This project was started from [this](https://www.mikrocontroller.net/topic/525778) discussion (Mikrocontroller.net).
It was the goal to replace the original Hoymiles DTU (Telemetry Gateway) with their cloud access. With a lot of reverse engineering the Hoymiles protocol was decrypted and analyzed.
Compatibility with OpenDTU seems to be related to serial numbers. Current findings indicate that TSUN inverters with a serial number starting with "11" are supported, whereby inverters with a serial number starting with "10" are not.
Firmware version seems to play not a significant role and cannot be read from the stickers. For completeness, the following firmware version have been reported to work with OpenDTU:
* Uses a fork of [ESPAsyncWebserver](https://github.com/yubox-node-org/ESPAsyncWebServer) and [espMqttClient](https://github.com/bertmelis/espMqttClient)
For ease of use, buy a "ESP32 DEVKIT DOIT" or "ESP32 NodeMCU Development Board" with an ESP32-S3 or ESP-WROOM-32 chipset on it.
Sample Picture:
Also supported: Board with Ethernet-Connector and Power-over-Ethernet [Olimex ESP32-POE](https://www.olimex.com/Products/IoT/ESP32/ESP32-POE/open-source-hardware)
The PLUS sign is IMPORTANT! There are different variants available, with antenna on the printed circuit board or external antenna.
Sample picture:
Buy your hardware from a trusted source, at best from a dealer/online shop in your country where you have support and the right to return non-functional hardware.
When you want to buy from Amazon, AliExpress, eBay etc., take note that there is a lot of low-quality or fake hardware offered. Read customer comments and ratings carefully!
A heavily incomplete list of trusted hardware shops in germany is:
* [AZ-Delivery](https://www.az-delivery.de/)
* [Makershop](https://www.makershop.de/)
* [Berrybase](https://www.berrybase.de/)
This list is for your convenience only, the project is not related to any of these shops.
This can be achieved by copying one of the [env:....] sections from 'platformio.ini' to 'platformio_override.ini' and editing the 'platformio_override.ini' file and add/change one or more of the following lines to the 'build_flags' parameter:
* Install git and enable git in vscode - [git download](https://git-scm.com/downloads/) - [Instructions](https://www.jcchouinard.com/install-git-in-vscode/)
* Clone this repository (you really have to clone it, don't just download the ZIP file. During the build process the git hash gets embedded into the firmware. If you download the ZIP file a build error will occur): Inside vscode open the command palette by pressing `CTRL` + `SHIFT` + `P`. Enter `git clone`, add the repository-URL `https://github.com/tbnobody/OpenDTU`. Next you have to choose (or create) a target directory.
* In vscode, choose File --> Open Folder and select the previously downloaded source code. (You have to select the folder which contains the "platformio.ini" and "platformio_override.ini" file)
* Adjust the COM port in the file "platformio_override.ini" for your USB-to-serial-converter. It occurs twice:
* Select the arrow button in the blue bottom status bar (PlatformIO: Upload) to compile and upload the firmware. During the compilation, all required libraries are downloaded automatically.
* Under Linux, if the upload fails with error messages "Could not open /dev/ttyUSB0, the port doesn't exist", you can check via ```ls -la /dev/tty*``` to which group your port belongs to, and then add your user this group via ```sudo adduser <yourusername> dialout```
* Clone this repository (you really have to clone it, don't just download the ZIP file. During the build process the git hash gets embedded into the firmware. If you download the ZIP file a build error will occur)
The pre-compiled files can be found on the [github page](https://github.com/tbnobody/OpenDTU) in the tab "Actions" and the sub menu "OpenDTU Build". Just choose the latest build from the master branch (search for "master" in the blue font text but click on the white header text!). You need to be logged in with your github account to download the files.
- Press "Erase" button on screen. Look into the terminal window, you should see dots appear. Then press the "Boot" button on the ESP32 board. Wait for "FINISH" to see if flashing/erasing is done.
- To program, press "Start" on screen, then the "Boot" button.
- When flashing is complete (FINISH appears) then press the Reset button on the ESP32 board (or powercycle ) to start the OpenDTU application.
* Navigate to Settings --> Network Settings and enter your WiFi credentials. The username to access the config menu is "admin" and the password the same as for accessing the Access Point (default: "openDTU42").
* OpenDTU then simultaneously connects to your WiFi AP with these credentials. Navigate to Info --> Network and look into section "Network Interface (Station)" for the IP address received via DHCP.
* If your WiFi AP uses an allow-list for MAC-addresses, please be aware that the ESP32 has two different MAC addresses for its AP and client modes, they are also listed at Info --> Network.
* OpenDTU needs access to a working NTP server to get the current date & time. Both are sent to the inverter with each request. Default NTP server is pool.ntp.org. If your network has different requirements please change accordingly (Settings --> NTP Settings).
* Add your inverter in the inverter settings (Settings --> Inverter Settings)
* First: When there is no light on the solar panels, the inverter completely turns off and does not answer to OpenDTU! So if you assembled your OpenDTU in the evening, wait until tomorrow.
* When there is no data received from the inverter(s) - try to reduce the distance between the openDTU and the inverter (e.g. move it to the window towards the roof)
* Under Settings -> DTU Settings you can increase the transmit power "PA level". Default is "minimum".
* The NRF24L01+ needs relatively much current. With bad power supply (and especially bad cables!) a 10 µF capacitor soldered directly to the NRF24L01+ board connector brings more stability (pin 1+2 are the power supply). Note the polarity of the capacitor…
* You can try to use an USB power supply with 1 A or more instead of connecting the ESP32 to the computer.
* Double check that you have a radio module NRF24L01+ with a plus sign at the end. NRF24L01 module without the plus are not compatible with this project.
* There is no possibility of auto-discovering the inverters. Double check you have entered the serial numbers of the inverters correctly.
* OpenDTU needs access to a working NTP server to get the current date & time.
* If your problem persists, check the [Issues on Github](https://github.com/tbnobody/OpenDTU/issues). Please inspect not only the open issues, also the closed issues contain useful information.
* Another source of information are the [Discussions](https://github.com/tbnobody/OpenDTU/discussions/)
* When flashing with VSCode Plattform.IO fails and also with ESPRESSIF tool a demo bin file cannot be flashed to the ESP32 with error message "A fatal error occurred: MD5 of file does not match data in flash!" than un-wire/unconnect ESP32 from the NRF24L01+ board. Try to flash again and rewire afterwards.
