Hi there, i am starting a new project here, where i want to make a wireless petrol pump.
You mean a pump at a service station (gas station?) I'm not sure exactly what kind of petrol pump you have.
so i have done the hardware part till the pump works by using arduino mega. now, i want to add features so that i can change the petrol price (changing the coding) wirelessly without me having to reconnect my arduino to pc and reupload the programming.
OK, this is a reasonable request.
The clue is "without re-uploading". You want to save a price variable on the Arduino which doesn't change when the power goes out or for any other reason until you request it.
Use the EEPROM memory. It's very easy to save a value in the EEPROM and it stays 'forever'.
is there any way for me to do it? maybe by using wifi shield or something?
So you don't currently have communications with the Arduino outside of the programming cable? Woluld a wired solution also work for you?