Basic I/O

The unicontrol lets you take advantage of a wide variety of hardware configurations with an ESP32-S3 or ESP8266 MCU at the core.

Compatible boards

In essence, the unicontrol software is compatible with any ESP8266ESP32-S3 chip with Flash memory of 4MB or more. This software has been tested and verified on multiple boards as follows (not exhaustive):

The unicontrol is capable of controlling the full hardware capabilities on any ESP8266ESP32-S3 - based development boards, applying individual boards' limitations. In the basic configuration, you may directly control the following I/O:

Please check the Peripheral page to find out more about hardware setup possibilities.

Basic I/O

Following the listings above, in the most basic scenario you may use the available on-board GPIOs as:

• Plain digital output,
• Plain digital input, and
• Analog input.

Plain digital (logical) output

The first and most obvious capability of unicontrol is connecting a basic HIGH / LOW-output type device to the ESP8266 board and control it via turning a GPIO pin on and off according to a pre-set timer, external command or any measurable event. With a minimum set-up (using a relay, mosfet or nothing at all) you may for example:

• open or close a house gate or garage door,
• turn any light (including LED) on and off,
• dim an LED/LED stripe, or
• switch a fan, water pump, or any other 100/230V device on and off.

Plain digital (logical) input

All ESP8266 GPIO pins are capable of reading a basic HIGH/LOW-input type signal and using this information either to control an output or post it online. With a minimum setup (using a resistor or nothing at all), you may, for example, read the logical state of:

• PIR movement sensor,
• capacitive touch sensor,
• shock or sound sensor,
• mechanical switch or a button, or any other low voltage HIGH/LOW-based input.

Analog input

The A0 pin holds a special place among the ESP8266 capabilities as its built-in A-D converter allows it to measure not only a HIGH or LOW state, but also a full range of input voltage from 0 to 3.3. By connecting a suitable sensor to the A0 pin in a correctly chosen voltage divider configuration, you can measure:

• potentiometer,
• water level in a flower pot,
• light brightness,
• soil moisture,
• temperature, or
• any other analog input measurable with a resistance-based sensor.

System Button

The System button is a pre-programmed ESP8266 GPIO button functionality, which serves exclusively for the most basic system commands, depending on how long it is pressed:

• Short press (shorter than a second with display in screensaver mode): Temporarily disables the screensaver mode.
Screensaver mode was introduced in version 1.16. In this mode, the display only renders alerts but is dimmed otherwise to prevent its excessive wear resulting in loss of brightness or burn-in. The screensaver mode is initiated automatically after 5 minutes of uninterrupted operation, but only if the Display is in use and the System Button is assigned to I1 or I8. This timer resets with each press of the System Button. Starting with version 1.17, the display in screensaver mode continues to show status information by briefly flashing a single, double, or triple status dot every 10 seconds, corresponding to one, two, or three flashes of the status LED, respectively.
• Short press (shorter than a second without display in screensaver mode): Toggles between the Wi-Fi modes Station, Access point, and Off.
Starting with version 1.17, the Wi-Fi mode automatically reverts to its default mode after 5 minutes.
• Medium press (between 1 second and 10 seconds): Reboots the device.
• Long press (longer than 10 seconds): Performs a factory reset of the device, replacing ALL settings with the factory defaults and reboots the device.

By default, the System Button is assigned to the I8 analog input, only accessible with the Analog multiplexer. However, users can change this to any digital pin from D1 to D7, or the I1 or I8 pins of the Analog multiplexer, or even disable the button entirely.

Using the System button on any ESP8266 board other than NodeMCU* will require adding the designated hardware button first. To do so, connect the System button pin (D4 by default) to one leg of the button, and the GND pin to the other as per the schematic below:

System LED

The System LED is a pre-programmed ESP8266 on-board LED functionality, which serves exclusively for the most basic system diagnostics. The information provided by the device can be inferred from the LED sequence as per the table below:

LED Sequence		Interpretation
	LED is on (for up to 10 minutes)	The device is booting and, if requested, resetting to factory defaults.
	10 fast flashes over the course of 2 seconds	The device has booted succesfully.
	1 short flash every 10 seconds	The device is running without an active STA Wi-Fi connection.
	2 short flashes every 10 seconds	The device is running and has successfully connected to Wi-Fi (STA).
	3 short flashes every 10 seconds	The device is running and has successfully connected to both Wi-Fi (STA) and MQTT broker.
	1 long flash every 10 seconds	The device is running in the Wi-Fi AP mode or has just been switched to this mode by short-pressing the System button.
	1 very long flash every 10 seconds	The Wi-Fi is off.
	Rapid flashing over the course of 2 seconds	Reboot and reset to factory defaults is following.
	4 rapid flashes every second	The System button is pressed and held.

By default, the System LED is assigned to the D4 pin on the ESP8266 board. However, users have the option to change this assignment to any digital pin from D0 to D8 or even disable the System LED entirely if not required.