Overview

Havaxer™ 02 is a multiple-inputs-and-outputs-of-different-kinds controller board (PCB) that allows various functions.

It is based on a popular ESP32-C6 MCU that easily enables IoT via some built-in network connectivity (including Wi-Fi).

02 can be optionally fitted with an OLED. It has built-in two buttons (+ reset), an eBUS adapter wired via an UART interface and an additional twin IO.

It was originally designed to control a complete HVAC system with two heating/cooling circuits. The built-in network connectivity enables data to be sent to a remote location for monitoring and controls to be received by the remote interface, for example.

The MCU comes pre-programmed with my example application for demonstration and testing purposes only. Otherwise you have to write your own application and program the MCU by yourself.

There is no safety enclosure for the board and thus no physical protection, yet. You can install it in other enclosure, be it provisional or electrical, or inside other device, like a heat pump. You can also hang it on the wall and just be very careful around it.

Status

Version 1.0

In PCB diagram PDF you can find a complete and very transparent layout of the PCB, which, when printed on a paper, gets you a precise size and dimensions, too.

Next is a rendered 2D PCB with all components, except the missing MCU. Note that colors might not be correct.

Next is a rendered 3D PCB with all components, except the missing MCU. Note that colors might not be correct.

Specifications

The board is an industrial/consumer electronics manufactured PCB:

• FR-4, lead-free, green
• 4 layers, 1.6 mm thick
• 195 mm x 160 mm
• height approx. 20 mm
• weight approx. 212 g

The MCU is the Espressif ESP32-C6-WROOM-1 N8 model and provides:

• 32-bit RISC-V architecture
• 1-core CPU with max 160 MHz
• 8 MB flash
• 2.4 GHz Wi-Fi 6 with an on-board PCB antenna
• Bluetooth 5 (LE)
• Zigbee & Thread

Connections:

• TIO header (twin general purpose input/output, 3.3 V)
• UART header (3.3 V)
• eBUS adapter (24 V) to UART
• I2C display header (3.3 V)
• I2C QWIIC connector
• USB-C connector (programming, debugging and power)
• alternative power supply terminal (7-33 V)

Inputs:

• 6x analog temperature sensor (NTC 10k)
• 2x mains optocoupler (250 VAC)

All inputs are multiplexed to one MCU pin, so only one programmatically selected input can be read at once.

Outputs:

• 4x mechanical relay (250 VAC, 10 A), one shared with TIO
• 4x solid state relay - triac (220 VAC, 1.2 A)
• 2x driver (5 VDC, 100 mA), one shared with TIO

All outputs are wired via additional hardware gates that need to be opened programmatically.

Pricing, Order

Prior shipping, each board is inspected, programmed and tested. If optional items are ordered, they are also inspected, tested and attached to the board.

VAT is included.

Shipping is possible only inside the European Union.

Statements

Terms of Sale & Buyer Eligibility

1. Restricted to Professional & Technical Users

This product is intended exclusively for professional users, businesses, or technically skilled individuals with sufficient expertise in electronics. It is not intended for general consumer use.

2. Compliance and Certification Notice

By purchasing this product, you acknowledge and agree that this item:

• Does not comply with standard consumer product regulations.
• Is not certified by regulatory bodies (e.g., it lacks CE, FCC, or UL markings).
• Requires advanced knowledge, assembly, integration, testing, and the implementation of appropriate safety measures by the buyer.

3. Buyer Responsibility

Buyers acknowledge that they possess the necessary technical knowledge to safely use, evaluate, and integrate the product. You accept full responsibility for verifying its suitability and ensuring compliance for your intended setup.

Liability Disclaimer & Safety Warning

⚠️ WARNING: HIGH VOLTAGE RISK

This product is designed to connect to and control high-voltage mains electricity via its onboard components. Mains electricity can cause severe personal injury, permanent disability, electrocution, fatal electrical shock, or property fire if handled incorrectly.

1. "As-Is" Status & No Warranties

This product is provided strictly on an "as-is" basis. The Seller makes no warranties, express or implied, regarding its safety, reliability, or fitness for any particular high-voltage application.

2. Absolute Assumption of Risk

By handling, installing, or interfacing this product with mains voltage, you assume all inherent risks. You are entirely responsible for implementing physical enclosures, proper insulation, fusing, and grounding to ensure safe operation.

3. Complete Exclusion of Liability

In no event shall the Seller be held liable for any direct, indirect, incidental, or consequential damages. This includes, but is not limited to, bodily injury, death, property damage, loss of home, or equipment failure resulting from the connection, use, misuse, or failure of this product.

4. Maximum Remedy

The Seller's total liability for any claims or damages arising from this purchase shall not exceed the actual purchase price paid for the product.

Examples

This theoretical example shows what the Havaxer 02 was designed for.