Smart Home Gateway with PHPOC Black

Part 2: Integrating Additional Sensors and Actuators

- By Raul Alvarez-Torrico

The PHP on Chip "Black," is a programmable IoT microcontroller board used to develop a prototype for a smart home gateway. In the second part of this two-part series, Raul enhances the base system by integrating light intensity and air quality sensors, along with two relays to control ambient lighting and an air ventilation fan. He also explores methods to connect remote nodes to the smart home gateway via Wi-Fi, expanding its control and monitoring capabilities.

In Part 1 of this article series (Circuit Cellar # 420, July, 2025) [1], we introduced the "PHP-on-Chip" (PHPOC) platform by implementing a simple temperature and relative humidity server, using the PHPOC "Black" board. The example provided handson experience configuring an external sensor with the board to obtain sensor readings, and setting up a web and WebSocket server to display those sensor readings on a monitoring webpage.

We examined with reasonable detail the HTML and JavaScript code served by the PHPOC board, which drives the webpage's dynamic content. We also examined the PHP code executing on the PHPOC board that reads the I2C AHT10 sensor and transmits the data periodically, using the WebSocket protocol to the web browser. With this straightforward example, we saw firsthand how the PHPOC platform seamlessly integrates embedded systems with web technologies, offering a highly adaptable IoT solution.

In Part 2 of this series, we will complete the development of this PHPOC-based smart home gateway by incorporating an I2C light intensity sensor, an analog air quality sensor, and two relays to control ambient lighting and an air ventilation fan. We will also briefly explore how remote nodes can connect to the smart home gateway via Wi-Fi to enhance its control and monitoring capabilities.