Help for finding a suitable sensor..

Hi Everyone,

I want to build a robot like a i-Robot Roomba which can back to its dock when running out of battery. But i don't know what sensor to use for the robot to locate its dock place. i'd read one article, they use infra red beam, but the robot cannot detect the beam if the beam avoid by an obstacle.

can anyone suggest me good sensor for that?

They're supposed to wander around until they find it. Even then they still get stuck sometimes. If you really want to go overboard and try to improve the design try integrating an optical mouse as a tracking device, then using bump mapping and a wandering scheme you could gradually build a rough map of the room so that it at least had a clue where it was it relation to the room.

Ok thanks a lot ...

i want try to make the robot can detect the signal transmited by the dock and knowledge the signal come from what angle.. but it seem too hard to make it..

You can't rely on a perfect sensor signal, you have to learn how to make the behaviors possible from the robot make the sensor technology practical. As I said previously, direct IR does not work in a varied environment, unless the robot knows how to wander about to find the signal in the first place.

ok2.. thanks , i try to figure out the other way..

What is 'the other way' ?

i mean other way from what i try to do,
i try to use your suggested method..

Good luck, post problems back here, you'll run out of time fast, but just make sure you're working and encountering problems. This is not the kind of test you can ace.

Easiest way would be mount the IR sensor on the charger to a servo and have it pan the room, Now have the robot with several IR receivers mounted on your robot so it can scan the IR and program it if it can't find the IR within a set period to go find it then continue operation. Monitor the battery voltage and when a preset voltage is reached your robot should see the IR and be able to get back to it. By putting a few extra smarts on your robot when the IR isn't seen to mark the last it was seen so when needed it can back track to that point.

Basically it all comes down to what you can do to make all this happen but I hope you get the picture.

Regards Bryan