I need a CAN adapter for a special job and decided to build my own. I use ESP32 to get Wifi, Bluetooth and USB Connectivity, but I decided on adding a STM32 to get dual CAN Connectivity. ESP32 do have an undocumented CAN port as well, but I assume ExpressIF have their reasons for hiding it. The display is because I also want to use this as an Analyzer sniffing. And as a adapter of this type will be connecting to industrial equipment I also want the galvanic issolation.
This will cost me around 20.- USD in components + display and boxing, but to buy something like this I would probably have to pay 500.- to 1000.- USD if I could find one.
I have listed both UART and SPI for communication between ESP32 and STM32 because I am unsure about both on ESP32. I know they exist, but have no experience with them so I can as well just Connect both . I also added a battery option on the PSU.