Tracking an indoor model plane

I have a little grasshopper flying model that I'd like to control with my arduino to fly a circuit thru my house.

I think I can figure out how to fake out the controller to give it inputs and I would start with simple timing like: "motor on, wait 3.5 sec, hard left, wait 1 sec" could get me across the living room and into the hall.

I need some way to track the model or at least synch its location once it's in the air. Ideally I would have one or more sensors that would see the model as it passed but the only thing I can really think of is a thread that attached to the back that would pull an insulator out from between some contacts so I could tell it was predictably on its way.

Any ideas? This thing is quite small by the way and mostly made of foam. It does make a pretty good flapping noise so maybe a microphone in a tube?

Couple of webcams and a couple weeks of playing with Processing?

How about having it blast some IR out the top or sides and just have sensors detect the IR?

So you have a few LEDs on the top and the sensors on the ceiling?

The plane might not be able to accept that type of additional cargo.

In that case you could use an independent beam - where you have emitter on the floor, detectors on the ceiling - and when the plane flies through the beams you know where it is!

This would be more cost effective than webcams if that is a factor

Thanks a lot.

So far the webcam/processing idea sounds quite doable. It just hadn't crossed my mind - i was stuck in arduino mode. There are amazing examples of motion detection and backround subtraction to build on. One of them divides the image into a grid and can report which cells see movement so I can get a height reference too. seems perfect at least for the first synchronization hack. I'll try to get it across the living room and out the hallway door then do dead reckoning from there. I may need another webcam in the family room but I'll cross that bridge when I come to it.

It think using some sort of IR or Sound activated 'speed trap' style device would be good.

Maybe having a track of IR emitters and detectors. The only addition to the plane would be some photo-reflective material.

Like line-following, but with a distance!

An idea...

I think I can figure out how to fake out the controller to give it inputs


umm... yeah, about that part. Looking inside the controller I was a bit surprised to see that the variable controls are not the potentiometers I was expecting. Instead they seem to be some sort of digital encoders. The throttle for example looks a bit like a pot. with a 1/2 turn movement but instead of 2 or 3 wires it has 5 and it looks like moving the lever makes or breaks various combinations between them. The 5 wires go directly to individual leads on an unmarked IC.

I've googled and googled without seeing anything like this described - does it ring a bell with anyone?

how about mounting some servo's to move the levers

looks like moving the lever makes or breaks various combinations between them

That sort of thing is called a shaft encoder. Use a meter or scope to look at the digital signals it produces. It should be a lot easer to interface to than pots.