Case for ESP Resol VBus Adapter

I needed a VBus adapter for my Resol solar control system so that I could display it in HomeAssistant. The VBus adapters from Resol were all too expensive, so I decided to build one myself using an ESP8266. 

To start with, I opted for the simple version with an optocoupler. 

Required components: 

• 70x30mm circuit board (https://www.amazon.de/dp/B0D8VMQ46H)
• ESP8266, I have used an USB-C version (https://www.amazon.de/dp/B0D66LXTTK) 
• Optocoupler 817A (https://www.reichelt.de/de/de/shop/produkt/1-fach_optokoppler_5kv_35v_50ma_80-160_dip-4-269967) 
• Resistors: 3.3kOhm, 4.7kOhm 
• Wire, solder, soldering iron 
• Optional: Socket for optocoupler

The links are only examples and do not contain any affiliate data. 

Assembly

Solder the female headers into the base board and the male headers into the ESP8266. Make sure that the long side of the male headers is facing downwards so that the male headers fit into the female headers. See the pictures.

Put the base board first in the case, and then fit the ESP on it, the USB-C plug should hold the whole circuit boards it in place.

More details, such as the circuit diagram, can be found here: https://esphome.io/components/vbus/

Printing instructions: 

• Print on a flat surface, no support is required. 
• All parts in this model I printed the washer for the cable gland in TPU
• A cable gland is also required: https://www.printables.com/model/114283-cable-gland-all-sizes ‘D7_L10’ fits my cable and hole diameter
• Supports are required for the cable gland, see printing instructions there.

ESPHome code for the ESP8266 

You can also find the code for the ESP8266 here.