independent ESPHome and Home Assistant discussion demonstrates real user interest in integrating the board with an established automation ecosystem. It also shows why tested examples and clear technical documentation can make a meaningful difference to the developer experience.

For engineers and makers who enjoy building their own control logic, the ES30F27 offers a flexible starting point for exploring ESP32-based automation.

Explore the Eletechsup ES30F27

• Product page: https://eletechsup.com/products/es30f27-simple-plc-development-board-based-on-esp32-es30f27-wifi-expansion-board-for-rs485-i2c-spi-bus-development

• ESPHome and Home Assistant integration discussion: https://eletechsup.com/blogs/news/es30f27-faq

The ES30F27 requires a compatible 30-pin ESP32 development board and user-configured firmware. Third-party ESPHome configurations are independently developed and may require adaptation. Always verify pin mappings, input behavior, relay ratings, and wiring before connecting real equipment.