Hey,
I go through your requirements of developing portable advertising screen for taxi. I can develop the device with electronic and codes for functioning which have all features you mentioned and controlled by the app.
We are a team with experience in electronic and IOT.
We have worked on numbers of project on IOT, and electronics. You can go through my previous design by this link [login to view URL]
Please respond on chat, we can further discuss on project and start working on it immediately.
Looking forword to assist you with my services.
Regards
Shivam Jha