Hey LMR. I'm going to be brutally honest and forward about my plans for a robot...
I want it to chase people.
Are there any kinds of sensor devices that would somehow detect a person to run towards it? I'm thinking something that detects motion would be ideal.
This is…
This is your first project, is it?
Yes…Am I trying to run
Yes…
Am I trying to run before I’ve learned to walk with this one?
Oh yeah.
There will be a lot of steps to be learned to get to your eventual goal. I can also say that there is a huge difference between following and chasing. Most folks work a long time just to get to the “following” stage. To answer your question, there is not really a “there is a person over there at x heading” sensor, there are tricky ways to use “regular” sensors to make a pretty good guess that the robot is looking at a person.
On the other hand, if you can accept that your first robot is probably not going to be chasing anyone, this is a pretty cool hobby. The fact of the matter is that you can build a robot, and from there, its functionality is limited only by what is in your brain. Code and logic give you fun puzzels to solve --much fun.
All of us started the same way, get a microcontroller of some kind, picaxe, arduino, prop, etc and make a LED blink. Or grab a Start Here robot --A helluva deal at 100 bucks or so and there is a ton of info and people around here to give you a hand.
Perhaps I should get my head
Perhaps I should get my head out of the clouds and start with the SHR to understand my limitations first. Thanks for your help :).
Start with the SHR and then
Start with the SHR and then you can add functionality to it as you learn. a PIR sensor will allow you to detect mammals (and candles…) with some accuracy. But CTC is right, you are going to have a hard time doing this without some intermediate steps.
No need to get your head out of the clouds
Just make sure your feet are grounded, so you can make intelligent decisions about how to get to where your head is. 
