Hey all..I have an idea of implementing sensors such as radiation,temp and humidity,levels of carbon dioxide and carbon monoxide and combustible gases on arduino yun.i wanted to access all the information through an app in the mobile.I have no idea where to start the project and it would be good if anyone can help me by suggesting anything
First you need to identify one sensor and write a short program to get data from it and display it on the Arduino Serial Monitor.
Same thing (separately) for each of the other sensors.
Then you need to learn how to create a program that can send a short message to your mobile.
When you can do all those things separately it will be time to join them together.
Have you considered setting your Yun up as a web server and connecting to it with Wifi from your phone. Then you need no app in your phone - just the browser.