Re: What sensors are used to detect the hot LED lights on the FRC field?
 

Thanks Alan,

I guess I can buy that would work in Theory... but my question is more along the lines of how do you know you are pointing ONLY at the horizontal target when placing on the field?

What does the person placing the robot on the field see/use to confirm the light is on the horizontal target, if the light is reflected back is to the sensor.

In the case of Laser, maybe the person can try and place their eye near the sensor everytime to confirm location, but how do you do this with an IR which is not in the visible spectrum?

It seems like this is a cumbersum way to position the robot, especially if you have to position the bot and continuously place your eye near the sensor for confirmation. Am I overlooking something? Somehow you need to guarantee you are not looking at the vertical target so you don't get false responses.

Does this system require, another method for position the robot to increase likelyhood that you are looking at the right point?

Regards,
Kevin

Re: What sensors are used to detect the hot LED lights on the FRC field?
 

You hit the nail on the head Alan! :)

The sensor I posted actually has a built in sensing light that illuminates when "the circuit is complete" for lack of a better term. This is all internal to the sensor. If the target is present both a green and amber light located on the top of the sensor will illuminate, if there is power to the sensor, but the target is not present, only the green light illuminates. That's the elegance behind a sensor of this design. Very easy to recognize the presence of the target without any additional coding or alignment mechanism. We weren't sure if this was the route we could take pre-Team Update 1... but after we learned that pre match setup will have both targets revealed, we went for it!

Like I said before, camera stuff consumes a lot of resources (at least on our team) e.g. coding time, debug time, and bandwidth among others, and we only use vision if we rule out all other possibilities. 5 extra points didn't seem worth consuming those resources to us, but in 1625 nature... we still wanted those points! haha So we opted for the laser. Team 2451 (formerly 2949) did a similar laser setup in 2012, from which we drew inspiration.


EDIT: In regards to I guess it is a mixture of what I said above as well as both the retro-reflective properties of the tape and "trial and error" really... The retro reflectability of the tape will help us ensure there is no "spillage" of light from the vertical segment of tape, and "trial and error" helps improve our drive teams ability to position the sensor accurately. This "trial and error" methodology seems cumbersome yes, but most dead reckoned auton systems have some degree of this process.

Re: What sensors are used to detect the hot LED lights on the FRC field?
 

I agree with the "not use vision if you don't have too." In 2012, we were a team that had no vision on our robot. Our drivers used a line marker at the tail of robot to line up with the center of the key to make key shots. IT was actually a point of pride after a while to have the performance we did without vision. We ranked 1st seed in both regionals we attended that year, so it worked out well for us.

This year, we have vision running on a beaglebone using opencv and ffmpeg. It was a system we received from our friends 118, and have been modifying for our specific use.

I was curious about placement of the robot, because your initial post metioned it was an IR sensor. I didn't see wavelength specified on the link you provided, but I do honestly hope this system works out for you.

It will be pretty cool to see such a simple system reliably work in auton. My fear would be the initial lineup, and shooting prematurely because I was looking at the horizontal target instead of the vertical, but it sounds like you have a plan to overcome that.

Goodluck.

Reagrds,
Kevin

Re: What sensors are used to detect the hot LED lights on the FRC field?
 

Sounds like a pretty neat setup! I hope it works out for you! I am anxious to see how well our system performs. It's hard to tell at the moment because I am at college 300mi away from my former team ( The one I now mentor (sorta) lol )! We shall see! :)

I'll provide followup and/or perpetuate this conversation when I know more! Good Luck!!

Re: What sensors are used to detect the hot LED lights on the FRC field?
 

What else could be done to detect the hot high goals, because my team doesn't have a Kinect device

Re: What sensors are used to detect the hot LED lights on the FRC field?
 

I set up an Axis camera at the front of the bot and sent the video feed into Roborealm to target where in my field of view are various saturated points. Then, since the range is fairly open to prevent not catching the LEDs (just a precaution), I blob them into objects, take out all but the biggest one and put a crosshair value in the centre of the object. This way, despite lights above the field, white banners lying around, etc we can find out where the largest object on the field is. The angle of our camera also allows us to see both sides of the field--even if they aren't 100% in view, the object is filled large enough to outdo any other possible source of light.

The X and Y values of the crosshair are then sent through network tables to the cRIO, and a final, global variable in the command-based code I use shows me where it starts out hot first: left or right. If it's hot on the side I'm on, I shoot and move forward while retracting our arm (maybe a video will come soon!). If it isn't, then a timer I made waits 5.5 seconds until it will inevitably pop into hot and fire. If it's the centre I'm shooting at, then I use that global variable (isRight) to go forward, spin a bit with a PID loop and fire.

The 2-ball auto does some other hoomawazits, and our three-ball will only focus on whether the goal is hot or not after every other possible thing is done. It would be nifty to have a 3-ball hot auto, but one can only dream.

I think I went out of vision processing and into the full autonomous. Oh well, it's late and six weeks of programming really changes how you function ;)

Re: What sensors are used to detect the hot LED lights on the FRC field?
 

I hate to say this, but I received an email regarding the photoelectric sensor I posted, and upon further review of the links, I noticed I gave the incorrect sensor! The sensor I linked was the one we originally attempted to use with no luck. The correct sensor can be found here. I am sorry for the confusion I may have caused anyone trying to use a similar setup. I wish you all luck!

Re: What sensors are used to detect the hot LED lights on the FRC field?
 

What is your experience with using the Kinect at the regional you attended? How did you set it up at the driver station and who was the person (driver, operator, drive coach?) the Kinect was sensing. Was there any problem with 3 people standing close together behind the driver station?