Further to my Bluetooth version and great feedback from this site, I have now released an updated design of the DCC system using the ESP32 node MCU module instead of Bluetooth. This allows the user to have more than one mobile phone throttle for club layouts etc.
For build details, please refer to 'Instructables' website.
[Website, PCB and app links removed by moderator because they violate forum policy on buying & selling and advertising.]