Petar Marinov

Electronics and Automation eng.

This PLC is built around the ESP8266-12F controller. I chose this controller because it offers good Wi-Fi range, operates reliably, and features low power consumption:

At a 12V supply voltage:

approximately 10 mA with Wi-Fi disabled;

approximately 18–25 mA with Wi-Fi connected to a router.

It includes two inputs, galvanically isolated via optocouplers, and two transistor outputs (rated at 1A each) with a shared 1.5A protection limit. Direct GPIO pins are accessible on both sides of the controller; additionally, dedicated terminals with logic-level converters are provided for I2C, Rx, and Tx, allowing for compatibility with 5V devices. Power can be supplied via a 5V USB-C connector or through a dedicated power jack (supporting 6V to 45V DC). A switching regulator (LGS5145) is used to generate the 5V rail (up to 1A), while a linear regulator (ME6211) steps down the voltage from 5V to 3.3V (with a maximum current of 600 mA).

Versions are available either without a display or with a 0.96″ SSD1306 OLED display.

The controller is compatible with expansion modules, such as the INA219 current/voltage sensor.

SCHEME

GALERY