Anyone using sensors???

[rust710]

Originally posted by Duke 13370
Remember ours didn't work earlier, this fixes it, and 127+256=393 (i forgot that 254 thing) this inverses it correctly, the one we had was backwards (close to 127 was sharper turn than 254).

127 + 254 = 127

and it is only 254.

[Josh Hambright]

Originally posted by Andrew
Is anyone else out there using encoders? I heard one person talk about odometry.
We got some gray scale mechanical encoders (Grayhill) and are using them on our back wheels.

We do the back up then forward at an angle strategy.

yes encoders.... lets just say that there is a section of our code dedicated to conversion of grey code...and that there are some funny looking things attached to our front wheels

[Elgin Clock]

Originally posted by srawls
First of all, we are not travelling in a straight line, we must travel forward, turn 90 degrees right, go forward, then travel 90 degrees right again.

Second, the distance may or may not be greater, that's not the point. When you don't do an arc, you have to stop, turn, then move, and then you have to accelerate back up to your top speed. When you do an arc, you apply power to the motors continously, and thus you aren't jerky and you save some speed.

Now, it may be different depending on drive train issues, and robots, but it's not as simple as "the shortest distance between two points is a straight line" (unless you are 179 and you can just climb over the rail, thus going in a straight line! )

Stephen

I don;t know that much about the banner sensors that we use since I'm not that electrically inclined so to speak, but I hope they are different than the sensors that the LEGO Leaugers use.. While I was volunteering these past 2 years at LEGO League events, I noticed how jumpy those sensors that they use to "line track" are. Do ours have the same jumpiness to them??? I hope not.

[srawls]

I worked a lot with the sensors over this summer for a NASA internship, and while they were somewhat "jumpy" when they were on the verge of sensing something, they tended to be very reliable. Also, I think the jumpiness that I expririenced was probably germain to my project (tracking a contiously moving object through 3-dimensional space), and that the sensors would be very well suited for line tracking. I haven't actally made a line tracker though, so I can't tell you for sure.

Stephen

[Willum]

We were able to hook up some sensors to last years robot and found that there was little to no jumpiness in them.

However the bot was somewhat slow at 3-5 fps, and getting that to work right was hard. I can imagine any team that is looking for 10+ fps to line track is going insane getting that to work.

The problem i found with the sensors is that they really don't pick up the reflective tape at a distance large enough to be worth using. aka tote seeking. though the cool factor is through the roof on something like that it's difficult to imagine it being reliable. The sensors are fairly reliable at a short distance like that used for line tracking. So it is possible that some teams may have perfected such a code.

[steveg]

Originally posted by Elgin Clock
I don;t know that much about the banner sensors that we use since I'm not that electrically inclined so to speak, but I hope they are different than the sensors that the LEGO Leaugers use.. While I was volunteering these past 2 years at LEGO League events, I noticed how jumpy those sensors that they use to "line track" are. Do ours have the same jumpiness to them??? I hope not.

Elgin:

The Banners are _much_ better than the LEGO light sensors (I hope, anyway). In any event, the location of them on our arm should be able to allow us to use the same two sensors for both line tracking and stack destruction during autonomous mode. Of course, the line follow code is not made yet, but that's another story all together.

[Melissa Nute]

I know we attempted to use the sensors; however, some of the were broken in the process *cough*bypeoplerunningtheprototypeintomycar*cough* or when they were working, our speed was too fast in order to stay focused on the line.

Dead Recking was the way to go for us at least.

[Raven_Writer]

Originally posted by Meli W.
*cough*bypeoplerunningtheprototypeintomycar*cough*

I did this to a guy's classic car when I was driving a 4 wheeler once, got in a bit of trouble to (-.-);

Sensors come in handy sometimes.

[Elgin Clock]

Originally posted by steveg
Elgin:

The Banners are _much_ better than the LEGO light sensors (I hope, anyway). In any event, the location of them on our arm should be able to allow us to use the same two sensors for both line tracking and stack destruction during autonomous mode. Of course, the line follow code is not made yet, but that's another story all together.

I have faith in you electrical people, Steve! lol

For everyone else, "See" my post in THIS thread to "see" how we wowwed everyone last year with the sensors with our "I.D.A.N. System"

[mav]

we found the sensors to be too unreliable so we are using a distance measuring and a gyro in autonomus mode. about tote seeking we found to hard to program due to the lack of a constant background (example: the crowd not reliable)

[Josh Hambright]

i dont think that 'background' will be an issue...
unless someone out in the crowd is standing at the exact hight of the tape on the boxes and has something retroreflective.

The range of these sensors when trying to sense something not retro reflective is very limited. They cant even sense a hand 1' away.

[Yan Wang]

Odd... the talk of sensors here is only related to the use of them for travelling up the ramp...

However, what if your alliance partner is faster than you by a significant amount? Couldn't you contribute more by using sensors to find a human player stack (so you can steal it immediately when the human control starts) or go and knock them down.

Anyway, that's just another use for sensors if you don't want four robots running into each other

[Josh Hambright]

i totaly agree...

when i say we have sensors we have a whole range of stuff. From rotary encoders to limit switches to banner sensors to pots to the yaw rate sensor. We did research into some others like other ways of sensing a change in angle and different types of sensors to sense position on the field but we ran out of digital inputs cuz we are using 4 bit rotary encoders (these were fun to wire and figure out the non documented pinout!).

Sensors rock, our team went crazy with them this year!