Open door and send signal to PC or mobile phone / Abrir porta e mandar sinal para o pc ou telemovel

[Dave_Lowther]

@arondacunha

it will be more or less 1km from the computer/cell phone

I have no experience with 1km wireless transmission.
Perhaps this other topic will contain some helpful ideas. I haven't read it fully. I just googled for "arduino 1km radio signal" and found it in the search results.