Before you send a proposal, read this description. And make sure that you understand, and that you have the skills to make this happen. Do NOT send me a copy paste proposal please. Write a proposal that refers to this task:
I need to develop an app that works as an timer to activate lock screen.
Meaning that you will open the app, set a timer (as an example 30 minutes) and you exit the app.
When the time has run out, it locks the screen. (like if you would click the "off button" on the iPad)
Let me know if you have the skills to do this, how much time you will need (you will be given exact design files for the design) and the cost to get this done.