Introducing: ayatec sensoraya PCB v2.1 – The User Guide

To unlock the full potential of the ESP32-S3, we developed the next generation of our programmable I/O boards. The ayatec sensoraya v2 bridges the gap between silicon and the physical world by significantly expanding the already powerful ESP32-S3‘s native I/O capabilities. This allows the sensoraya v2 to serve as a robust foundation for everything from smart-home nodes to specialized industrial automation systems.

Our hardware and software are built for deep customization. This synergy allows developers to scale effortlessly from simple, compact logic to complex, high-reliability embedded applications.

The sensoraya v2.1 represents a significant architectural leap over its ESP8266-based predecessors. Built around the powerful ESP32-S3-WROOM-1U, the new revision integrates a W5500 Ethernet module and external antenna connector for high-reliability networking, built-in optocouplers for robust industrial interfacing, or an on-board USB-C port for easy communication with the chip.

We have eliminated previous hardware trade-offs to provide maximum variability while retaining the classic Hammond enclosure, refined with a more contemporary aesthetic. The result is a professional-grade controller ready for a wide range of applications, including:

2. PCB Sizes

The sensoraya features a segmented PCB design (Segments A, B, and C), allowing the board to be scaled physically based on the project’s I/O requirements. As the core segment A is fully autonomous, segments B and C can be removed to create three distinct size variants.

The I/O diagrams and descriptions provided in the following sections relate to the maximum configuration of the sensoraya PCB.

For the comprehensive listing of hardware capabilities of all the size variants you may check the following overview (sizes expressed in standard DIN modules):

Mini variant
(4-module)

The board’s core contains the ESP32-S3 microcontroller with the 7-30V VIN adapter and:

• 2 Relays
• 4 Power MOSFETs
• 5 Direct GPIO digital inputs
• I2C dedicated display connector
• DFPlayer MP3 module
• RTC module
• W5500 Ethernet module
• WiFi Antenna connector (integrated within the chip)

Mini variant is the smallest option (only 7 cm wide), best for compact applications requiring only a limited number of inputs and outputs.

Medium variant
(6-module)

Contains all options from the Mini variant with the addition of:

• 2 Relays
• 5 Optocoupler inputs
• 4 Power MOSFETs
• On-board Buzzer

Medium variant is the middle option (10,5 cm wide), providing additional inputs and outputs and representing the “sweet spot” for many automation projects.

Maxi variant
(9-module)

Contains all options from the Medium variant with the addition of:

• 6 Relays
• 8 Analog inputs

Maxi variant is the most powerful and largest option (16 cm wide). Designed for complex industrial logic or full-scale automation hubs requiring extensive sensing options and high relay counts.

The board transforms the ESP32-S3‘s native processing power into a following I/O array:

Output capabilities:

• 10 relays (4x 8A @ 250V AC (Changeover/SPDT) + 6x 5A @ 250V AC (Standard/SPST))
• 8 power MOSFETs (max 2.5A per channel @ 30V DC without external cooling)
• Audio/Visual: Buzzer and a dedicated MP3 module (DFPlayer) for alerts, sound effects, or music

Input & Connectivity:

• 5 optocoupler inputs
• 8 analog inputs (10kΩ)
• 5 direct GPIO digital/touch/analog multipurpose pins (ideal for digital peripherals like DS18B20, 1838 IR, HC-SR04, and other)
• Communication: W5500 Ethernet port, WiFi antenna, I2C dedicated connector (primarily intended for display), RTC module

The board requires a power supply of 7-30V DC via a dedicated connector in the upper-left corner of the board. Make sure that your power supply is capable of providing at least 10W.

4. Relay Outputs

As the most basic output, the sensoraya PCB features up to 10 medium-load power relays of the following two types:

• Standard/SPST relay with maximum load of 5A @ 230V (up to 6 units in total, 2 units located on each of the segments A, B, and C)
• Changeover/SPDT relay with maximum load of 8A @ 230V (up to 4 units in total, all located on segment C)

The on-board relays can only be accessed in combination with the board’s built-in 74HC595 Shift Register and its output pins RE1 – RE10 (please refer to the schematic for more details).

Each relay has a dedicated on-board indicator LED showing the current output state of the respective relay.

Connectors J9 – J14 and J16 are dedicated to the power relays. Standard two-terminal relays share the 4-pin connectors in pairs, while each three-terminal changeover relay has its own 3-pin connector.

Check out the Demo sketches below to try out the Shift Register functionality.

5. Analog Inputs

As the basic analog and logical inputs, the sensoraya PCB carries up to 8 analog pins I1 – I8. While the I8 is reserved for the on-board 10kΩ NTC Thermistor, I1 – I7 are fully available for general use.

These analog inputs can only be accessed via dedicated J8 connector. These are managed by the board’s built-in Shift Register and Analog Multiplexer. Each of these inputs is configured with a 10kΩ voltage divider (pull-up). This internal biasing makes them ideal for direct connection to resistance-based sensors like NTCs, LDRs, or potentiometers (in contrast to the D1 – D5 inputs, which are the ‘raw’ GPIOs, designed to read 0–3.3V analog signals directly without additional divider).

Please note that I1 – I8 inputs are relatively slow, with only a limited number of samples per second due to the multiplexer switching. It is therefore not recommended to use them to read narrow impulses, which can be easily overlooked.

Check out the Demo sketches below to try out the Shift Register & Analog Multiplexer functionalities.

New to the sensoraya v2 are five optocoupler inputs, providing a critical layer of protection for the ESP32-S3. These inputs are galvanically isolated from the primary logic circuit, making them the ideal choice for:

• Long-distance signaling where ground potential differences might occur.
• High-noise industrial environments (e.g., near motors or high-voltage switchgear).
• Interfacing with different voltage domains without risking back-feeding the MCU.

All five optocoupler channels are grouped on a single dedicated J6 connector with a shared common ground.

For the optocoupler hardware we chose the EL357 for its high isolation voltage (3,750V_RMS) and reliable performance in SOP4 packaging. With a typical response time of 18μs, these inputs are perfectly suited for industrial sensors and PLC signal integration up to ~20 kHz.

For high-speed switching and dimming, the sensoraya v2 features 4 or 8 independent AO3400A N-Channel MOSFETs. These support both high-frequency PWM (for LED strips) and standard digital switching (for DC motors or contactors). They can also be used as simple logical output to switch compatible external relays or contactors. They can be accessed via the 5-pin connectors J17 and J15, located on segments A and B, respectively.

Flexible Power Routing (J15 & J17)

The power delivery for these MOSFETs is highly configurable via onboard solder jumpers. Each 5-pin connector features a common supply pin that can be set to one of two modes:

• Shared Power (VIN Mode): If the VIN jumper is connected, the board’s own power supply (7-30V) is routed to the output. This simplifies wiring for low-power components. Ensure your power supply can handle the combined load of the board and all attached peripherals.
• Isolated Power (GND Mode): If the GND jumper is connected, the pin acts as a ground bridge to an external power supply. This allows the MOSFETs to switch loads at a different voltage than the board logic, providing electrical protection for the board’s core power rail.

DANGER OF SHORT CIRCUIT: Never bridge the VIN and GND jumpers for a single connector simultaneously. Doing so will create a direct short across your power supply and may cause permanent damage to the PCB and/or connected electrical components.

Each of the remaining 4 pins on either of the connectors represents one individual MOSFET. Check the table below or the official schematic for exact wiring and positioning of each individual MOSFET output:

Connector	Position	Name	GPIO reference
J17 (Seg. A)	1	VIN/GND	–
	2-5	P1-P4	15, 16, 17, 18
J15 (Seg. B)	1	VIN/GND	–
	2-5	P5-P8	19, 20, 3, 46

Each MOSFET has a dedicated indicator LED showing the current output state of the respective MOSFET.

RGB Driver

The board can operate as a full-fledged LED strip driver for 2 independent RGBW modules, fully supported by unicontrol.

Check out the basics of working with unicontrol RGB Driver in the dedicated article.

When high-speed communication or specific protocols (like OneWire, Pulse Counter, or Bit-banging) or high-speed analog or touch readings are required, the sensoraya v2 provides direct access to the selected ESP32-S3‘s native GPIO pins.

While these connectors provide 5V to power your sensors, the ESP32-S3 logic is strictly 3.3V. To simplify interfacing with 5V sensors (like certain ultrasonic distance sensors or industrial encoders), we have integrated on-board voltage dividers. If your sensor returns a 5V signal, you can safely step it down by bridging the JP3, JP4, or JP5 solder jumpers. Without the jumpers bridged, the pins act as standard 3.3V I/O. Always verify your sensor’s output voltage and consult the official schematic before bridging these jumpers to ensure correct attenuation.

These are distributed across three dedicated connectors as per the schematic or the following diagram.

The sensoraya v2.1 accommodates an MLT-8530 passive buzzer connected to the IO14 pin of the ESP32S3.

While the sensoraya v2 is compatible with any ESP32-S3 firmware (such as ESPHome, Tasmota, or MicroPython), it is designed to be the flagship hardware for unicontrol. This native firmware is specifically optimized to handle the board’s shift-register architecture and I/O multiplexing out of the box, maximizing the hardware’s efficiency.

For developers who prefer custom logic, the board functions like any standard ESP32-S3 development module. You can compile and upload your own code using the Arduino IDE, ESP-IDF, or PlatformIO.

The board features a built-in USB-C port connected to an on-board Serial-to-TTL translator (CH340C). This ensures a stable connection for high-speed flashing and serial monitoring across all operating systems without needing external programmers.

To assist you in developing your own firmware for the sensoraya v2.1, we have prepared a GitHub repository with basic definitions and an extensive set of example sketches for Arduino IDE that demonstrate all of the board’s capabilities.

Get started:

1. Install Arduino IDE with the ESP32 boards package
2. Install AyatecSensoraya2.x library via the Library Manager
3. Connect the board to your PC via a USB-C cable.
4. Choose ESP32S3 Dev Module as the board
5. Open File → Examples → AyatecSensoraya2.x → 01_Basics → 01_Blink
6. Click Upload

Visit our GitHub repository

To continue your journey with us, you may want to check out our online knowledge base. It will help you get on board as quickly as possible, shortening the road to your goals. It ranges from technical details explained in the user guide to real-time, step-by-step demonstrations found in our video tutorials.