How do I build this?

[BurntBiscuits]

Hello everyone, this is my first post to this board after finding it through Google. I'm generally inexperienced with electronics so I was wondering if you could help me figure out how to build something.

Now, I'm generally quite a forgetful person and as a result of this I've lost countless memory sticks. So, I've been thinking about building something to remind me if I'm leaving one behind.

My idea is to create some sort of system that consists of two devices. One attached to my memory stick and another I'll keep in my pocket, or attached to my phone (Which I rarely lose). The idea is that when I put too much distance between the two devices, the device in my pocket will beep or vibrate to remind me.

Problem is, I have no idea where to start or if this is even possible. I'd obviously prefer to keep these devices as small as possible and in some sort of protective case. I also don't really want to be spending too much, I'd say no more than £10? That's just a wild guess though, I have no idea what I'll need after all.

So, does anyone have any ideas of how I could construct this while keeping it relatively small and cheap? I'd appreciate any advice you could give me

Thanks in advance

[zapper]

Hi Burntbiscuits,
Like yourself this is my first post.

As you'll no doubt want whatever is attached to your 'phone to be small and unobtrusive I believe self building something like this is going to be impractical; given your inexperience you'll probably end up with two modules each the size of a matchbox, a typical example of over-complicating a simple solution.
So please don't regard what I suggest as discouragement from using electronics to solve problems in future .......
why not simply attach you memory stick to the phone using the lanyard usually provided with each?