OPC UA Server on ESP32

OPC UA server runnning on ESP32 board with a minimal information model to control on-board relays of ESP32-EVB development board from Olimex. Also with a temperature node reading over GPIO 4 from a DHT-22 sensor.

DHT22 Sensor : GPIO 4
RELAY 0      : GPIO 32
RELAY 1      : GPIO 33

It is tested with UAExpert and Matrikon Mobile IOS OPC UA Client. If you see any problems with other clients please open an issue.

Prerequisites

Hardware : Development is based on ESP32-EVB from Olimex but any ESP32 board is expected to work.
ESP-IDF : https://docs.espressif.com/projects/esp-idf/en/latest/get-started/

Getting Started

Blog post with more information: Selftronics

It is required to have ESP-IDF and configured in local.

git clone --recursive https://github.com/espressif/esp-idf.git <your-esp-idf-root-path>
cd <your-esp-idf-root-path>
./install.sh
source export.sh
cd <your-esp-idf-root-path>/examples/
git clone https://github.com/cmbahadir opcua-esp32
cd opcua-esp32
idf.py build

Open62541.c and open62541.h are amalgamated OPC UA C stack files. If you are interested more on the OPC UA stack, please check Open62541 project.

If you want to build open62541.c/.h/.lib from source, be sure to apply the changes in here to make it compatible with FreeRTOS and xtensa-toolchain.

I haven't analyzed these modifications in open62541.c/.h files, these are just a result of trial and error process, but open62541 project is still being developed to make it easier. I would suggest to follow this long but full of practical information thread to overcome the problems about compiling open62541's with FreeRTOS.
OPC UA stack: Open62541

Configuration

Type of connection, Wi-Fi SSID, password and static ip configuration can be set through esp-idf's menuconfig tool. Connection can be configured from under "Connection configuration" on configuration menu run by executing the command:

idf.py menuconfig

License

This project is licensed under the Mozilla Public License Version 2.0 which is inherited from Open62541 project - see the LICENSE.md file for details.

Attention