Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: Weird Fishes on April 03, 2009, 10:34:35 AM

Title: Best sensor for detecting small and close objects
Post by: Weird Fishes on April 03, 2009, 10:34:35 AM

I am trying to figure out which type of sensor (and which model too, I suppose) would work the bet for detecting small objects (Lego bricks) on a white colour board by an autonomous robotic arm that will be approximately 5-10 cm from the ground(tip of sensor to board). What I don't know is whether a given sensor will be able to detect the brick, and be fairly accurate about it's position.

Any help would be greatly appreciated.

Title: Re: Best sensor for detecting small and close objects
Post by: Hawaii00000 on April 05, 2009, 08:06:03 PM

You might want to look into roborealm ( http://www.roborealm.com/ (http://www.roborealm.com/) ). It uses a webcam and a laptop to process images. The other option is using a ir range finder like this...

[youtube]vbhMuPF0Qj4[/youtube]

Title: Re: Best sensor for detecting small and close objects
Post by: SmAsH on April 06, 2009, 01:24:49 AM

does this sensor need to detect the color or the distance of the brick? have you considered sonar?

Title: Re: Best sensor for detecting small and close objects
Post by: superchiku on April 06, 2009, 03:37:22 AM

hey if its coloured devce ..i can help u with image processing..i have devised a method for blob detection in opencv ...it really works gr8..and yes its faster then roborealm..

Title: Re: Best sensor for detecting small and close objects
Post by: Weird Fishes on April 06, 2009, 03:12:39 PM

It doesn't need to detect colour. I've built a colour sensor already, and if I decide to include it it won't be on the end of the arm. I just ordered a sonar sensor from Pololu that claims it can detect small objects up to and touching it's face. I also have an IR sensor, so maybe I'll pair them. The IR sensor wasn't working very well before, but I think the voltage was out of range.

As for the camera, I don't think that's the best fit for this project(at least for now). I'm using an atmega168 and have little camera experience. Maybe version 3(this would be version 2 :P).

Thanks

Title: Re: Best sensor for detecting small and close objects
Post by: GearMotion on April 06, 2009, 03:22:06 PM

Perhaps think in stages. If you have a sonar sensor that gives you rough location, perhaps you can then supplement with a beam-break (IR or visible) sensor right on the robot arm.