Wiring two cameras

The newest team update stated that we could use two cameras, our team is considering a use for both of the cameras. None of our Electronics team or other members can figure out how to wire the two cameras though. So how would you wire two cameras up to the TTL Serial Port on the RC?

You’ll probably want to hook one camera to the TTL port and the other to the programming port. It will be very difficult to multiplex the TTL port for two cameras, requiring both electronics to switch between the cameras AND a good deal of software development to deal with both. You can’t talk to two cameras at the same time over one serial port.

Are you sure they said you can? I mean, I remember a team update that said you can’t…

Nevermind… thats odd…

It was changed in Team Update #3.


Rule # 1007, ‘You may use a 2nd vision camera with your robot.’

I think that this rule being in place, there should be a semi-simplistic solution to have two cameras. I appreciate your help Dave, but I still think there might be another way to wire them both.

We get TWO?!

No, you get one in the Kit of Parts, but FIRST is allowing you to use two on the robot. You would have to order another one from Innovation First at http://www.ifirobotics.com

I know… read the whole post… :rolleyes:

To the first team that successfully enables two CMUcamIIs on their robot and uses the PIC microprocessor in the IFI robot controller to compute the stereo correlation from the two camera images to determine range to the designated target, within the time limits of the autonomous period, I will personally award six dozen Krispy Kreme donuts.

Yes, it is physically and electrically possible to connect multiple CMUcams to the RC. But once you do, what are you going to do with the data?


(OK, now that I have said this, just watch someone like Kevin Watson have a working solution by this Friday… :yikes: )

Me any my friend used two old CMU cameras (the current release in the summer of 2003) to do that, although the Acroname GP boards weren’t powerful enough to do it very well. In short we had our trikebot find a target, aim, and fire a paintball gun at it (all done on a 2d plane though, 3d wasn’t possible, processor too slow). The theory sounded cool, never did get it to perfectly work though… But hey, with the new CMUII cams and PIC processors, shouldn’t be too hard :smiley: :smiley: :D.


I just happen to be working on getting the camera code to work with my serial port driver. And now that you mention it, it wouldn’t be too hard to have a second instance of the camera code running… Does your offer include those really tasty glazed, raspberry filled gems?


I knew almost as fast as I typed that message that it would be a mistake. :slight_smile: Yes, if you get a stereo correlation algorithm working on the PIC with two CMUcamIIs that runs fast enough to provide a solution within the 15 seconds of the autonomous period, then the award will include 72 delectable morsels of your choice. And I already know where all the Krispy Kreme stores in LA are located (actually, the Burbank store may be closer).

OK, so is anyone else going to give Kevin a challenge for the donuts?


program our robot and you will recieve two dozen doughnuts…that’d be cool just to say NASA programmed our robot :wink:

I’ll tell you what, Dave. Mail me another CMU cam, and I’ll gladly demonstrate two-camera code for you in Atlanta. :stuck_out_tongue:

Conceptually, it’s not that difficult. Get them both operational (with a little help from Kevin), and mount them on opposite corners of the front your robot. You know the width of your robot (likely 28"), and you can get the two angles from the values of the pan servos. You have angle-side-angle, and there’s only one solution to the triangle. Now you know how far away you are. Pivot until the two base angles are congruent, and charge forward until you’re the proper distance from the vision tetra. Use the same theory with the yellow triangle to the goal. It’s very doable, and I’d love to pull it off. I can’t think of a more incredible nerd feat attainable at this age than to meet Dave Lavery’s personal challenge. :wink:

That being said, I don’t think my team is interested in spending $200 on 72 donuts. Thanks for the offer, though, Dave. :rolleyes:

You know he was just waiting for someone to raise the stakes high enough! 72 is too rich for my blood, I fold.

Actually, conceptually it is not that simple. Remember, the challenge is to come up with a real stereo correlation solution, not a simple geometric one. The biggest problem is that there are multiple vision tetras out on the field. You have to compute the true correlation between the camera images to determine if both cameras are looking at the same target. Only then can you back-solve the geometry.

If I am going to give away six dozens tasty treats without allowing any for myself, I have to make sure that the challenge is really worth it! C’mon, are you all going to leave Kevin as the only contender?


I like Donuts :smiley:

if i cant get some more funds maybe i can convince our programmer to do it
…He likes donuts too :cool:

I think it’s doable, with enough if statements. :stuck_out_tongue: But, once again, my inspiration is not limited by lack of programming prowess, or lack of time, but rather lack of resources. Pity we don’t have a mob boss coughbeattycough doing our fundraising, or I’d be all over this. :wink: Enjoy the donuts, Kevin.


Well, I’ve hit a snag. After an all-night Mountain Dew and pizza-fueled programming session, I’ve got 19 robot controllers setup as a pipelined stereo vision processor running the 27,000 lines of MER stereo vision code that I ported to PIC C18. I have an additional 53 robot controllers running a pipelined version of the MER “GESTALT” local path planner. Everything seems to run pretty well, but my EX18-12 battery completely discharges in only 5 seconds. I asked the crack FIRST engineering staff to make an exception to rule <R46> and allow me to add the additional three batteries I need, but they wouldn’t budge. I then asked if I could use a flux capacitor for power, but that didn’t go over too well, either (they did say I could use it for decorative purposes, though). Anyway, can I get some partial credit for the effort? I’d be pretty happy with just two dozen.


If you use the flux capacitor your robot will still have to drive 88mph. :ahh: